test_elementtree.py

# -*- coding: utf-8 -*-

"""
Tests for the ElementTree API

Only test cases that apply equally well to etree and ElementTree
belong here. Note that there is a second test module called test_io.py
for IO related test cases.
"""

from __future__ import absolute_import

import copy
import io
import operator
import os
import pyexpat
import re
import sys
import textwrap
import unittest
from contextlib import contextmanager
from functools import wraps, partial
from itertools import islice

from .common_imports import (
    BytesIO, etree, HelperTestCase,
    ElementTree, cElementTree, ET_VERSION, CET_VERSION, IS_PYPY,
    filter_by_version, fileInTestDir, canonicalize, tmpfile,
    _str, _bytes, unicode, IS_PYTHON2
)

if cElementTree is not None and (CET_VERSION <= (1,0,7) or sys.version_info[0] >= 3):
    cElementTree = None

if ElementTree is not None:
    print("Comparing with ElementTree %s" % getattr(ElementTree, "VERSION", "?"))

if cElementTree is not None:
    print("Comparing with cElementTree %s" % getattr(cElementTree, "VERSION", "?"))


def et_needs_pyversion(*version):
    def wrap(method):
        @wraps(method)
        def testfunc(self, *args):
            if self.etree is not etree and sys.version_info < version:
                raise unittest.SkipTest("requires ET in Python %s" % '.'.join(map(str, version)))
            return method(self, *args)
        return testfunc
    return wrap


def et_exclude_pyversion(*version):
    def wrap(method):
        @wraps(method)
        def testfunc(self, *args):
            if self.etree is not etree and sys.version_info[:len(version)] == version:
                raise unittest.SkipTest("requires ET in Python %s" % '.'.join(map(str, version)))
            return method(self, *args)
        return testfunc
    return wrap


class _ETreeTestCaseBase(HelperTestCase):
    etree = None
    required_versions_ET = {}
    required_versions_cET = {}

    def XMLParser(self, **kwargs):
        try:
            XMLParser = self.etree.XMLParser
        except AttributeError:
            assert 'ElementTree' in self.etree.__name__
            XMLParser = self.etree.TreeBuilder
        return XMLParser(**kwargs)

    try:
        HelperTestCase.assertRegex
    except AttributeError:
        def assertRegex(self, *args, **kwargs):
            return self.assertRegexpMatches(*args, **kwargs)

    @et_needs_pyversion(3, 6)
    def test_interface(self):
        # Test element tree interface.

        def check_string(string):
            len(string)
            for char in string:
                self.assertEqual(len(char), 1,
                        msg="expected one-character string, got %r" % char)
            new_string = string + ""
            new_string = string + " "
            string[:0]

        def check_mapping(mapping):
            len(mapping)
            keys = mapping.keys()
            items = mapping.items()
            for key in keys:
                item = mapping[key]
            mapping["key"] = "value"
            self.assertEqual(mapping["key"], "value",
                    msg="expected value string, got %r" % mapping["key"])

        def check_element(element):
            self.assertTrue(self.etree.iselement(element), msg="not an element")
            direlem = dir(element)
            for attr in 'tag', 'attrib', 'text', 'tail':
                self.assertTrue(hasattr(element, attr),
                        msg='no %s member' % attr)
                self.assertIn(attr, direlem,
                        msg='no %s visible by dir' % attr)

            check_string(element.tag)
            check_mapping(element.attrib)
            if element.text is not None:
                check_string(element.text)
            if element.tail is not None:
                check_string(element.tail)
            for elem in element:
                check_element(elem)

        element = self.etree.Element("tag")
        check_element(element)
        tree = self.etree.ElementTree(element)
        check_element(tree.getroot())
        element = self.etree.Element(u"t\xe4g", key="value")
        tree = self.etree.ElementTree(element)
        # lxml and ET Py2: slightly different repr()
        #self.assertRegex(repr(element), r"^<Element 't\xe4g' at 0x.*>$")
        element = self.etree.Element("tag", key="value")

        # Make sure all standard element methods exist.

        def check_method(method):
            self.assertTrue(hasattr(method, '__call__'),
                    msg="%s not callable" % method)

        check_method(element.append)
        check_method(element.extend)
        check_method(element.insert)
        check_method(element.remove)
        # Removed in Py3.9
        #check_method(element.getchildren)
        check_method(element.find)
        check_method(element.iterfind)
        check_method(element.findall)
        check_method(element.findtext)
        check_method(element.clear)
        check_method(element.get)
        check_method(element.set)
        check_method(element.keys)
        check_method(element.items)
        check_method(element.iter)
        check_method(element.itertext)
        # Removed in Py3.9
        #check_method(element.getiterator)

        # These methods return an iterable. See bug 6472.

        def check_iter(it):
            check_method(it.next if IS_PYTHON2 else it.__next__)

        check_iter(element.iterfind("tag"))
        check_iter(element.iterfind("*"))
        check_iter(tree.iterfind("tag"))
        check_iter(tree.iterfind("*"))

        # These aliases are provided:

        # not an alias in lxml
        #self.assertEqual(self.etree.XML, self.etree.fromstring)
        self.assertEqual(self.etree.PI, self.etree.ProcessingInstruction)

    def test_element(self):
        for i in range(10):
            e = self.etree.Element('foo')
            self.assertEqual(e.tag, 'foo')
            self.assertEqual(e.text, None)
            self.assertEqual(e.tail, None)

    def test_simple(self):
        Element = self.etree.Element

        root = Element('root')
        root.append(Element('one'))
        root.append(Element('two'))
        root.append(Element('three'))
        self.assertEqual(3, len(root))
        self.assertEqual('one', root[0].tag)
        self.assertEqual('two', root[1].tag)
        self.assertEqual('three', root[2].tag)
        self.assertRaises(IndexError, operator.getitem, root, 3)

    # test weird dictionary interaction leading to segfault previously
    def test_weird_dict_interaction(self):
        root = self.etree.Element('root')
        self.assertEqual(root.tag, "root")
        add = self.etree.ElementTree(file=BytesIO('<foo>Foo</foo>'))
        self.assertEqual(add.getroot().tag, "foo")
        self.assertEqual(add.getroot().text, "Foo")
        root.append(self.etree.Element('baz'))
        self.assertEqual(root.tag, "root")
        self.assertEqual(root[0].tag, "baz")

    def test_subelement(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        root = Element('root')
        SubElement(root, 'one')
        SubElement(root, 'two')
        SubElement(root, 'three')
        self.assertEqual(3, len(root))
        self.assertEqual('one', root[0].tag)
        self.assertEqual('two', root[1].tag)
        self.assertEqual('three', root[2].tag)

    def test_element_contains(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        root1 = Element('root')
        SubElement(root1, 'one')
        self.assertTrue(root1[0] in root1)

        root2 = Element('root')
        SubElement(root2, 'two')
        SubElement(root2, 'three')
        self.assertTrue(root2[0] in root2)
        self.assertTrue(root2[1] in root2)

        self.assertFalse(root1[0] in root2)
        self.assertFalse(root2[0] in root1)
        self.assertFalse(None in root2)

    def test_element_indexing_with_text(self):
        ElementTree = self.etree.ElementTree

        f = BytesIO('<doc>Test<one>One</one></doc>')
        doc = ElementTree(file=f)
        root = doc.getroot()
        self.assertEqual(1, len(root))
        self.assertEqual('one', root[0].tag)
        self.assertRaises(IndexError, operator.getitem, root, 1)

    def test_element_indexing_with_text2(self):
        ElementTree = self.etree.ElementTree

        f = BytesIO('<doc><one>One</one><two>Two</two>hm<three>Three</three></doc>')
        doc = ElementTree(file=f)
        root = doc.getroot()
        self.assertEqual(3, len(root))
        self.assertEqual('one', root[0].tag)
        self.assertEqual('two', root[1].tag)
        self.assertEqual('three', root[2].tag)

    def test_element_indexing_only_text(self):
        ElementTree = self.etree.ElementTree

        f = BytesIO('<doc>Test</doc>')
        doc = ElementTree(file=f)
        root = doc.getroot()
        self.assertEqual(0, len(root))

    def test_element_indexing_negative(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement
        a = Element('a')
        b = SubElement(a, 'b')
        c = SubElement(a, 'c')
        d = SubElement(a, 'd')
        self.assertEqual(d, a[-1])
        self.assertEqual(c, a[-2])
        self.assertEqual(b, a[-3])
        self.assertRaises(IndexError, operator.getitem, a, -4)
        a[-1] = e = Element('e')
        self.assertEqual(e, a[-1])
        del a[-1]
        self.assertEqual(2, len(a))

    def test_elementtree(self):
        ElementTree = self.etree.ElementTree

        f = BytesIO('<doc><one>One</one><two>Two</two></doc>')
        doc = ElementTree(file=f)
        root = doc.getroot()
        self.assertEqual(2, len(root))
        self.assertEqual('one', root[0].tag)
        self.assertEqual('two', root[1].tag)

    def test_text(self):
        ElementTree = self.etree.ElementTree

        f = BytesIO('<doc>This is a text</doc>')
        doc = ElementTree(file=f)
        root = doc.getroot()
        self.assertEqual('This is a text', root.text)

    def test_text_empty(self):
        ElementTree = self.etree.ElementTree

        f = BytesIO('<doc></doc>')
        doc = ElementTree(file=f)
        root = doc.getroot()
        self.assertEqual(None, root.text)

    def test_text_other(self):
        ElementTree = self.etree.ElementTree

        f = BytesIO('<doc><one>One</one></doc>')
        doc = ElementTree(file=f)
        root = doc.getroot()
        self.assertEqual(None, root.text)
        self.assertEqual('One', root[0].text)

    def test_text_escape_in(self):
        ElementTree = self.etree.ElementTree

        f = BytesIO('<doc>This is &gt; than a text</doc>')
        doc = ElementTree(file=f)
        root = doc.getroot()
        self.assertEqual('This is > than a text', root.text)

    def test_text_escape_out(self):
        Element = self.etree.Element

        a = Element("a")
        a.text = "<>&"
        self.assertXML(_bytes('<a>&lt;&gt;&amp;</a>'),
                       a)

    def test_text_escape_tostring(self):
        tostring = self.etree.tostring
        Element  = self.etree.Element

        a = Element("a")
        a.text = "<>&"
        self.assertEqual(_bytes('<a>&lt;&gt;&amp;</a>'),
                         tostring(a))

    def test_text_str_subclass(self):
        Element = self.etree.Element

        class strTest(str):
            pass

        a = Element("a")
        a.text = strTest("text")
        self.assertXML(_bytes('<a>text</a>'),
                       a)

    def test_tail(self):
        ElementTree = self.etree.ElementTree

        f = BytesIO('<doc>This is <i>mixed</i> content.</doc>')
        doc = ElementTree(file=f)
        root = doc.getroot()
        self.assertEqual(1, len(root))
        self.assertEqual('This is ', root.text)
        self.assertEqual(None, root.tail)
        self.assertEqual('mixed', root[0].text)
        self.assertEqual(' content.', root[0].tail)

    def test_tail_str_subclass(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        class strTest(str):
            pass

        a = Element("a")
        SubElement(a, "t").tail = strTest("tail")
        self.assertXML(_bytes('<a><t></t>tail</a>'),
                       a)

    def _test_del_tail(self):
        # this is discouraged for ET compat, should not be tested...
        XML = self.etree.XML

        root = XML(_bytes('<doc>This is <i>mixed</i> content.</doc>'))
        self.assertEqual(1, len(root))
        self.assertEqual('This is ', root.text)
        self.assertEqual(None, root.tail)
        self.assertEqual('mixed', root[0].text)
        self.assertEqual(' content.', root[0].tail)

        del root[0].tail

        self.assertEqual(1, len(root))
        self.assertEqual('This is ', root.text)
        self.assertEqual(None, root.tail)
        self.assertEqual('mixed', root[0].text)
        self.assertEqual(None, root[0].tail)

        root[0].tail = "TAIL"

        self.assertEqual(1, len(root))
        self.assertEqual('This is ', root.text)
        self.assertEqual(None, root.tail)
        self.assertEqual('mixed', root[0].text)
        self.assertEqual('TAIL', root[0].tail)

    def test_ElementTree(self):
        Element = self.etree.Element
        ElementTree = self.etree.ElementTree

        el = Element('hoi')
        doc = ElementTree(el)
        root = doc.getroot()
        self.assertEqual(None, root.text)
        self.assertEqual('hoi', root.tag)

    def test_attrib(self):
        ElementTree = self.etree.ElementTree

        f = BytesIO('<doc one="One" two="Two"/>')
        doc = ElementTree(file=f)
        root = doc.getroot()
        self.assertEqual('One', root.attrib['one'])
        self.assertEqual('Two', root.attrib['two'])
        self.assertRaises(KeyError, operator.getitem, root.attrib, 'three')

    def test_attrib_get(self):
        ElementTree = self.etree.ElementTree

        f = BytesIO('<doc one="One" two="Two"/>')
        doc = ElementTree(file=f)
        root = doc.getroot()
        self.assertEqual('One', root.attrib.get('one'))
        self.assertEqual('Two', root.attrib.get('two'))
        self.assertEqual(None, root.attrib.get('three'))
        self.assertEqual('foo', root.attrib.get('three', 'foo'))

    def test_attrib_dict(self):
        ElementTree = self.etree.ElementTree

        f = BytesIO('<doc one="One" two="Two"/>')
        doc = ElementTree(file=f)
        root = doc.getroot()
        attrib = dict(root.attrib)
        self.assertEqual('One', attrib['one'])
        self.assertEqual('Two', attrib['two'])
        self.assertRaises(KeyError, operator.getitem, attrib, 'three')

    def test_attrib_copy(self):
        ElementTree = self.etree.ElementTree

        f = BytesIO('<doc one="One" two="Two"/>')
        doc = ElementTree(file=f)
        root = doc.getroot()
        attrib = copy.copy(root.attrib)
        self.assertEqual('One', attrib['one'])
        self.assertEqual('Two', attrib['two'])
        self.assertRaises(KeyError, operator.getitem, attrib, 'three')

    def test_attrib_deepcopy(self):
        ElementTree = self.etree.ElementTree

        f = BytesIO('<doc one="One" two="Two"/>')
        doc = ElementTree(file=f)
        root = doc.getroot()
        attrib = copy.deepcopy(root.attrib)
        self.assertEqual('One', attrib['one'])
        self.assertEqual('Two', attrib['two'])
        self.assertRaises(KeyError, operator.getitem, attrib, 'three')

    def test_attributes_get(self):
        ElementTree = self.etree.ElementTree

        f = BytesIO('<doc one="One" two="Two"/>')
        doc = ElementTree(file=f)
        root = doc.getroot()
        self.assertEqual('One', root.get('one'))
        self.assertEqual('Two', root.get('two'))
        self.assertEqual(None, root.get('three'))
        self.assertEqual('foo', root.get('three', 'foo'))

    def test_attrib_clear(self):
        XML = self.etree.XML

        root = XML(_bytes('<doc one="One" two="Two"/>'))
        self.assertEqual('One', root.get('one'))
        self.assertEqual('Two', root.get('two'))
        root.attrib.clear()
        self.assertEqual(None, root.get('one'))
        self.assertEqual(None, root.get('two'))

    def test_attrib_set_clear(self):
        Element = self.etree.Element

        root = Element("root", one="One")
        root.set("two", "Two")
        self.assertEqual('One', root.get('one'))
        self.assertEqual('Two', root.get('two'))
        root.attrib.clear()
        self.assertEqual(None, root.get('one'))
        self.assertEqual(None, root.get('two'))

    def test_attrib_ns_clear(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        attribNS = '{http://foo/bar}x'

        parent = Element('parent')
        parent.set(attribNS, 'a')
        child = SubElement(parent, 'child')
        child.set(attribNS, 'b')

        self.assertEqual('a', parent.get(attribNS))
        self.assertEqual('b', child.get(attribNS))

        parent.clear()
        self.assertEqual(None, parent.get(attribNS))
        self.assertEqual('b', child.get(attribNS))

    def test_attrib_pop(self):
        ElementTree = self.etree.ElementTree

        f = BytesIO('<doc one="One" two="Two"/>')
        doc = ElementTree(file=f)
        root = doc.getroot()
        self.assertEqual('One', root.attrib['one'])
        self.assertEqual('Two', root.attrib['two'])

        self.assertEqual('One', root.attrib.pop('one'))

        self.assertEqual(None, root.attrib.get('one'))
        self.assertEqual('Two', root.attrib['two'])

    def test_attrib_pop_unknown(self):
        root = self.etree.XML(_bytes('<doc one="One" two="Two"/>'))
        self.assertRaises(KeyError, root.attrib.pop, 'NONE')

        self.assertEqual('One', root.attrib['one'])
        self.assertEqual('Two', root.attrib['two'])

    def test_attrib_pop_default(self):
        root = self.etree.XML(_bytes('<doc one="One" two="Two"/>'))
        self.assertEqual('Three', root.attrib.pop('three', 'Three'))

    def test_attrib_pop_empty_default(self):
        root = self.etree.XML(_bytes('<doc/>'))
        self.assertEqual('Three', root.attrib.pop('three', 'Three'))

    def test_attrib_pop_invalid_args(self):
        root = self.etree.XML(_bytes('<doc one="One" two="Two"/>'))
        self.assertRaises(TypeError, root.attrib.pop, 'One', None, None)

    def test_attribute_update_dict(self):
        XML = self.etree.XML

        root = XML(_bytes('<doc alpha="Alpha" beta="Beta"/>'))
        items = list(root.attrib.items())
        items.sort()
        self.assertEqual(
            [('alpha', 'Alpha'), ('beta', 'Beta')],
            items)

        root.attrib.update({'alpha' : 'test', 'gamma' : 'Gamma'})

        items = list(root.attrib.items())
        items.sort()
        self.assertEqual(
            [('alpha', 'test'), ('beta', 'Beta'), ('gamma', 'Gamma')],
            items)

    def test_attribute_update_sequence(self):
        XML = self.etree.XML

        root = XML(_bytes('<doc alpha="Alpha" beta="Beta"/>'))
        items = list(root.attrib.items())
        items.sort()
        self.assertEqual(
            [('alpha', 'Alpha'), ('beta', 'Beta')],
            items)

        root.attrib.update({'alpha' : 'test', 'gamma' : 'Gamma'}.items())

        items = list(root.attrib.items())
        items.sort()
        self.assertEqual(
            [('alpha', 'test'), ('beta', 'Beta'), ('gamma', 'Gamma')],
            items)

    def test_attribute_update_iter(self):
        XML = self.etree.XML

        root = XML(_bytes('<doc alpha="Alpha" beta="Beta"/>'))
        items = list(root.attrib.items())
        items.sort()
        self.assertEqual(
            [('alpha', 'Alpha'), ('beta', 'Beta')],
            items)

        root.attrib.update(iter({'alpha' : 'test', 'gamma' : 'Gamma'}.items()))

        items = list(root.attrib.items())
        items.sort()
        self.assertEqual(
            [('alpha', 'test'), ('beta', 'Beta'), ('gamma', 'Gamma')],
            items)

    def test_attribute_update_attrib(self):
        XML = self.etree.XML

        root = XML(_bytes('<doc alpha="Alpha" beta="Beta"/>'))
        items = list(root.attrib.items())
        items.sort()
        self.assertEqual(
            [('alpha', 'Alpha'), ('beta', 'Beta')],
                                                  items)

        other = XML(_bytes('<doc alpha="test" gamma="Gamma"/>'))
        root.attrib.update(other.attrib)

        items = list(root.attrib.items())
        items.sort()
        self.assertEqual(
            [('alpha', 'test'), ('beta', 'Beta'), ('gamma', 'Gamma')],
                                                                     items)

    def test_attribute_keys(self):
        XML = self.etree.XML

        root = XML(_bytes('<doc alpha="Alpha" beta="Beta" gamma="Gamma"/>'))
        keys = list(root.attrib.keys())
        keys.sort()
        self.assertEqual(['alpha', 'beta', 'gamma'], keys)

    def test_attribute_keys2(self):
        XML = self.etree.XML

        root = XML(_bytes('<doc alpha="Alpha" beta="Beta" gamma="Gamma"/>'))
        keys = list(root.keys())
        keys.sort()
        self.assertEqual(['alpha', 'beta', 'gamma'], keys)

    def test_attribute_items2(self):
        XML = self.etree.XML

        root = XML(_bytes('<doc alpha="Alpha" beta="Beta" gamma="Gamma"/>'))
        items = list(root.items())
        items.sort()
        self.assertEqual(
            [('alpha','Alpha'), ('beta','Beta'), ('gamma','Gamma')],
            items)

    def test_attribute_keys_ns(self):
        XML = self.etree.XML

        root = XML(_bytes('<foo bar="Bar" xmlns:ns="http://ns.codespeak.net/test" ns:baz="Baz" />'))
        keys = list(root.keys())
        keys.sort()
        self.assertEqual(['bar', '{http://ns.codespeak.net/test}baz'],
                          keys)

    def test_attribute_values(self):
        XML = self.etree.XML

        root = XML(_bytes('<doc alpha="Alpha" beta="Beta" gamma="Gamma"/>'))
        values = list(root.attrib.values())
        values.sort()
        self.assertEqual(['Alpha', 'Beta', 'Gamma'], values)

    def test_attribute_values_ns(self):
        XML = self.etree.XML

        root = XML(_bytes('<foo bar="Bar" xmlns:ns="http://ns.codespeak.net/test" ns:baz="Baz" />'))
        values = list(root.attrib.values())
        values.sort()
        self.assertEqual(
            ['Bar', 'Baz'], values)

    def test_attribute_items(self):
        XML = self.etree.XML

        root = XML(_bytes('<doc alpha="Alpha" beta="Beta" gamma="Gamma"/>'))
        items = list(root.attrib.items())
        items.sort()
        self.assertEqual([
            ('alpha', 'Alpha'),
            ('beta', 'Beta'),
            ('gamma', 'Gamma'),
            ], 
            items)

    def test_attribute_items_ns(self):
        XML = self.etree.XML

        root = XML(_bytes('<foo bar="Bar" xmlns:ns="http://ns.codespeak.net/test" ns:baz="Baz" />'))
        items = list(root.attrib.items())
        items.sort()
        self.assertEqual(
            [('bar', 'Bar'), ('{http://ns.codespeak.net/test}baz', 'Baz')],
            items)

    def test_attribute_str(self):
        XML = self.etree.XML

        expected = "{'{http://ns.codespeak.net/test}baz': 'Baz', 'bar': 'Bar'}"
        alternative = "{'bar': 'Bar', '{http://ns.codespeak.net/test}baz': 'Baz'}"

        root = XML(_bytes('<foo bar="Bar" xmlns:ns="http://ns.codespeak.net/test" ns:baz="Baz" />'))
        try:
            self.assertEqual(expected, str(root.attrib))
        except AssertionError:
            self.assertEqual(alternative, str(root.attrib))

    def test_attribute_contains(self):
        XML = self.etree.XML

        root = XML(_bytes('<foo bar="Bar" xmlns:ns="http://ns.codespeak.net/test" ns:baz="Baz" />'))
        self.assertEqual(
            True, 'bar' in root.attrib)
        self.assertEqual(
            False, 'baz' in root.attrib)
        self.assertEqual(
            False, 'hah' in root.attrib)
        self.assertEqual(
            True,
            '{http://ns.codespeak.net/test}baz' in root.attrib)

    def test_attribute_set(self):
        Element = self.etree.Element

        root = Element("root")
        root.set("attr", "TEST")
        self.assertEqual("TEST", root.get("attr"))

    def test_attrib_as_attrib(self):
        Element = self.etree.Element

        root = Element("root")
        root.set("attr", "TEST")
        self.assertEqual("TEST", root.attrib["attr"])

        root2 = Element("root2", root.attrib)
        self.assertEqual("TEST", root2.attrib["attr"])

    def test_attribute_iterator(self):
        XML = self.etree.XML

        root = XML(_bytes('<doc alpha="Alpha" beta="Beta" gamma="Gamma" />'))
        result = []
        for key in root.attrib:
            result.append(key)
        result.sort()
        self.assertEqual(['alpha', 'beta', 'gamma'], result)

    def test_attribute_manipulation(self):
        Element = self.etree.Element

        a = Element('a')
        a.attrib['foo'] = 'Foo'
        a.attrib['bar'] = 'Bar'
        self.assertEqual('Foo', a.attrib['foo'])
        del a.attrib['foo']
        self.assertRaises(KeyError, operator.getitem, a.attrib, 'foo')

    def test_del_attribute_ns(self):
        Element = self.etree.Element

        a = Element('a')
        a.attrib['{http://a/}foo'] = 'Foo'
        a.attrib['{http://a/}bar'] = 'Bar'
        self.assertEqual(None, a.get('foo'))
        self.assertEqual('Foo', a.get('{http://a/}foo'))
        self.assertEqual('Foo', a.attrib['{http://a/}foo'])

        self.assertRaises(KeyError, operator.delitem, a.attrib, 'foo')
        self.assertEqual('Foo', a.attrib['{http://a/}foo'])

        del a.attrib['{http://a/}foo']
        self.assertRaises(KeyError, operator.getitem, a.attrib, 'foo')

    def test_del_attribute_ns_parsed(self):
        XML = self.etree.XML

        a = XML(_bytes('<a xmlns:nsa="http://a/" nsa:foo="FooNS" foo="Foo" />'))

        self.assertEqual('Foo', a.attrib['foo'])
        self.assertEqual('FooNS', a.attrib['{http://a/}foo'])

        del a.attrib['foo']
        self.assertEqual('FooNS', a.attrib['{http://a/}foo'])
        self.assertRaises(KeyError, operator.getitem, a.attrib, 'foo')
        self.assertRaises(KeyError, operator.delitem, a.attrib, 'foo')

        del a.attrib['{http://a/}foo']
        self.assertRaises(KeyError, operator.getitem, a.attrib, '{http://a/}foo')
        self.assertRaises(KeyError, operator.getitem, a.attrib, 'foo')

        a = XML(_bytes('<a xmlns:nsa="http://a/" foo="Foo" nsa:foo="FooNS" />'))

        self.assertEqual('Foo', a.attrib['foo'])
        self.assertEqual('FooNS', a.attrib['{http://a/}foo'])

        del a.attrib['foo']
        self.assertEqual('FooNS', a.attrib['{http://a/}foo'])
        self.assertRaises(KeyError, operator.getitem, a.attrib, 'foo')

        del a.attrib['{http://a/}foo']
        self.assertRaises(KeyError, operator.getitem, a.attrib, '{http://a/}foo')
        self.assertRaises(KeyError, operator.getitem, a.attrib, 'foo')

    def test_XML(self):
        XML = self.etree.XML

        root = XML(_bytes('<doc>This is a text.</doc>'))
        self.assertEqual(0, len(root))
        self.assertEqual('This is a text.', root.text)

    def test_XMLID(self):
        XMLID = self.etree.XMLID
        XML   = self.etree.XML
        xml_text = _bytes('''
        <document>
          <h1 id="chapter1">...</h1>
          <p id="note1" class="note">...</p>
          <p>Regular paragraph.</p>
          <p xml:id="xmlid">XML:ID paragraph.</p>
          <p id="warn1" class="warning">...</p>
        </document>
        ''')

        root, dic = XMLID(xml_text)
        root2 = XML(xml_text)
        self.assertEqual(self._writeElement(root),
                          self._writeElement(root2))
        expected = {
            "chapter1" : root[0],
            "note1"    : root[1],
            "warn1"    : root[4]
            }
        self.assertEqual(dic, expected)

    def test_fromstring(self):
        fromstring = self.etree.fromstring

        root = fromstring('<doc>This is a text.</doc>')
        self.assertEqual(0, len(root))
        self.assertEqual('This is a text.', root.text)

    required_versions_ET['test_fromstringlist'] = (1,3)
    def test_fromstringlist(self):
        fromstringlist = self.etree.fromstringlist

        root = fromstringlist(["<do", "c>T", "hi", "s is",
                               " a text.<", "/doc", ">"])
        self.assertEqual(0, len(root))
        self.assertEqual('This is a text.', root.text)

    required_versions_ET['test_fromstringlist_characters'] = (1,3)
    def test_fromstringlist_characters(self):
        fromstringlist = self.etree.fromstringlist

        root = fromstringlist(list('<doc>This is a text.</doc>'))
        self.assertEqual(0, len(root))
        self.assertEqual('This is a text.', root.text)

    required_versions_ET['test_fromstringlist_single'] = (1,3)
    def test_fromstringlist_single(self):
        fromstringlist = self.etree.fromstringlist

        root = fromstringlist(['<doc>This is a text.</doc>'])
        self.assertEqual(0, len(root))
        self.assertEqual('This is a text.', root.text)

    def test_iselement(self):
        iselement = self.etree.iselement
        Element = self.etree.Element
        ElementTree = self.etree.ElementTree
        XML = self.etree.XML
        Comment = self.etree.Comment
        ProcessingInstruction = self.etree.ProcessingInstruction

        el = Element('hoi')
        self.assertTrue(iselement(el))

        el2 = XML(_bytes('<foo/>'))
        self.assertTrue(iselement(el2))

        tree = ElementTree(element=Element('dag'))
        self.assertTrue(not iselement(tree))
        self.assertTrue(iselement(tree.getroot()))

        c = Comment('test')
        self.assertTrue(iselement(c))

        p = ProcessingInstruction("test", "some text")
        self.assertTrue(iselement(p))

    def test_iteration(self):
        XML = self.etree.XML

        root = XML(_bytes('<doc><one/><two>Two</two>Hm<three/></doc>'))
        result = []
        for el in root:
            result.append(el.tag)
        self.assertEqual(['one', 'two', 'three'], result)

    def test_iteration_empty(self):
        XML = self.etree.XML

        root = XML(_bytes('<doc></doc>'))
        result = []
        for el in root:
            result.append(el.tag)
        self.assertEqual([], result)

    def test_iteration_text_only(self):
        XML = self.etree.XML

        root = XML(_bytes('<doc>Text</doc>'))
        result = []
        for el in root:
            result.append(el.tag)
        self.assertEqual([], result)

    def test_iteration_set_tail_empty(self):
        # this would cause a crash in the past
        fromstring = self.etree.fromstring
        root = fromstring('<html><p></p>x</html>')
        for elem in root:
            elem.tail = ''

    def test_iteration_clear_tail(self):
        # this would cause a crash in the past
        fromstring = self.etree.fromstring
        root = fromstring('<html><p></p>x</html>')
        for elem in root:
            elem.tail = None

    def test_iteration_reversed(self):
        XML = self.etree.XML
        root = XML(_bytes('<doc><one/><two>Two</two>Hm<three/></doc>'))
        result = []
        for el in reversed(root):
            result.append(el.tag)
        self.assertEqual(['three', 'two', 'one'], result)

    def test_iteration_subelement(self):
        XML = self.etree.XML

        root = XML(_bytes('<doc><one/><two>Two</two>Hm<three/></doc>'))
        result = []
        add = True
        for el in root:
            result.append(el.tag)
            if add:
                self.etree.SubElement(root, 'four')
                add = False
        self.assertEqual(['one', 'two', 'three', 'four'], result)

    def test_iteration_del_child(self):
        XML = self.etree.XML

        root = XML(_bytes('<doc><one/><two>Two</two>Hm<three/></doc>'))
        result = []
        for el in root:
            result.append(el.tag)
            del root[-1]
        self.assertEqual(['one', 'two'], result)

    def test_iteration_double(self):
        XML = self.etree.XML

        root = XML(_bytes('<doc><one/><two/></doc>'))
        result = []
        for el0 in root:
            result.append(el0.tag)
            for el1 in root:
                result.append(el1.tag)
        self.assertEqual(['one','one', 'two', 'two', 'one', 'two'], result)

    required_versions_ET['test_itertext'] = (1,3)
    def test_itertext(self):
        # ET 1.3+
        XML = self.etree.XML
        root = XML(_bytes("<root>RTEXT<a></a>ATAIL<b/><c>CTEXT</c>CTAIL</root>"))

        text = list(root.itertext())
        self.assertEqual(["RTEXT", "ATAIL", "CTEXT", "CTAIL"],
                          text)

    required_versions_ET['test_itertext_child'] = (1,3)
    def test_itertext_child(self):
        # ET 1.3+
        XML = self.etree.XML
        root = XML(_bytes("<root>RTEXT<a></a>ATAIL<b/><c>CTEXT</c>CTAIL</root>"))

        text = list(root[2].itertext())
        self.assertEqual(["CTEXT"],
                          text)

    def test_findall(self):
        XML = self.etree.XML
        root = XML(_bytes('<a><b><c/></b><b/><c><b/></c></a>'))
        self.assertEqual(len(list(root.findall("c"))), 1)
        self.assertEqual(len(list(root.findall(".//c"))), 2)
        self.assertEqual(len(list(root.findall(".//b"))), 3)
        self.assertEqual(len(list(root.findall(".//b"))[0]), 1)
        self.assertEqual(len(list(root.findall(".//b"))[1]), 0)
        self.assertEqual(len(list(root.findall(".//b"))[2]), 0)

    def test_findall_ns(self):
        XML = self.etree.XML
        root = XML(_bytes('<a xmlns:x="X" xmlns:y="Y"><x:b><c/></x:b><b/><c><x:b/><b/></c><b/></a>'))
        self.assertEqual(len(list(root.findall(".//{X}b"))), 2)
        self.assertEqual(len(list(root.findall(".//b"))), 3)
        self.assertEqual(len(list(root.findall("b"))), 2)

    @et_needs_pyversion(3, 8, 0, 'alpha', 4)
    def test_findall_wildcard(self):
        def summarize_list(l):
            return [el.tag for el in l]

        root = self.etree.XML('''
            <a xmlns:x="X" xmlns:y="Y">
                <x:b><c/></x:b>
                <b/>
                <c><x:b/><b/></c><y:b/>
            </a>''')
        root.append(self.etree.Comment('test'))

        self.assertEqual(summarize_list(root.findall("{*}b")),
                         ['{X}b', 'b', '{Y}b'])
        self.assertEqual(summarize_list(root.findall("{*}c")),
                         ['c'])
        self.assertEqual(summarize_list(root.findall("{X}*")),
                         ['{X}b'])
        self.assertEqual(summarize_list(root.findall("{Y}*")),
                         ['{Y}b'])
        self.assertEqual(summarize_list(root.findall("{}*")),
                         ['b', 'c'])
        self.assertEqual(summarize_list(root.findall("{}b")),  # only for consistency
                         ['b'])
        self.assertEqual(summarize_list(root.findall("{}b")),
                         summarize_list(root.findall("b")))
        self.assertEqual(summarize_list(root.findall("{*}*")),
                         ['{X}b', 'b', 'c', '{Y}b'])
        self.assertEqual(summarize_list(root.findall("{*}*")
                         + ([] if self.etree is etree else [root[-1]])),
                         summarize_list(root.findall("*")))

        self.assertEqual(summarize_list(root.findall(".//{*}b")),
                         ['{X}b', 'b', '{X}b', 'b', '{Y}b'])
        self.assertEqual(summarize_list(root.findall(".//{*}c")),
                         ['c', 'c'])
        self.assertEqual(summarize_list(root.findall(".//{X}*")),
                         ['{X}b', '{X}b'])
        self.assertEqual(summarize_list(root.findall(".//{Y}*")),
                         ['{Y}b'])
        self.assertEqual(summarize_list(root.findall(".//{}*")),
                         ['c', 'b', 'c', 'b'])
        self.assertEqual(summarize_list(root.findall(".//{}b")),
                         ['b', 'b'])

    def test_element_with_attributes_keywords(self):
        Element = self.etree.Element

        el = Element('tag', foo='Foo', bar='Bar')
        self.assertEqual('Foo', el.attrib['foo'])
        self.assertEqual('Bar', el.attrib['bar'])

    def test_element_with_attributes(self):
        Element = self.etree.Element

        el = Element('tag', {'foo': 'Foo', 'bar': 'Bar'})
        self.assertEqual('Foo', el.attrib['foo'])
        self.assertEqual('Bar', el.attrib['bar'])

    def test_element_with_attributes_extra(self):
        Element = self.etree.Element

        el = Element('tag', {'foo': 'Foo', 'bar': 'Bar'}, baz='Baz')
        self.assertEqual('Foo', el.attrib['foo'])
        self.assertEqual('Bar', el.attrib['bar'])
        self.assertEqual('Baz', el.attrib['baz'])

    def test_element_with_attributes_extra_duplicate(self):
        Element = self.etree.Element

        el = Element('tag', {'foo': 'Foo', 'bar': 'Bar'}, bar='Baz')
        self.assertEqual('Foo', el.attrib['foo'])
        self.assertEqual('Baz', el.attrib['bar'])

    def test_element_with_attributes_ns(self):
        Element = self.etree.Element

        el = Element('tag', {'{ns1}foo':'Foo', '{ns2}bar':'Bar'})
        self.assertEqual('Foo', el.attrib['{ns1}foo'])
        self.assertEqual('Bar', el.attrib['{ns2}bar'])

    def test_subelement_with_attributes(self):
        Element =  self.etree.Element
        SubElement = self.etree.SubElement

        el = Element('tag')
        SubElement(el, 'foo', {'foo':'Foo'}, baz="Baz")
        self.assertEqual("Baz", el[0].attrib['baz'])
        self.assertEqual('Foo', el[0].attrib['foo'])

    def test_subelement_with_attributes_ns(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        el = Element('tag')
        SubElement(el, 'foo', {'{ns1}foo':'Foo', '{ns2}bar':'Bar'})
        self.assertEqual('Foo', el[0].attrib['{ns1}foo'])
        self.assertEqual('Bar', el[0].attrib['{ns2}bar'])

    def test_write(self):
        ElementTree = self.etree.ElementTree
        XML = self.etree.XML

        for i in range(10):
            f = BytesIO() 
            root = XML(_bytes('<doc%s>This is a test.</doc%s>' % (i, i)))
            tree = ElementTree(element=root)
            tree.write(f)
            data = f.getvalue()
            self.assertEqual(
                _bytes('<doc%s>This is a test.</doc%s>' % (i, i)),
                canonicalize(data))

    required_versions_ET['test_write_method_html'] = (1,3)
    def test_write_method_html(self):
        ElementTree = self.etree.ElementTree
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        html = Element('html')
        body = SubElement(html, 'body')
        p = SubElement(body, 'p')
        p.text = "html"
        SubElement(p, 'br').tail = "test"

        tree = ElementTree(element=html)
        f = BytesIO() 
        tree.write(f, method="html")
        data = f.getvalue().replace(_bytes('\n'),_bytes(''))

        self.assertEqual(_bytes('<html><body><p>html<br>test</p></body></html>'),
                          data)

    required_versions_ET['test_write_method_text'] = (1,3)
    def test_write_method_text(self):
        ElementTree = self.etree.ElementTree
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        a.text = "A"
        a.tail = "tail"
        b = SubElement(a, 'b')
        b.text = "B"
        b.tail = "TAIL"
        c = SubElement(a, 'c')
        c.text = "C"

        tree = ElementTree(element=a)
        f = BytesIO() 
        tree.write(f, method="text")
        data = f.getvalue()

        self.assertEqual(_bytes('ABTAILCtail'),
                          data)

    def test_write_fail(self):
        ElementTree = self.etree.ElementTree
        XML = self.etree.XML

        tree = ElementTree( XML(_bytes('<doc>This is a test.</doc>')) )
        self.assertRaises(IOError, tree.write,
                          "definitely////\\-\\nonexisting\\-\\////FILE")

    # this could trigger a crash, apparently because the document
    # reference was prematurely garbage collected
    def test_crash(self):
        Element = self.etree.Element

        element = Element('tag')
        for i in range(10):
            element.attrib['key'] = 'value'
            value = element.attrib['key']
            self.assertEqual(value, 'value')

    # from doctest; for some reason this caused crashes too
    def test_write_ElementTreeDoctest(self):
        Element = self.etree.Element
        ElementTree = self.etree.ElementTree

        f = BytesIO()
        for i in range(10):
            element = Element('tag%s' % i)
            self._check_element(element)
            tree = ElementTree(element)
            tree.write(f)
            self._check_element_tree(tree)

    def test_subelement_reference(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        el = Element('foo')
        el2 = SubElement(el, 'bar')
        el3 = SubElement(el2, 'baz')

        al = Element('foo2')
        al2 = SubElement(al, 'bar2')
        al3 = SubElement(al2, 'baz2')

        # now move al2 into el
        el.append(al2)

        # now change al3 directly
        al3.text = 'baz2-modified'

        # it should have changed through this route too
        self.assertEqual(
            'baz2-modified',
            el[1][0].text)

    def test_set_text(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        a.text = 'hoi'
        self.assertEqual(
            'hoi',
            a.text)
        self.assertEqual(
            'b',
            a[0].tag)

    def test_set_text2(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        a.text = 'hoi'
        b = SubElement(a ,'b')
        self.assertEqual(
            'hoi',
            a.text)
        self.assertEqual(
            'b',
            a[0].tag)

    def test_set_text_none(self):
        Element = self.etree.Element

        a = Element('a')

        a.text = 'foo'
        a.text = None

        self.assertEqual(
            None,
            a.text)
        self.assertXML(_bytes('<a></a>'), a)

    def test_set_text_empty(self):
        Element = self.etree.Element

        a = Element('a')
        self.assertEqual(None, a.text)

        a.text = ''
        self.assertEqual('', a.text)
        self.assertXML(_bytes('<a></a>'), a)

    def test_tail1(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        a.tail = 'dag'
        self.assertEqual('dag',
                          a.tail)
        b = SubElement(a, 'b')
        b.tail = 'hoi'
        self.assertEqual('hoi',
                          b.tail)
        self.assertEqual('dag',
                          a.tail)

    def test_tail_append(self):
        Element = self.etree.Element

        a = Element('a')
        b = Element('b')
        b.tail = 'b_tail'
        a.append(b)
        self.assertEqual('b_tail',
                          b.tail)

    def test_tail_set_twice(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        b.tail = 'foo'
        b.tail = 'bar'
        self.assertEqual('bar',
                          b.tail)
        self.assertXML(_bytes('<a><b></b>bar</a>'), a)

    def test_tail_set_none(self):
        Element = self.etree.Element
        a = Element('a')
        a.tail = 'foo'
        a.tail = None
        self.assertEqual(
            None,
            a.tail)
        self.assertXML(_bytes('<a></a>'), a)

    required_versions_ET['test_extend'] = (1,3)
    def test_extend(self):
        root = self.etree.Element('foo')
        for i in range(3):
            element = self.etree.SubElement(root, 'a%s' % i)
            element.text = "text%d" % i
            element.tail = "tail%d" % i

        elements = []
        for i in range(3):
            new_element = self.etree.Element("test%s" % i)
            new_element.text = "TEXT%s" % i
            new_element.tail = "TAIL%s" % i
            elements.append(new_element)

        root.extend(elements)

        self.assertEqual(
            ["a0", "a1", "a2", "test0", "test1", "test2"],
            [ el.tag for el in root ])
        self.assertEqual(
            ["text0", "text1", "text2", "TEXT0", "TEXT1", "TEXT2"],
            [ el.text for el in root ])
        self.assertEqual(
            ["tail0", "tail1", "tail2", "TAIL0", "TAIL1", "TAIL2"],
            [ el.tail for el in root ])

    def test_comment(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement
        Comment = self.etree.Comment

        a = Element('a')
        a.append(Comment('foo'))
        self.assertEqual(a[0].tag, Comment)
        self.assertEqual(a[0].text, 'foo')

    # ElementTree < 1.3 adds whitespace around comments
    required_versions_ET['test_comment_text'] = (1,3)
    def test_comment_text(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement
        Comment = self.etree.Comment
        tostring = self.etree.tostring

        a = Element('a')
        a.append(Comment('foo'))
        self.assertEqual(a[0].text, 'foo')

        self.assertEqual(
            _bytes('<a><!--foo--></a>'),
            tostring(a))

        a[0].text = "TEST"
        self.assertEqual(a[0].text, 'TEST')

        self.assertEqual(
            _bytes('<a><!--TEST--></a>'),
            tostring(a))

    # ElementTree < 1.3 adds whitespace around comments
    required_versions_ET['test_comment_whitespace'] = (1,3)
    def test_comment_whitespace(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement
        Comment = self.etree.Comment
        tostring = self.etree.tostring

        a = Element('a')
        a.append(Comment(' foo  '))
        self.assertEqual(a[0].text, ' foo  ')
        self.assertEqual(
            _bytes('<a><!-- foo  --></a>'),
            tostring(a))

    def test_comment_nonsense(self):
        Comment = self.etree.Comment
        c = Comment('foo')
        self.assertEqual({}, c.attrib)
        self.assertEqual([], list(c.keys()))
        self.assertEqual([], list(c.items()))
        self.assertEqual(None, c.get('hoi'))
        self.assertEqual(0, len(c))
        # should not iterate
        for i in c:
            pass

    def test_pi(self):
        # lxml.etree separates target and text
        Element = self.etree.Element
        SubElement = self.etree.SubElement
        ProcessingInstruction = self.etree.ProcessingInstruction

        a = Element('a')
        a.append(ProcessingInstruction('foo', 'some more text'))
        self.assertEqual(a[0].tag, ProcessingInstruction)
        self.assertXML(_bytes("<a><?foo some more text?></a>"),
                       a)

    def test_processinginstruction(self):
        # lxml.etree separates target and text
        Element = self.etree.Element
        SubElement = self.etree.SubElement
        ProcessingInstruction = self.etree.PI

        a = Element('a')
        a.append(ProcessingInstruction('foo', 'some more text'))
        self.assertEqual(a[0].tag, ProcessingInstruction)
        self.assertXML(_bytes("<a><?foo some more text?></a>"),
                       a)

    def test_pi_nonsense(self):
        ProcessingInstruction = self.etree.ProcessingInstruction
        pi = ProcessingInstruction('foo')
        self.assertEqual({}, pi.attrib)
        self.assertEqual([], list(pi.keys()))
        self.assertEqual([], list(pi.items()))
        self.assertEqual(None, pi.get('hoi'))
        self.assertEqual(0, len(pi))
        # should not iterate
        for i in pi:
            pass

    def test_setitem(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        c = Element('c')
        a[0] = c
        self.assertEqual(
            c,
            a[0])
        self.assertXML(_bytes('<a><c></c></a>'),
                       a)
        self.assertXML(_bytes('<b></b>'),
                       b)

    def test_setitem2(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        for i in range(5):
            b = SubElement(a, 'b%s' % i)
            c = SubElement(b, 'c')
        for i in range(5):
            d = Element('d')
            e = SubElement(d, 'e')
            a[i] = d
        self.assertXML(
            _bytes('<a><d><e></e></d><d><e></e></d><d><e></e></d><d><e></e></d><d><e></e></d></a>'),
            a)
        self.assertXML(_bytes('<c></c>'),
                       c)

    def test_setitem_replace(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        SubElement(a, 'b')
        d = Element('d')
        a[0] = d
        self.assertXML(_bytes('<a><d></d></a>'), a)

    def test_setitem_indexerror(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')

        self.assertRaises(IndexError, operator.setitem, a, 1, Element('c'))

    def test_setitem_tail(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        b.tail = 'B2'
        c = Element('c')
        c.tail = 'C2'

        a[0] = c
        self.assertXML(
            _bytes('<a><c></c>C2</a>'),
            a)

    def test_tag_write(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')

        a.tag = 'c'

        self.assertEqual(
            'c',
            a.tag)

        self.assertXML(
            _bytes('<c><b></b></c>'),
            a)

    def test_tag_reset_ns(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement
        tostring = self.etree.tostring

        a = Element('{a}a')
        b1 = SubElement(a, '{a}b')
        b2 = SubElement(a, '{b}b')

        self.assertEqual('{a}b',  b1.tag)

        b1.tag = 'c'

        # can't use C14N here!
        self.assertEqual('c', b1.tag)
        self.assertEqual(_bytes('<c'), tostring(b1)[:2])
        self.assertTrue(_bytes('<c') in tostring(a))

    def test_tag_reset_root_ns(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement
        tostring = self.etree.tostring

        a = Element('{a}a')
        b1 = SubElement(a, '{a}b')
        b2 = SubElement(a, '{b}b')

        a.tag = 'c'

        self.assertEqual(
            'c',
            a.tag)

        # can't use C14N here!
        self.assertEqual('c',  a.tag)
        self.assertEqual(_bytes('<c'), tostring(a)[:2])

    def test_tag_str_subclass(self):
        Element = self.etree.Element

        class strTest(str):
            pass

        a = Element("a")
        a.tag = strTest("TAG")
        self.assertXML(_bytes('<TAG></TAG>'),
                       a)

    def test_delitem(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        c = SubElement(a, 'c')
        d = SubElement(a, 'd')

        del a[1]
        self.assertXML(
            _bytes('<a><b></b><d></d></a>'),
            a)

        del a[0]
        self.assertXML(
            _bytes('<a><d></d></a>'),
            a)

        del a[0]
        self.assertXML(
            _bytes('<a></a>'),
            a)
        # move deleted element into other tree afterwards
        other = Element('other')
        other.append(c)
        self.assertXML(
            _bytes('<other><c></c></other>'),
            other)

    def test_del_insert(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        bs = SubElement(b, 'bs')
        c = SubElement(a, 'c')
        cs = SubElement(c, 'cs')

        el = a[0]
        self.assertXML(
            _bytes('<a><b><bs></bs></b><c><cs></cs></c></a>'),
            a)
        self.assertXML(_bytes('<b><bs></bs></b>'), b)
        self.assertXML(_bytes('<c><cs></cs></c>'), c)

        del a[0]
        self.assertXML(
            _bytes('<a><c><cs></cs></c></a>'),
            a)
        self.assertXML(_bytes('<b><bs></bs></b>'), b)
        self.assertXML(_bytes('<c><cs></cs></c>'), c)

        a.insert(0, el)
        self.assertXML(
            _bytes('<a><b><bs></bs></b><c><cs></cs></c></a>'),
            a)
        self.assertXML(_bytes('<b><bs></bs></b>'), b)
        self.assertXML(_bytes('<c><cs></cs></c>'), c)

    def test_del_setitem(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        bs = SubElement(b, 'bs')
        c = SubElement(a, 'c')
        cs = SubElement(c, 'cs')

        el = a[0]
        del a[0]
        a[0] = el
        self.assertXML(
            _bytes('<a><b><bs></bs></b></a>'),
            a)
        self.assertXML(_bytes('<b><bs></bs></b>'), b)
        self.assertXML(_bytes('<c><cs></cs></c>'), c)

    def test_del_setslice(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        bs = SubElement(b, 'bs')
        c = SubElement(a, 'c')
        cs = SubElement(c, 'cs')

        el = a[0]
        del a[0]
        a[0:0] = [el]
        self.assertXML(
            _bytes('<a><b><bs></bs></b><c><cs></cs></c></a>'),
            a)
        self.assertXML(_bytes('<b><bs></bs></b>'), b)
        self.assertXML(_bytes('<c><cs></cs></c>'), c)

    def test_replace_slice_tail(self):
        XML = self.etree.XML
        a = XML(_bytes('<a><b></b>B2<c></c>C2</a>'))
        b, c = a

        a[:] = []

        self.assertEqual("B2", b.tail)
        self.assertEqual("C2", c.tail)

    def test_merge_namespaced_subtree_as_slice(self):
        XML = self.etree.XML
        root = XML(_bytes(
            '<foo><bar xmlns:baz="http://huhu"><puh><baz:bump1 /><baz:bump2 /></puh></bar></foo>'))
        root[:] = root.findall('.//puh') # delete bar from hierarchy

        # previously, this lost a namespace declaration on bump2
        result = self.etree.tostring(root)
        foo = self.etree.fromstring(result)

        self.assertEqual('puh', foo[0].tag)
        self.assertEqual('{http://huhu}bump1', foo[0][0].tag)
        self.assertEqual('{http://huhu}bump2', foo[0][1].tag)

    def test_delitem_tail_dealloc(self):
        ElementTree = self.etree.ElementTree
        f = BytesIO('<a><b></b>B2<c></c>C2</a>')
        doc = ElementTree(file=f)
        a = doc.getroot()
        del a[0]
        self.assertXML(
            _bytes('<a><c></c>C2</a>'),
            a)

    def test_delitem_tail(self):
        ElementTree = self.etree.ElementTree
        f = BytesIO('<a><b></b>B2<c></c>C2</a>')
        doc = ElementTree(file=f)
        a = doc.getroot()
        b, c = a
        del a[0]
        self.assertXML(
            _bytes('<a><c></c>C2</a>'),
            a)
        self.assertEqual("B2", b.tail)
        self.assertEqual("C2", c.tail)

    def test_clear(self):
        Element = self.etree.Element

        a = Element('a')
        a.text = 'foo'
        a.tail = 'bar'
        a.set('hoi', 'dag')
        a.clear()
        self.assertEqual(None, a.text)
        self.assertEqual(None, a.tail)
        self.assertEqual(None, a.get('hoi'))
        self.assertEqual('a', a.tag)

    def test_clear_sub(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        a.text = 'foo'
        a.tail = 'bar'
        a.set('hoi', 'dag')
        b = SubElement(a, 'b')
        c = SubElement(b, 'c')
        a.clear()
        self.assertEqual(None, a.text)
        self.assertEqual(None, a.tail)
        self.assertEqual(None, a.get('hoi'))
        self.assertEqual('a', a.tag)
        self.assertEqual(0, len(a))
        self.assertXML(_bytes('<a></a>'),
                       a)
        self.assertXML(_bytes('<b><c></c></b>'),
                       b)

    def test_clear_tail(self):
        ElementTree = self.etree.ElementTree
        f = BytesIO('<a><b></b>B2<c></c>C2</a>')
        doc = ElementTree(file=f)
        a = doc.getroot()
        a.clear()
        self.assertXML(
            _bytes('<a></a>'),
            a)

    def test_insert(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        c = SubElement(a, 'c')
        d = Element('d')
        a.insert(0, d)

        self.assertEqual(
            d,
            a[0])

        self.assertXML(
            _bytes('<a><d></d><b></b><c></c></a>'),
            a)

        e = Element('e')
        a.insert(2, e)
        self.assertEqual(
            e,
            a[2])
        self.assertXML(
            _bytes('<a><d></d><b></b><e></e><c></c></a>'),
            a)

    def test_insert_name_interning(self):
        # See GH#268 / LP#1773749.
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        # Use unique names to make sure they are new in the tag name dict.
        import uuid
        names = dict((k, 'tag-' + str(uuid.uuid4())) for k in 'abcde')

        a = Element(names['a'])
        b = SubElement(a, names['b'])
        c = SubElement(a, names['c'])
        d = Element(names['d'])
        a.insert(0, d)

        self.assertEqual(
            d,
            a[0])

        self.assertXML(
            _bytes('<%(a)s><%(d)s></%(d)s><%(b)s></%(b)s><%(c)s></%(c)s></%(a)s>' % names),
            a)

        e = Element(names['e'])
        a.insert(2, e)
        self.assertEqual(
            e,
            a[2])
        self.assertXML(
            _bytes('<%(a)s><%(d)s></%(d)s><%(b)s></%(b)s><%(e)s></%(e)s><%(c)s></%(c)s></%(a)s>' % names),
            a)

    def test_insert_beyond_index(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        c = Element('c')

        a.insert(2, c)
        self.assertEqual(
            c,
            a[1])
        self.assertXML(
            _bytes('<a><b></b><c></c></a>'),
            a)

    def test_insert_negative(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        c = SubElement(a, 'c')

        d = Element('d')
        a.insert(-1, d)
        self.assertEqual(
            d,
            a[-2])
        self.assertXML(
            _bytes('<a><b></b><d></d><c></c></a>'),
            a)

    def test_insert_tail(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')

        c = Element('c')
        c.tail = 'C2'

        a.insert(0, c)
        self.assertXML(
            _bytes('<a><c></c>C2<b></b></a>'),
            a)

    def test_remove(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        c = SubElement(a, 'c')

        a.remove(b)
        self.assertEqual(
            c,
            a[0])
        self.assertXML(
            _bytes('<a><c></c></a>'),
            a)

    def test_remove_ns(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('{http://test}a')
        b = SubElement(a, '{http://test}b')
        c = SubElement(a, '{http://test}c')

        a.remove(b)
        self.assertXML(
            _bytes('<ns0:a xmlns:ns0="http://test"><ns0:c></ns0:c></ns0:a>'),
            a)
        self.assertXML(
            _bytes('<ns0:b xmlns:ns0="http://test"></ns0:b>'),
            b)

    def test_remove_nonexisting(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        c = SubElement(a, 'c')
        d = Element('d')
        self.assertRaises(
            ValueError, a.remove, d)

    def test_remove_tail(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        b.tail = 'b2'
        a.remove(b)
        self.assertXML(
            _bytes('<a></a>'),
            a)
        self.assertEqual('b2', b.tail)

    def test_remove_while_iterating(self):
        # There is no guarantee that this "works", but it should
        # remove at least one child and not crash.
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        SubElement(a, 'b')
        SubElement(a, 'c')
        SubElement(a, 'd')
        for el in a:
            a.remove(el)
        self.assertLess(len(a), 3)

    def test_makeelement(self):
        Element = self.etree.Element

        a = Element('a')
        b = a.makeelement('c', {'hoi':'dag'})
        self.assertXML(
            _bytes('<c hoi="dag"></c>'),
            b)

    required_versions_ET['test_iter'] = (1,3)
    def test_iter(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        c = SubElement(a, 'c')
        d = SubElement(b, 'd')
        e = SubElement(c, 'e')

        self.assertEqual(
            [a, b, d, c, e],
            list(a.iter()))
        self.assertEqual(
            [d],
            list(d.iter()))

    def test_iter_remove_tail(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        a.text = 'a'
        a.tail = 'a1' * 100
        b = SubElement(a, 'b')
        b.text = 'b'
        b.tail = 'b1' * 100
        c = SubElement(a, 'c')
        c.text = 'c'
        c.tail = 'c1' * 100
        d = SubElement(b, 'd')
        d.text = 'd'
        d.tail = 'd1' * 100
        e = SubElement(c, 'e')
        e.text = 'e'
        e.tail = 'e1' * 100

        for el in a.iter():
            el.tail = None
        el = None

        self.assertEqual(
            [None] * 5,
            [el.tail for el in a.iter()])

    def test_getslice(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        c = SubElement(a, 'c')
        d = SubElement(a, 'd')

        self.assertEqual(
            [b, c],
            a[0:2])
        self.assertEqual(
            [b, c, d],
            a[:])
        self.assertEqual(
            [b, c, d],
            a[:10])
        self.assertEqual(
            [b],
            a[0:1])
        self.assertEqual(
            [],
            a[10:12])

    def test_getslice_negative(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        c = SubElement(a, 'c')
        d = SubElement(a, 'd')

        self.assertEqual(
            [d],
            a[-1:])
        self.assertEqual(
            [c, d],
            a[-2:])
        self.assertEqual(
            [c],
            a[-2:-1])
        self.assertEqual(
            [b, c],
            a[-3:-1])
        self.assertEqual(
            [b, c],
            a[-3:2])

    def test_getslice_step(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        c = SubElement(a, 'c')
        d = SubElement(a, 'd')
        e = SubElement(a, 'e')

        self.assertEqual(
            [e,d,c,b],
            a[::-1])
        self.assertEqual(
            [b,d],
            a[::2])
        self.assertEqual(
            [e,c],
            a[::-2])
        self.assertEqual(
            [d,c],
            a[-2:0:-1])
        self.assertEqual(
            [e],
            a[:1:-2])

    def test_getslice_text(self):
        ElementTree = self.etree.ElementTree

        f = BytesIO('<a><b>B</b>B1<c>C</c>C1</a>')
        doc = ElementTree(file=f)
        a = doc.getroot()
        b = a[0]
        c = a[1]
        self.assertEqual(
            [b, c],
            a[:])
        self.assertEqual(
            [b],
            a[0:1])
        self.assertEqual(
            [c],
            a[1:])

    def test_comment_getitem_getslice(self):
        Element = self.etree.Element
        Comment = self.etree.Comment
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        foo = Comment('foo')
        a.append(foo)
        c = SubElement(a, 'c')
        self.assertEqual(
            [b, foo, c],
            a[:])
        self.assertEqual(
            foo,
            a[1])
        a[1] = new = Element('new')
        self.assertEqual(
            new,
            a[1])
        self.assertXML(
            _bytes('<a><b></b><new></new><c></c></a>'),
            a)

    def test_delslice(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        c = SubElement(a, 'c')
        d = SubElement(a, 'd')
        e = SubElement(a, 'e')

        del a[1:3]
        self.assertEqual(
            [b, e],
            list(a))

    def test_delslice_negative1(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        c = SubElement(a, 'c')
        d = SubElement(a, 'd')
        e = SubElement(a, 'e')

        del a[1:-1]
        self.assertEqual(
            [b, e],
            list(a))

    def test_delslice_negative2(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        c = SubElement(a, 'c')
        d = SubElement(a, 'd')
        e = SubElement(a, 'e')

        del a[-3:-1]
        self.assertEqual(
            [b, e],
            list(a))

    def test_delslice_step(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        c = SubElement(a, 'c')
        d = SubElement(a, 'd')
        e = SubElement(a, 'e')

        del a[1::2]
        self.assertEqual(
            [b, d],
            list(a))

    def test_delslice_step_negative(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        c = SubElement(a, 'c')
        d = SubElement(a, 'd')
        e = SubElement(a, 'e')

        del a[::-1]
        self.assertEqual(
            [],
            list(a))

    def test_delslice_step_negative2(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        c = SubElement(a, 'c')
        d = SubElement(a, 'd')
        e = SubElement(a, 'e')

        del a[::-2]
        self.assertEqual(
            [b, d],
            list(a))

    def test_delslice_child_tail_dealloc(self):
        ElementTree = self.etree.ElementTree
        f = BytesIO('<a><b></b>B2<c></c>C2<d></d>D2<e></e>E2</a>')
        doc = ElementTree(file=f)
        a = doc.getroot()
        del a[1:3]
        self.assertXML(
            _bytes('<a><b></b>B2<e></e>E2</a>'),
            a)

    def test_delslice_child_tail(self):
        ElementTree = self.etree.ElementTree
        f = BytesIO('<a><b></b>B2<c></c>C2<d></d>D2<e></e>E2</a>')
        doc = ElementTree(file=f)
        a = doc.getroot()
        b, c, d, e = a
        del a[1:3]
        self.assertXML(
            _bytes('<a><b></b>B2<e></e>E2</a>'),
            a)
        self.assertEqual("B2", b.tail)
        self.assertEqual("C2", c.tail)
        self.assertEqual("D2", d.tail)
        self.assertEqual("E2", e.tail)

    def test_delslice_tail(self):
        XML = self.etree.XML
        a = XML(_bytes('<a><b></b>B2<c></c>C2</a>'))
        b, c = a

        del a[:]

        self.assertEqual("B2", b.tail)
        self.assertEqual("C2", c.tail)

    def test_delslice_memory(self):
        # this could trigger a crash
        Element = self.etree.Element
        SubElement = self.etree.SubElement
        a = Element('a')
        b = SubElement(a, 'b')
        c = SubElement(b, 'c')
        del b # no more reference to b
        del a[:]
        self.assertEqual('c', c.tag)

    def test_setslice(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        c = SubElement(a, 'c')
        d = SubElement(a, 'd')

        e = Element('e')
        f = Element('f')
        g = Element('g')

        s = [e, f, g]
        a[1:2] = s
        self.assertEqual(
            [b, e, f, g, d],
            list(a))

    def test_setslice_all(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        c = SubElement(a, 'c')

        e = Element('e')
        f = Element('f')
        g = Element('g')

        s = [e, f, g]
        a[:] = s
        self.assertEqual(
            [e, f, g],
            list(a))

    def test_setslice_all_empty(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')

        e = Element('e')
        f = Element('f')
        g = Element('g')

        s = [e, f, g]
        a[:] = s
        self.assertEqual(
            [e, f, g],
            list(a))

    def test_setslice_all_replace(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        c = SubElement(a, 'c')
        d = SubElement(a, 'd')

        s = [b, c, d]
        a[:] = s
        self.assertEqual(
            [b, c, d],
            list(a))

    def test_setslice_all_replace_reversed(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        c = SubElement(a, 'c')
        d = SubElement(a, 'd')

        s = [d, c, b]
        a[:] = s
        self.assertEqual(
            [d, c, b],
            list(a))

    def test_setslice_all_replace_reversed_ns1(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('{ns}a')
        b = SubElement(a, '{ns}b', {'{ns1}a1': 'test'})
        c = SubElement(a, '{ns}c', {'{ns2}a2': 'test'})
        d = SubElement(a, '{ns}d', {'{ns3}a3': 'test'})

        s = [d, c, b]
        a[:] = s
        self.assertEqual(
            [d, c, b],
            list(a))
        self.assertEqual(
            ['{ns}d', '{ns}c', '{ns}b'],
            [ child.tag for child in a ])

        self.assertEqual(
            [['{ns3}a3'], ['{ns2}a2'], ['{ns1}a1']],
            [ list(child.attrib.keys()) for child in a ])

    def test_setslice_all_replace_reversed_ns2(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('{ns}a')
        b = SubElement(a, '{ns1}b', {'{ns}a1': 'test'})
        c = SubElement(a, '{ns2}c', {'{ns}a2': 'test'})
        d = SubElement(a, '{ns3}d', {'{ns}a3': 'test'})

        s = [d, c, b]
        a[:] = s
        self.assertEqual(
            [d, c, b],
            list(a))
        self.assertEqual(
            ['{ns3}d', '{ns2}c', '{ns1}b'],
            [ child.tag for child in a ])

        self.assertEqual(
            [['{ns}a3'], ['{ns}a2'], ['{ns}a1']],
            [ list(child.attrib.keys()) for child in a ])

    def test_setslice_end(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        c = SubElement(a, 'c')

        e = Element('e')
        f = Element('f')
        g = Element('g')
        h = Element('h')

        s = [e, f]
        a[99:] = s
        self.assertEqual(
            [b, c, e, f],
            list(a))

        s = [g, h]
        a[:0] = s
        self.assertEqual(
            [g, h, b, c, e, f],
            list(a))

    def test_setslice_end_exact(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        c = SubElement(a, 'c')
        d = SubElement(a, 'd')

        e = Element('e')
        f = Element('f')
        g = Element('g')

        s = [e, f, g]
        a[3:] = s
        self.assertEqual(
            [b, c, d, e, f, g],
            list(a))

    def test_setslice_single(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        c = SubElement(a, 'c')

        e = Element('e')
        f = Element('f')

        s = [e]
        a[0:1] = s
        self.assertEqual(
            [e, c],
            list(a))

        s = [f]
        a[1:2] = s
        self.assertEqual(
            [e, f],
            list(a))

    def test_setslice_tail(self):
        ElementTree = self.etree.ElementTree
        Element = self.etree.Element
        f = BytesIO('<a><b></b>B2<c></c>C2<d></d>D2<e></e>E2</a>')
        doc = ElementTree(file=f)
        a = doc.getroot()
        x = Element('x')
        y = Element('y')
        z = Element('z')
        x.tail = 'X2'
        y.tail = 'Y2'
        z.tail = 'Z2'
        a[1:3] = [x, y, z]
        self.assertXML(
            _bytes('<a><b></b>B2<x></x>X2<y></y>Y2<z></z>Z2<e></e>E2</a>'),
            a)

    def test_setslice_negative(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        c = SubElement(a, 'c')
        d = SubElement(a, 'd')

        x = Element('x')
        y = Element('y')

        a[1:-1] = [x, y]
        self.assertEqual(
            [b, x, y, d],
            list(a))

    def test_setslice_negative2(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        c = SubElement(a, 'c')
        d = SubElement(a, 'd')

        x = Element('x')
        y = Element('y')

        a[1:-2] = [x, y]
        self.assertEqual(
            [b, x, y, c, d],
            list(a))

    def test_setslice_empty(self):
        Element = self.etree.Element

        a = Element('a')

        b = Element('b')
        c = Element('c')

        a[:] = [b, c]
        self.assertEqual(
            [b, c],
            list(a))

    def test_tail_elementtree_root(self):
        Element = self.etree.Element
        ElementTree = self.etree.ElementTree

        a = Element('a')
        a.tail = 'A2'
        t = ElementTree(element=a)
        self.assertEqual('A2',
                          a.tail)

    def test_ns_access(self):
        ElementTree = self.etree.ElementTree
        ns = 'http://xml.infrae.com/1'
        f = BytesIO('<x:a xmlns:x="%s"><x:b></x:b></x:a>' % ns)
        t = ElementTree(file=f)
        a = t.getroot()
        self.assertEqual('{%s}a' % ns,
                          a.tag)
        self.assertEqual('{%s}b' % ns,
                          a[0].tag)

    def test_ns_access2(self):
        ElementTree = self.etree.ElementTree
        ns = 'http://xml.infrae.com/1'
        ns2 = 'http://xml.infrae.com/2'
        f = BytesIO('<x:a xmlns:x="%s" xmlns:y="%s"><x:b></x:b><y:b></y:b></x:a>' % (ns, ns2))
        t = ElementTree(file=f)
        a = t.getroot()
        self.assertEqual('{%s}a' % ns,
                          a.tag)
        self.assertEqual('{%s}b' % ns,
                          a[0].tag)
        self.assertEqual('{%s}b' % ns2,
                          a[1].tag)

    def test_ns_setting(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement
        ns = 'http://xml.infrae.com/1'
        ns2 = 'http://xml.infrae.com/2'
        a = Element('{%s}a' % ns)
        b = SubElement(a, '{%s}b' % ns2)
        c = SubElement(a, '{%s}c' % ns)
        self.assertEqual('{%s}a' % ns,
                          a.tag)
        self.assertEqual('{%s}b' % ns2,
                          b.tag)
        self.assertEqual('{%s}c' % ns,
                          c.tag)
        self.assertEqual('{%s}a' % ns,
                          a.tag)
        self.assertEqual('{%s}b' % ns2,
                          b.tag)
        self.assertEqual('{%s}c' % ns,
                          c.tag)

    def test_ns_tag_parse(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement
        ElementTree = self.etree.ElementTree

        ns = 'http://xml.infrae.com/1'
        ns2 = 'http://xml.infrae.com/2'
        f = BytesIO('<a xmlns="%s" xmlns:x="%s"><x:b></x:b><b></b></a>' % (ns, ns2))
        t = ElementTree(file=f)

        a = t.getroot()
        self.assertEqual('{%s}a' % ns,
                          a.tag)
        self.assertEqual('{%s}b' % ns2,
                          a[0].tag)
        self.assertEqual('{%s}b' % ns,
                          a[1].tag)

    def test_ns_attr(self):
        Element = self.etree.Element
        ns = 'http://xml.infrae.com/1'
        ns2 = 'http://xml.infrae.com/2'
        a = Element('a')
        a.set('{%s}foo' % ns, 'Foo')
        a.set('{%s}bar' % ns2, 'Bar')
        self.assertEqual(
            'Foo',
            a.get('{%s}foo' % ns))
        self.assertEqual(
            'Bar',
            a.get('{%s}bar' % ns2))
        try:
            self.assertXML(
                _bytes('<a xmlns:ns0="%s" xmlns:ns1="%s" ns0:foo="Foo" ns1:bar="Bar"></a>' % (ns, ns2)),
                a)
        except AssertionError:
            self.assertXML(
                _bytes('<a xmlns:ns0="%s" xmlns:ns1="%s" ns1:foo="Foo" ns0:bar="Bar"></a>' % (ns2, ns)),
                a)

    def test_ns_move(self):
        Element = self.etree.Element
        one = self.etree.fromstring(
            _bytes('<foo><bar xmlns:ns="http://a.b.c"><ns:baz/></bar></foo>'))
        baz = one[0][0]

        two = Element('root')
        two.append(baz)
        # removing the originating document could cause a crash/error before
        # as namespace is not moved along with it
        del one, baz
        self.assertEqual('{http://a.b.c}baz', two[0].tag)

    def test_ns_decl_tostring(self):
        tostring = self.etree.tostring
        root = self.etree.XML(
            _bytes('<foo><bar xmlns:ns="http://a.b.c"><ns:baz/></bar></foo>'))
        baz = root[0][0]

        nsdecl = re.findall(_bytes("xmlns(?::[a-z0-9]+)?=[\"']([^\"']+)[\"']"),
                            tostring(baz))
        self.assertEqual([_bytes("http://a.b.c")], nsdecl)

    def test_ns_decl_tostring_default(self):
        tostring = self.etree.tostring
        root = self.etree.XML(
            _bytes('<foo><bar xmlns="http://a.b.c"><baz/></bar></foo>'))
        baz = root[0][0]

        nsdecl = re.findall(_bytes("xmlns(?::[a-z0-9]+)?=[\"']([^\"']+)[\"']"),
                            tostring(baz))
        self.assertEqual([_bytes("http://a.b.c")], nsdecl)

    def test_ns_decl_tostring_root(self):
        tostring = self.etree.tostring
        root = self.etree.XML(
            _bytes('<foo xmlns:ns="http://a.b.c"><bar><ns:baz/></bar></foo>'))
        baz = root[0][0]

        nsdecl = re.findall(_bytes("xmlns(?::[a-z0-9]+)?=[\"']([^\"']+)[\"']"),
                            tostring(baz))

        self.assertEqual([_bytes("http://a.b.c")], nsdecl)

    def test_ns_decl_tostring_element(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        root = Element("foo")
        bar = SubElement(root, "{http://a.b.c}bar")
        baz = SubElement(bar, "{http://a.b.c}baz")

        nsdecl = re.findall(_bytes("xmlns(?::[a-z0-9]+)?=[\"']([^\"']+)[\"']"),
                            self.etree.tostring(baz))

        self.assertEqual([_bytes("http://a.b.c")], nsdecl)

    def test_attribute_xmlns_move(self):
        Element = self.etree.Element

        root = Element('element')

        subelement = Element('subelement',
                             {"{http://www.w3.org/XML/1998/namespace}id": "foo"})
        self.assertEqual(1, len(subelement.attrib))
        self.assertEqual(
            "foo",
            subelement.get("{http://www.w3.org/XML/1998/namespace}id"))

        root.append(subelement)
        self.assertEqual(1, len(subelement.attrib))
        self.assertEqual(
            list({"{http://www.w3.org/XML/1998/namespace}id" : "foo"}.items()),
            list(subelement.attrib.items()))
        self.assertEqual(
            "foo",
            subelement.get("{http://www.w3.org/XML/1998/namespace}id"))

    def test_namespaces_after_serialize(self):
        parse = self.etree.parse
        tostring = self.etree.tostring

        ns_href = "http://a.b.c"
        one = parse(
            BytesIO('<foo><bar xmlns:ns="%s"><ns:baz/></bar></foo>' % ns_href))
        baz = one.getroot()[0][0]

        parsed = parse(BytesIO( tostring(baz) )).getroot()
        self.assertEqual('{%s}baz' % ns_href, parsed.tag)

    def test_attribute_namespace_roundtrip(self):
        fromstring = self.etree.fromstring
        tostring = self.etree.tostring

        ns_href = "http://a.b.c"
        xml = _bytes('<root xmlns="%s" xmlns:x="%s"><el x:a="test" /></root>' % (
                ns_href,ns_href))
        root = fromstring(xml)
        self.assertEqual('test', root[0].get('{%s}a' % ns_href))

        xml2 = tostring(root)
        self.assertTrue(_bytes(':a=') in xml2, xml2)

        root2 = fromstring(xml2)
        self.assertEqual('test', root2[0].get('{%s}a' % ns_href))

    def test_attribute_namespace_roundtrip_replaced(self):
        fromstring = self.etree.fromstring
        tostring = self.etree.tostring

        ns_href = "http://a.b.c"
        xml = _bytes('<root xmlns="%s" xmlns:x="%s"><el x:a="test" /></root>' % (
                ns_href,ns_href))
        root = fromstring(xml)
        self.assertEqual('test', root[0].get('{%s}a' % ns_href))

        root[0].set('{%s}a' % ns_href, 'TEST')

        xml2 = tostring(root)
        self.assertTrue(_bytes(':a=') in xml2, xml2)

        root2 = fromstring(xml2)
        self.assertEqual('TEST', root2[0].get('{%s}a' % ns_href))

    required_versions_ET['test_register_namespace'] = (1,3)
    def test_register_namespace(self):
        # ET 1.3+
        Element = self.etree.Element
        prefix = 'TESTPREFIX'
        namespace = 'http://seriously.unknown/namespace/URI'

        el = Element('{%s}test' % namespace)
        self.assertEqual(_bytes('<ns0:test xmlns:ns0="%s"></ns0:test>' % namespace),
            self._writeElement(el))

        self.etree.register_namespace(prefix, namespace)
        el = Element('{%s}test' % namespace)
        self.assertEqual(_bytes('<%s:test xmlns:%s="%s"></%s:test>' % (
            prefix, prefix, namespace, prefix)),
            self._writeElement(el))

        self.assertRaises(ValueError, self.etree.register_namespace, 'ns25', namespace)

    def test_tostring(self):
        tostring = self.etree.tostring
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        c = SubElement(a, 'c')

        self.assertEqual(_bytes('<a><b></b><c></c></a>'),
                          canonicalize(tostring(a)))

    def test_tostring_element(self):
        tostring = self.etree.tostring
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        c = SubElement(a, 'c')
        d = SubElement(c, 'd')
        self.assertEqual(_bytes('<b></b>'),
                          canonicalize(tostring(b)))
        self.assertEqual(_bytes('<c><d></d></c>'),
                          canonicalize(tostring(c)))

    def test_tostring_element_tail(self):
        tostring = self.etree.tostring
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        b = SubElement(a, 'b')
        c = SubElement(a, 'c')
        d = SubElement(c, 'd')
        b.tail = 'Foo'

        self.assertTrue(tostring(b) == _bytes('<b/>Foo') or
                     tostring(b) == _bytes('<b />Foo'))

    required_versions_ET['test_tostring_method_html'] = (1,3)
    def test_tostring_method_html(self):
        tostring = self.etree.tostring
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        html = Element('html')
        body = SubElement(html, 'body')
        p = SubElement(body, 'p')
        p.text = "html"
        SubElement(p, 'br').tail = "test"

        self.assertEqual(_bytes('<html><body><p>html<br>test</p></body></html>'),
                          tostring(html, method="html"))

    required_versions_ET['test_tostring_method_text'] = (1,3)
    def test_tostring_method_text(self):
        tostring = self.etree.tostring
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        a = Element('a')
        a.text = "A"
        a.tail = "tail"
        b = SubElement(a, 'b')
        b.text = "B"
        b.tail = "TAIL"
        c = SubElement(a, 'c')
        c.text = "C"

        self.assertEqual(_bytes('ABTAILCtail'),
                          tostring(a, method="text"))

    def test_iterparse(self):
        iterparse = self.etree.iterparse
        f = BytesIO('<a><b></b><c/></a>')

        iterator = iterparse(f)
        self.assertEqual(None,
                          iterator.root)
        events = list(iterator)
        root = iterator.root
        self.assertEqual(
            [('end', root[0]), ('end', root[1]), ('end', root)],
            events)

    def test_iterparse_incomplete(self):
        iterparse = self.etree.iterparse
        f = BytesIO('<a><b></b><c/></a>')

        iterator = iterparse(f)
        self.assertEqual(None,
                          iterator.root)
        event, element = next(iter(iterator))
        self.assertEqual('end', event)
        self.assertEqual('b', element.tag)

    def test_iterparse_file(self):
        iterparse = self.etree.iterparse
        iterator = iterparse(fileInTestDir("test.xml"))
        self.assertEqual(None,
                          iterator.root)
        events = list(iterator)
        root = iterator.root
        self.assertEqual(
            [('end', root[0]), ('end', root)],
            events)

    def test_iterparse_start(self):
        iterparse = self.etree.iterparse
        f = BytesIO('<a><b></b><c/></a>')

        iterator = iterparse(f, events=('start',))
        events = list(iterator)
        root = iterator.root
        self.assertEqual(
            [('start', root), ('start', root[0]), ('start', root[1])],
            events)

    def test_iterparse_start_end(self):
        iterparse = self.etree.iterparse
        f = BytesIO('<a><b></b><c/></a>')

        iterator = iterparse(f, events=('start','end'))
        events = list(iterator)
        root = iterator.root
        self.assertEqual(
            [('start', root), ('start', root[0]), ('end', root[0]),
             ('start', root[1]), ('end', root[1]), ('end', root)],
            events)

    def test_iterparse_clear(self):
        iterparse = self.etree.iterparse
        f = BytesIO('<a><b></b><c/></a>')

        iterator = iterparse(f)
        for event, elem in iterator:
            elem.clear()

        root = iterator.root
        self.assertEqual(0,
                          len(root))

    def test_iterparse_large(self):
        iterparse = self.etree.iterparse
        CHILD_COUNT = 12345
        f = BytesIO('<a>%s</a>' % ('<b>test</b>'*CHILD_COUNT))

        i = 0
        for key in iterparse(f):
            event, element = key
            i += 1
        self.assertEqual(i, CHILD_COUNT + 1)

    def test_iterparse_set_ns_attribute(self):
        iterparse = self.etree.iterparse
        f = BytesIO('<a xmlns="http://ns1/"><b><c xmlns="http://ns2/"/></b></a>')

        attr_name = '{http://testns/}bla'
        events = []
        iterator = iterparse(f, events=('start','end','start-ns','end-ns'))
        for event, elem in iterator:
            events.append(event)
            if event == 'start':
                if elem.tag != '{http://ns1/}a':
                    elem.set(attr_name, 'value')

        self.assertEqual(
            ['start-ns', 'start', 'start', 'start-ns', 'start',
             'end', 'end-ns', 'end', 'end', 'end-ns'],
            events)

        root = iterator.root
        self.assertEqual(
            None,
            root.get(attr_name))
        self.assertEqual(
            'value',
            root[0].get(attr_name))

    def test_iterparse_only_end_ns(self):
        iterparse = self.etree.iterparse
        f = BytesIO('<a xmlns="http://ns1/"><b><c xmlns="http://ns2/"/></b></a>')

        attr_name = '{http://testns/}bla'
        events = []
        iterator = iterparse(f, events=('start','end','start-ns','end-ns'))
        for event, elem in iterator:
            events.append(event)
            if event == 'start':
                if elem.tag != '{http://ns1/}a':
                    elem.set(attr_name, 'value')

        self.assertEqual(
            ['start-ns', 'start', 'start', 'start-ns', 'start',
             'end', 'end-ns', 'end', 'end', 'end-ns'],
            events)

        root = iterator.root
        self.assertEqual(
            None,
            root.get(attr_name))
        self.assertEqual(
            'value',
            root[0].get(attr_name))

    def test_iterparse_move_elements(self):
        iterparse = self.etree.iterparse
        f = BytesIO('<a><b><d/></b><c/></a>')

        for event, node in etree.iterparse(f): pass

        root = etree.Element('new_root', {})
        root[:] = node[:]

        self.assertEqual(
            ['b', 'c'],
            [ el.tag for el in root ])

    def test_iterparse_cdata(self):
        tostring = self.etree.tostring
        f = BytesIO('<root><![CDATA[test]]></root>')
        context = self.etree.iterparse(f)
        content = [ el.text for event,el in context ]

        self.assertEqual(['test'], content)
        self.assertEqual(_bytes('<root>test</root>'),
                          tostring(context.root))

    def test_parse_file(self):
        parse = self.etree.parse
        # from file
        tree = parse(fileInTestDir('test.xml'))
        self.assertXML(
            _bytes('<a><b></b></a>'),
            tree.getroot())

    def test_parse_file_nonexistent(self):
        parse = self.etree.parse
        self.assertRaises(IOError, parse, fileInTestDir('notthere.xml'))  

    def test_parse_error_none(self):
        parse = self.etree.parse
        self.assertRaises(TypeError, parse, None)

    required_versions_ET['test_parse_error'] = (1,3)
    def test_parse_error(self):
        # ET < 1.3 raises ExpatError
        parse = self.etree.parse
        f = BytesIO('<a><b></c></b></a>')
        self.assertRaises(SyntaxError, parse, f)
        f.close()

    required_versions_ET['test_parse_error_from_file'] = (1,3)
    def test_parse_error_from_file(self):
        parse = self.etree.parse
        # from file
        f = open(fileInTestDir('test_broken.xml'), 'rb')
        self.assertRaises(SyntaxError, parse, f)
        f.close()

    def test_parse_file_object(self):
        parse = self.etree.parse
        # from file object
        f = open(fileInTestDir('test.xml'), 'rb')
        tree = parse(f)
        f.close()
        self.assertXML(
            _bytes('<a><b></b></a>'),
            tree.getroot())

    def test_parse_stringio(self):
        parse = self.etree.parse
        f = BytesIO('<a><b></b></a>')
        tree = parse(f)
        f.close()
        self.assertXML(
            _bytes('<a><b></b></a>'),
            tree.getroot()
           )

    def test_parse_cdata(self):
        tostring = self.etree.tostring
        root = self.etree.XML(_bytes('<root><![CDATA[test]]></root>'))

        self.assertEqual('test', root.text)
        self.assertEqual(_bytes('<root>test</root>'),
                          tostring(root))

    def test_parse_with_encoding(self):
        # this can fail in libxml2 <= 2.6.22
        parse = self.etree.parse
        tree = parse(BytesIO('<?xml version="1.0" encoding="ascii"?><html/>'))
        self.assertXML(_bytes('<html></html>'),
                       tree.getroot())

    def test_encoding(self):
        Element = self.etree.Element

        a = Element('a')
        a.text = _str('Søk på nettet')
        self.assertXML(
            _str('<a>Søk på nettet</a>').encode('UTF-8'),
            a, 'utf-8')

    def test_encoding_exact(self):
        ElementTree = self.etree.ElementTree
        Element = self.etree.Element

        a = Element('a')
        a.text = _str('Søk på nettet')

        f = BytesIO()
        tree = ElementTree(element=a)
        tree.write(f, encoding='utf-8')
        self.assertEqual(_str('<a>Søk på nettet</a>').encode('UTF-8'),
                          f.getvalue().replace(_bytes('\n'),_bytes('')))

    def test_parse_file_encoding(self):
        parse = self.etree.parse
        # from file
        tree = parse(fileInTestDir('test-string.xml'))
        self.assertXML(
            _str('<a>Søk på nettet</a>').encode('UTF-8'),
            tree.getroot(), 'UTF-8')

    def test_parse_file_object_encoding(self):
        parse = self.etree.parse
        # from file object
        f = open(fileInTestDir('test-string.xml'), 'rb')
        tree = parse(f)
        f.close()
        self.assertXML(
            _str('<a>Søk på nettet</a>').encode('UTF-8'),
            tree.getroot(), 'UTF-8')

    def test_encoding_8bit_latin1(self):
        ElementTree = self.etree.ElementTree
        Element = self.etree.Element

        a = Element('a')
        a.text = _str('Søk på nettet')

        f = BytesIO()
        tree = ElementTree(element=a)
        tree.write(f, encoding='iso-8859-1')
        result = f.getvalue()
        declaration = _bytes("<?xml version=\'1.0\' encoding=\'iso-8859-1\'?>")
        self.assertEncodingDeclaration(result, _bytes('iso-8859-1'))
        result = result.split(_bytes('?>'), 1)[-1].replace(_bytes('\n'),_bytes(''))
        self.assertEqual(_str('<a>Søk på nettet</a>').encode('iso-8859-1'),
                          result)

    required_versions_ET['test_parse_encoding_8bit_explicit'] = (1,3)
    def test_parse_encoding_8bit_explicit(self):
        XMLParser = self.XMLParser

        text = _str('Søk på nettet')
        xml_latin1 = (_str('<a>%s</a>') % text).encode('iso-8859-1')

        self.assertRaises(self.etree.ParseError,
                          self.etree.parse,
                          BytesIO(xml_latin1))

        tree = self.etree.parse(BytesIO(xml_latin1),
                                XMLParser(encoding="iso-8859-1"))
        a = tree.getroot()
        self.assertEqual(a.text, text)

    required_versions_ET['test_parse_encoding_8bit_override'] = (1,3)
    def test_parse_encoding_8bit_override(self):
        XMLParser = self.XMLParser

        text = _str('Søk på nettet')
        wrong_declaration = _str("<?xml version='1.0' encoding='UTF-8'?>")
        xml_latin1 = (_str('%s<a>%s</a>') % (wrong_declaration, text)
                      ).encode('iso-8859-1')

        self.assertRaises(self.etree.ParseError,
                          self.etree.parse,
                          BytesIO(xml_latin1))

        tree = self.etree.parse(BytesIO(xml_latin1),
                                XMLParser(encoding="iso-8859-1"))
        a = tree.getroot()
        self.assertEqual(a.text, text)

    def _test_wrong_unicode_encoding(self):
        # raise error on wrong encoding declaration in unicode strings
        XML = self.etree.XML
        test_utf = (_str('<?xml version="1.0" encoding="iso-8859-1"?>') +
                    _str('<a>Søk på nettet</a>'))
        self.assertRaises(SyntaxError, XML, test_utf)

    def test_encoding_write_default_encoding(self):
        ElementTree = self.etree.ElementTree
        Element = self.etree.Element

        a = Element('a')
        a.text = _str('Søk på nettet')

        f = BytesIO()
        tree = ElementTree(element=a)
        tree.write(f)
        data = f.getvalue().replace(_bytes('\n'),_bytes(''))
        self.assertEqual(
            _str('<a>Søk på nettet</a>').encode('ASCII', 'xmlcharrefreplace'),
            data)

    def test_encoding_tostring(self):
        Element = self.etree.Element
        tostring = self.etree.tostring

        a = Element('a')
        a.text = _str('Søk på nettet')
        self.assertEqual(_str('<a>Søk på nettet</a>').encode('UTF-8'),
                         tostring(a, encoding='utf-8'))

    def test_encoding_tostring_unknown(self):
        Element = self.etree.Element
        tostring = self.etree.tostring

        a = Element('a')
        a.text = _str('Søk på nettet')
        self.assertRaises(LookupError, tostring, a,
                          encoding='Invalid Encoding')

    def test_encoding_tostring_sub(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement
        tostring = self.etree.tostring

        a = Element('a')
        b = SubElement(a, 'b')
        b.text = _str('Søk på nettet')
        self.assertEqual(_str('<b>Søk på nettet</b>').encode('UTF-8'),
                         tostring(b, encoding='utf-8'))

    def test_encoding_tostring_sub_tail(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement
        tostring = self.etree.tostring

        a = Element('a')
        b = SubElement(a, 'b')
        b.text = _str('Søk på nettet')
        b.tail = _str('Søk')
        self.assertEqual(_str('<b>Søk på nettet</b>Søk').encode('UTF-8'),
                         tostring(b, encoding='utf-8'))

    def test_encoding_tostring_default_encoding(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement
        tostring = self.etree.tostring

        a = Element('a')
        a.text = _str('Søk på nettet')

        expected = _bytes('<a>S&#248;k p&#229; nettet</a>')
        self.assertEqual(
            expected,
            tostring(a))

    def test_encoding_sub_tostring_default_encoding(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement
        tostring = self.etree.tostring

        a = Element('a')
        b = SubElement(a, 'b')
        b.text = _str('Søk på nettet')

        expected = _bytes('<b>S&#248;k p&#229; nettet</b>')
        self.assertEqual(
            expected,
            tostring(b))

    def test_encoding_8bit_xml(self):
        utext = _str('Søk på nettet')
        uxml = _str('<p>%s</p>') % utext
        prologue = _bytes('<?xml version="1.0" encoding="iso-8859-1" ?>')
        isoxml = prologue + uxml.encode('iso-8859-1')
        tree = self.etree.XML(isoxml)
        self.assertEqual(utext, tree.text)

    def test_encoding_utf8_bom(self):
        utext = _str('Søk på nettet')
        uxml = (_str('<?xml version="1.0" encoding="UTF-8"?>') +
                _str('<p>%s</p>') % utext)
        bom = _bytes('\\xEF\\xBB\\xBF').decode("unicode_escape").encode("latin1")
        xml = bom + uxml.encode("utf-8")
        tree = etree.XML(xml)
        self.assertEqual(utext, tree.text)

    def test_encoding_8bit_parse_stringio(self):
        utext = _str('Søk på nettet')
        uxml = _str('<p>%s</p>') % utext
        prologue = _bytes('<?xml version="1.0" encoding="iso-8859-1" ?>')
        isoxml = prologue + uxml.encode('iso-8859-1')
        el = self.etree.parse(BytesIO(isoxml)).getroot()
        self.assertEqual(utext, el.text)

    def test_deepcopy_elementtree(self):
        Element = self.etree.Element
        ElementTree = self.etree.ElementTree

        a = Element('a')
        a.text = "Foo"
        atree = ElementTree(a)

        btree = copy.deepcopy(atree)
        self.assertEqual("Foo", atree.getroot().text)
        self.assertEqual("Foo", btree.getroot().text)
        self.assertFalse(btree is atree)
        self.assertFalse(btree.getroot() is atree.getroot())

    def test_deepcopy(self):
        Element = self.etree.Element

        a = Element('a')
        a.text = 'Foo'

        b = copy.deepcopy(a)
        self.assertEqual('Foo', b.text)

        b.text = 'Bar'
        self.assertEqual('Bar', b.text)
        self.assertEqual('Foo', a.text)

        del a
        self.assertEqual('Bar', b.text)

    def test_deepcopy_tail(self):
        Element = self.etree.Element

        a = Element('a')
        a.tail = 'Foo'

        b = copy.deepcopy(a)
        self.assertEqual('Foo', b.tail)

        b.tail = 'Bar'
        self.assertEqual('Bar', b.tail)
        self.assertEqual('Foo', a.tail)

        del a
        self.assertEqual('Bar', b.tail)

    def test_deepcopy_subelement(self):
        Element = self.etree.Element
        SubElement = self.etree.SubElement

        root = Element('root')
        a = SubElement(root, 'a')
        a.text = 'FooText'
        a.tail = 'FooTail'

        b = copy.deepcopy(a)
        self.assertEqual('FooText', b.text)
        self.assertEqual('FooTail', b.tail)

        b.text = 'BarText'
        b.tail = 'BarTail'
        self.assertEqual('BarTail', b.tail)
        self.assertEqual('FooTail', a.tail)
        self.assertEqual('BarText', b.text)
        self.assertEqual('FooText', a.text)

        del a
        self.assertEqual('BarTail', b.tail)
        self.assertEqual('BarText', b.text)

    def test_deepcopy_namespaces(self):
        root = self.etree.XML(_bytes('''<doc xmlns="dns" xmlns:t="tns">
        <parent><node t:foo="bar" /></parent>
        </doc>'''))
        self.assertEqual(
            root[0][0].get('{tns}foo'),
            copy.deepcopy(root[0])[0].get('{tns}foo') )
        self.assertEqual(
            root[0][0].get('{tns}foo'),
            copy.deepcopy(root[0][0]).get('{tns}foo') )

    def test_deepcopy_append(self):
        # previously caused a crash
        Element = self.etree.Element
        tostring = self.etree.tostring

        a = Element('a')
        b = copy.deepcopy(a)
        a.append( Element('C') )
        b.append( Element('X') )

        self.assertEqual(_bytes('<a><C/></a>'),
                          tostring(a).replace(_bytes(' '), _bytes('')))
        self.assertEqual(_bytes('<a><X/></a>'),
                          tostring(b).replace(_bytes(' '), _bytes('')))

    def test_deepcopy_comment(self):
        # previously caused a crash
        # not supported by ET < 1.3!
        Comment = self.etree.Comment

        a = Comment("ONE")
        b = copy.deepcopy(a)
        b.text = "ANOTHER"

        self.assertEqual('ONE',     a.text)
        self.assertEqual('ANOTHER', b.text)

    def test_shallowcopy(self):
        Element = self.etree.Element

        a = Element('a')
        a.text = 'Foo'

        b = copy.copy(a)
        self.assertEqual('Foo', b.text)

        b.text = 'Bar'
        self.assertEqual('Bar', b.text)
        self.assertEqual('Foo', a.text)
        # XXX ElementTree will share nodes, but lxml.etree won't..

    def test_shallowcopy_elementtree(self):
        Element = self.etree.Element
        ElementTree = self.etree.ElementTree

        a = Element('a')
        a.text = 'Foo'
        atree = ElementTree(a)

        btree = copy.copy(atree)
        self.assertFalse(btree is atree)
        self.assertTrue(btree.getroot() is atree.getroot())
        self.assertEqual('Foo', atree.getroot().text)

    def _test_element_boolean(self):
        # deprecated as of ET 1.3/lxml 2.0
        etree = self.etree
        e = etree.Element('foo')
        self.assertEqual(False, bool(e))
        etree.SubElement(e, 'bar')
        self.assertEqual(True, bool(e))
        e = etree.Element('foo')
        e.text = 'hey'
        self.assertEqual(False, bool(e))
        e = etree.Element('foo')
        e.tail = 'bar'
        self.assertEqual(False, bool(e))
        e = etree.Element('foo')
        e.set('bar', 'Bar')
        self.assertEqual(False, bool(e))

    def test_multiple_elementrees(self):
        etree = self.etree

        a = etree.Element('a')
        b = etree.SubElement(a, 'b')

        t = etree.ElementTree(a)
        self.assertEqual(self._rootstring(t), _bytes('<a><b/></a>'))

        t1 = etree.ElementTree(a)
        self.assertEqual(self._rootstring(t1), _bytes('<a><b/></a>'))
        self.assertEqual(self._rootstring(t),  _bytes('<a><b/></a>'))

        t2 = etree.ElementTree(b)
        self.assertEqual(self._rootstring(t2), _bytes('<b/>'))
        self.assertEqual(self._rootstring(t1), _bytes('<a><b/></a>'))
        self.assertEqual(self._rootstring(t),  _bytes('<a><b/></a>'))

    def test_qname(self):
        etree = self.etree
        qname = etree.QName('myns', 'a')
        a1 = etree.Element(qname)
        a2 = etree.SubElement(a1, qname)
        self.assertEqual(a1.tag, "{myns}a")
        self.assertEqual(a2.tag, "{myns}a")

    def test_qname_cmp(self):
        etree = self.etree
        qname1 = etree.QName('myns', 'a')
        qname2 = etree.QName('myns', 'a')
        self.assertEqual(qname1, "{myns}a")
        self.assertEqual("{myns}a", qname2)
        self.assertEqual(qname1, qname1)
        self.assertEqual(qname1, qname2)

    def test_qname_attribute_getset(self):
        etree = self.etree
        qname = etree.QName('myns', 'a')

        a = etree.Element(qname)
        a.set(qname, "value")

        self.assertEqual(a.get(qname), "value")
        self.assertEqual(a.get("{myns}a"), "value")

    def test_qname_attrib(self):
        etree = self.etree
        qname = etree.QName('myns', 'a')

        a = etree.Element(qname)
        a.attrib[qname] = "value"

        self.assertEqual(a.attrib[qname], "value")
        self.assertEqual(a.attrib.get(qname), "value")

        self.assertEqual(a.attrib["{myns}a"], "value")
        self.assertEqual(a.attrib.get("{myns}a"), "value")

    def test_qname_attribute_resolve(self):
        etree = self.etree
        qname = etree.QName('http://myns', 'a')
        a = etree.Element(qname)
        a.set(qname, qname)

        self.assertXML(
            _bytes('<ns0:a xmlns:ns0="http://myns" ns0:a="ns0:a"></ns0:a>'),
            a)

    def test_qname_attribute_resolve_new(self):
        etree = self.etree
        qname = etree.QName('http://myns', 'a')
        a = etree.Element('a')
        a.set('a', qname)

        self.assertXML(
            _bytes('<a xmlns:ns0="http://myns" a="ns0:a"></a>'),
            a)

    def test_qname_attrib_resolve(self):
        etree = self.etree
        qname = etree.QName('http://myns', 'a')
        a = etree.Element(qname)
        a.attrib[qname] = qname

        self.assertXML(
            _bytes('<ns0:a xmlns:ns0="http://myns" ns0:a="ns0:a"></ns0:a>'),
            a)

    def test_parser_version(self):
        etree = self.etree
        parser = etree.XMLParser()
        if hasattr(parser, "version"):
            # ElementTree 1.3+, cET
            self.assertTrue(re.match("[^ ]+ [0-9.]+", parser.version))

    # feed parser interface

    def test_feed_parser_bytes(self):
        parser = self.XMLParser()

        parser.feed(_bytes('<?xml version='))
        parser.feed(_bytes('"1.0"?><ro'))
        parser.feed(_bytes('ot><'))
        parser.feed(_bytes('a test="works"/'))
        parser.feed(_bytes('></root'))
        parser.feed(_bytes('>'))

        root = parser.close()

        self.assertEqual(root.tag, "root")
        self.assertEqual(root[0].tag, "a")
        self.assertEqual(root[0].get("test"), "works")

    def test_feed_parser_unicode_ascii(self):
        parser = self.XMLParser()

        parser.feed(_bytes(u'<?xml version='))
        parser.feed(_bytes(u'"1.0"?><ro'))
        parser.feed(_bytes(u'ot><'))
        parser.feed(_bytes(u'a test="works"/'))
        parser.feed(_bytes(u'></root'))
        parser.feed(_bytes(u'>'))

        root = parser.close()

        self.assertEqual(root.tag, "root")
        self.assertEqual(root[0].tag, "a")
        self.assertEqual(root[0].get("test"), "works")

    @et_needs_pyversion(3)
    def test_feed_parser_unicode_astral(self):
        parser = self.XMLParser()

        astral_chunk = u'-- \U00010143 --'  # astral (4 bytes/chr)
        latin1_chunk = u'-- \xf8 --'  # Latin1 (1 byte/chr)

        parser.feed(u'<ro')  # ASCII (1 byte/chr)
        parser.feed(u'ot><')
        parser.feed(u'a test="w\N{DIAMETER SIGN}rks">')  # BMP (2 bytes/chr)
        parser.feed(astral_chunk)
        parser.feed(latin1_chunk)
        parser.feed(u'</a></root')
        parser.feed(u'>')

        root = parser.close()

        self.assertEqual(root.tag, "root")
        self.assertEqual(root[0].tag, "a")
        self.assertEqual(root[0].get("test"), u"w\N{DIAMETER SIGN}rks")
        self.assertEqual(root[0].text, astral_chunk + latin1_chunk)

    @et_needs_pyversion(3)
    def test_feed_parser_unicode_astral_large(self):
        parser = self.XMLParser()

        astral_chunk = u'-- \U00010143 --' * (2 ** 16)  # astral (4 bytes/chr)
        latin1_chunk = u'-- \xf8 --'  # Latin1 (1 byte/chr)

        parser.feed(u'<ro')
        parser.feed(u'ot><')  # ASCII (1 byte/chr)
        parser.feed(u'a test="w\N{DIAMETER SIGN}rks">')  # BMP (2 bytes/chr)
        parser.feed(astral_chunk)
        parser.feed((astral_chunk + u"</a> <a>" + astral_chunk) * 16)
        parser.feed(latin1_chunk)
        parser.feed(u'</a></root')
        parser.feed(u'>')

        root = parser.close()

        self.assertEqual(root.tag, "root")
        self.assertEqual(root[0].get("test"), u"w\N{DIAMETER SIGN}rks")
        for child in root[:-1]:
            self.assertEqual(child.tag, "a")
            self.assertEqual(child.text, astral_chunk * 2)
        self.assertEqual(root[-1].tag, "a")
        self.assertEqual(root[-1].text, astral_chunk + latin1_chunk)

    required_versions_ET['test_feed_parser_error_close_empty'] = (1,3)
    def test_feed_parser_error_close_empty(self):
        ParseError = self.etree.ParseError
        parser = self.XMLParser()
        self.assertRaises(ParseError, parser.close)

    required_versions_ET['test_feed_parser_error_close_incomplete'] = (1,3)
    def test_feed_parser_error_close_incomplete(self):
        ParseError = self.etree.ParseError
        parser = self.XMLParser()

        parser.feed('<?xml version=')
        parser.feed('"1.0"?><ro')

        self.assertRaises(ParseError, parser.close)

    required_versions_ET['test_feed_parser_error_broken'] = (1,3)
    def test_feed_parser_error_broken(self):
        ParseError = self.etree.ParseError
        parser = self.XMLParser()

        parser.feed('<?xml version=')
        parser.feed('"1.0"?><ro')
        try:
            parser.feed('<><><><><><><')
        except ParseError:
            # can raise, but not required before close()
            pass

        self.assertRaises(ParseError, parser.close)

    required_versions_ET['test_feed_parser_error_position'] = (1,3)
    def test_feed_parser_error_position(self):
        ParseError = self.etree.ParseError
        parser = self.XMLParser()
        try:
            parser.close()
        except ParseError:
            e = sys.exc_info()[1]
            self.assertNotEqual(None, e.code)
            self.assertNotEqual(0, e.code)
            self.assertTrue(isinstance(e.position, tuple))
            self.assertTrue(e.position >= (0, 0))

    # parser target interface

    required_versions_ET['test_parser_target_property'] = (1,3)
    def test_parser_target_property(self):
        class Target(object):
            pass

        target = Target()
        parser = self.XMLParser(target=target)

        self.assertEqual(target, parser.target)

    def test_parser_target_tag(self):
        assertEqual = self.assertEqual
        assertFalse  = self.assertFalse

        events = []
        class Target(object):
            def start(self, tag, attrib):
                events.append("start")
                assertFalse(attrib)
                assertEqual("TAG", tag)
            def end(self, tag):
                events.append("end")
                assertEqual("TAG", tag)
            def close(self):
                return "DONE"

        parser = self.XMLParser(target=Target())

        parser.feed("<TAG/>")
        done = parser.close()

        self.assertEqual("DONE", done)
        self.assertEqual(["start", "end"], events)

    def test_parser_target_error_in_start(self):
        assertEqual = self.assertEqual

        events = []
        class Target(object):
            def start(self, tag, attrib):
                events.append("start")
                assertEqual("TAG", tag)
                raise ValueError("TEST")
            def end(self, tag):
                events.append("end")
                assertEqual("TAG", tag)
            def close(self):
                return "DONE"

        parser = self.XMLParser(target=Target())

        try:
            parser.feed("<TAG/>")
        except ValueError:
            self.assertTrue('TEST' in str(sys.exc_info()[1]))
        else:
            self.assertTrue(False)
        if 'lxml' in self.etree.__name__:
            self.assertEqual(["start"], events)
        else:
            # cElementTree calls end() as well
            self.assertTrue("start" in events)

    def test_parser_target_error_in_end(self):
        assertEqual = self.assertEqual

        events = []
        class Target(object):
            def start(self, tag, attrib):
                events.append("start")
                assertEqual("TAG", tag)
            def end(self, tag):
                events.append("end")
                assertEqual("TAG", tag)
                raise ValueError("TEST")
            def close(self):
                return "DONE"

        parser = self.XMLParser(target=Target())

        try:
            parser.feed("<TAG/>")
        except ValueError:
            self.assertTrue('TEST' in str(sys.exc_info()[1]))
        else:
            self.assertTrue(False)
        self.assertEqual(["start", "end"], events)

    def test_parser_target_error_in_close(self):
        assertEqual = self.assertEqual

        events = []
        class Target(object):
            def start(self, tag, attrib):
                events.append("start")
                assertEqual("TAG", tag)
            def end(self, tag):
                events.append("end")
                assertEqual("TAG", tag)
            def close(self):
                raise ValueError("TEST")

        parser = self.XMLParser(target=Target())

        try:
            parser.feed("<TAG/>")
            parser.close()
        except ValueError:
            self.assertTrue('TEST' in str(sys.exc_info()[1]))
        else:
            self.assertTrue(False)
        self.assertEqual(["start", "end"], events)

    def test_parser_target_error_in_start_and_close(self):
        assertEqual = self.assertEqual

        events = []
        class Target(object):
            def start(self, tag, attrib):
                events.append("start")
                assertEqual("TAG", tag)
                raise IndexError("TEST-IE")
            def end(self, tag):
                events.append("end")
                assertEqual("TAG", tag)
            def close(self):
                raise ValueError("TEST-VE")

        parser = self.XMLParser(target=Target())

        try:
            parser.feed("<TAG/>")
            parser.close()
        except IndexError:
            if 'lxml' in self.etree.__name__:
                # we try not to swallow the initial exception in Py2
                self.assertTrue(sys.version_info[0] < 3)
            self.assertTrue('TEST-IE' in str(sys.exc_info()[1]))
        except ValueError:
            if 'lxml' in self.etree.__name__:
                self.assertTrue(sys.version_info[0] >= 3)
            self.assertTrue('TEST-VE' in str(sys.exc_info()[1]))
        else:
            self.assertTrue(False)

        if 'lxml' in self.etree.__name__:
            self.assertEqual(["start"], events)
        else:
            # cElementTree calls end() as well
            self.assertTrue("start" in events)

    def test_elementtree_parser_target(self):
        assertEqual = self.assertEqual
        assertFalse  = self.assertFalse
        Element = self.etree.Element

        events = []
        class Target(object):
            def start(self, tag, attrib):
                events.append("start")
                assertFalse(attrib)
                assertEqual("TAG", tag)
            def end(self, tag):
                events.append("end")
                assertEqual("TAG", tag)
            def close(self):
                return Element("DONE")

        parser = self.XMLParser(target=Target())
        tree = self.etree.ElementTree()
        tree.parse(BytesIO("<TAG/>"), parser=parser)

        self.assertEqual("DONE", tree.getroot().tag)
        self.assertEqual(["start", "end"], events)

    def test_parser_target_attrib(self):
        assertEqual = self.assertEqual

        events = []
        class Target(object):
            def start(self, tag, attrib):
                events.append("start-" + tag)
                for name, value in attrib.items():
                    assertEqual(tag + name, value)
            def end(self, tag):
                events.append("end-" + tag)
            def close(self):
                return "DONE"

        parser = self.XMLParser(target=Target())

        parser.feed('<root a="roota" b="rootb"><sub c="subc"/></root>')
        done = parser.close()

        self.assertEqual("DONE", done)
        self.assertEqual(["start-root", "start-sub", "end-sub", "end-root"],
                          events)

    def test_parser_target_data(self):
        events = []
        class Target(object):
            def start(self, tag, attrib):
                events.append("start-" + tag)
            def end(self, tag):
                events.append("end-" + tag)
            def data(self, data):
                events.append("data-" + data)
            def close(self):
                return "DONE"

        parser = self.XMLParser(target=Target())

        parser.feed('<root>A<sub/>B</root>')
        done = parser.close()

        self.assertEqual("DONE", done)
        self.assertEqual(["start-root", "data-A", "start-sub",
                           "end-sub", "data-B", "end-root"],
                          events)

    def test_parser_target_entity(self):
        events = []
        class Target(object):
            def __init__(self):
                self._data = []
            def _flush_data(self):
                if self._data:
                    events.append("data-" + ''.join(self._data))
                    del self._data[:]
            def start(self, tag, attrib):
                self._flush_data()
                events.append("start-" + tag)
            def end(self, tag):
                self._flush_data()
                events.append("end-" + tag)
            def data(self, data):
                self._data.append(data)
            def close(self):
                self._flush_data()
                return "DONE"

        parser = self.XMLParser(target=Target())

        dtd = '''
            <!DOCTYPE root [
            <!ELEMENT root (sub*)>
            <!ELEMENT sub (#PCDATA)>
            <!ENTITY ent "an entity">
        ]>
        '''
        parser.feed(dtd+'<root><sub/><sub>this is &ent;</sub><sub/></root>')
        done = parser.close()

        self.assertEqual("DONE", done)
        self.assertEqual(["start-root", "start-sub", "end-sub", "start-sub",
                           "data-this is an entity",
                           "end-sub", "start-sub", "end-sub", "end-root"],
                          events)

    required_versions_ET['test_parser_target_entity_unknown'] = (1,3)
    def test_parser_target_entity_unknown(self):
        events = []
        class Target(object):
            def __init__(self):
                self._data = []
            def _flush_data(self):
                if self._data:
                    events.append("data-" + ''.join(self._data))
                    del self._data[:]
            def start(self, tag, attrib):
                self._flush_data()
                events.append("start-" + tag)
            def end(self, tag):
                self._flush_data()
                events.append("end-" + tag)
            def data(self, data):
                self._data.append(data)
            def close(self):
                self._flush_data()
                return "DONE"

        parser = self.XMLParser(target=Target())

        def feed():
            parser.feed('<root><sub/><sub>some &ent;</sub><sub/></root>')
            parser.close()

        self.assertRaises(self.etree.ParseError, feed)

    @et_needs_pyversion(3, 8, 0, 'alpha', 4)
    def test_parser_target_start_end_ns(self):
        class Builder(list):
            def start(self, tag, attrib):
                self.append(("start", tag))
            def end(self, tag):
                self.append(("end", tag))
            def data(self, text):
                pass
            def pi(self, target, data):
                self.append(("pi", target, data))
            def comment(self, data):
                self.append(("comment", data))
            def start_ns(self, prefix, uri):
                self.append(("start-ns", prefix, uri))
            def end_ns(self, prefix):
                self.append(("end-ns", prefix))

        builder = Builder()
        parser = self.etree.XMLParser(target=builder)
        parser.feed(textwrap.dedent("""\
            <?pi data?>
            <!-- comment -->
            <root xmlns='namespace'>
               <element key='value'>text</element>
               <element>text</element>tail
               <empty-element/>
            </root>
            """))
        self.assertEqual(builder, [
                ('pi', 'pi', 'data'),
                ('comment', ' comment '),
                ('start-ns', '', 'namespace'),
                ('start', '{namespace}root'),
                ('start', '{namespace}element'),
                ('end', '{namespace}element'),
                ('start', '{namespace}element'),
                ('end', '{namespace}element'),
                ('start', '{namespace}empty-element'),
                ('end', '{namespace}empty-element'),
                ('end', '{namespace}root'),
                ('end-ns', ''),
            ])

    @et_needs_pyversion(3, 8, 0, 'alpha', 4)
    def test_parser_target_end_ns(self):
        class Builder(list):
            def end_ns(self, prefix):
                self.append(("end-ns", prefix))

        builder = Builder()
        parser = self.etree.XMLParser(target=builder)
        parser.feed(textwrap.dedent("""\
            <?pi data?>
            <!-- comment -->
            <root xmlns='namespace' xmlns:p='pns'>
               <element key='value'>text</element>
               <p:element>text</p:element>tail
               <empty-element/>
            </root>
            """))
        self.assertEqual(builder, [
                ('end-ns', 'p'),
                ('end-ns', ''),
            ])

    def test_treebuilder(self):
        builder = self.etree.TreeBuilder()
        el = builder.start("root", {'a':'A', 'b':'B'})
        self.assertEqual("root", el.tag)
        self.assertEqual({'a':'A', 'b':'B'}, el.attrib)
        builder.data("ROOTTEXT")
        el = builder.start("child", {'x':'X', 'y':'Y'})
        self.assertEqual("child", el.tag)
        self.assertEqual({'x':'X', 'y':'Y'}, el.attrib)
        builder.data("CHILDTEXT")
        el = builder.end("child")
        self.assertEqual("child", el.tag)
        self.assertEqual({'x':'X', 'y':'Y'}, el.attrib)
        self.assertEqual("CHILDTEXT", el.text)
        self.assertEqual(None, el.tail)
        builder.data("CHILDTAIL")
        root = builder.end("root")

        self.assertEqual("root", root.tag)
        self.assertEqual("ROOTTEXT", root.text)
        self.assertEqual("CHILDTEXT", root[0].text)
        self.assertEqual("CHILDTAIL", root[0].tail)

    def test_treebuilder_target(self):
        parser = self.XMLParser(target=self.etree.TreeBuilder())
        parser.feed('<root>ROOTTEXT<child>CHILDTEXT</child>CHILDTAIL</root>')
        root = parser.close()

        self.assertEqual("root", root.tag)
        self.assertEqual("ROOTTEXT", root.text)
        self.assertEqual("CHILDTEXT", root[0].text)
        self.assertEqual("CHILDTAIL", root[0].tail)

    @et_needs_pyversion(3, 8, 0, 'alpha', 4)
    def test_treebuilder_comment(self):
        ET = self.etree
        b = ET.TreeBuilder()
        self.assertEqual(b.comment('ctext').tag, ET.Comment)
        self.assertEqual(b.comment('ctext').text, 'ctext')

        b = ET.TreeBuilder(comment_factory=ET.Comment)
        self.assertEqual(b.comment('ctext').tag, ET.Comment)
        self.assertEqual(b.comment('ctext').text, 'ctext')

        #b = ET.TreeBuilder(comment_factory=len)
        #self.assertEqual(b.comment('ctext'), len('ctext'))

    @et_needs_pyversion(3, 8, 0, 'alpha', 4)
    def test_treebuilder_pi(self):
        ET = self.etree
        is_lxml = ET.__name__ == 'lxml.etree'

        b = ET.TreeBuilder()
        self.assertEqual(b.pi('target', None).tag, ET.PI)
        if is_lxml:
            self.assertEqual(b.pi('target', None).target, 'target')
        else:
            self.assertEqual(b.pi('target', None).text, 'target')

        b = ET.TreeBuilder(pi_factory=ET.PI)
        self.assertEqual(b.pi('target').tag, ET.PI)
        if is_lxml:
            self.assertEqual(b.pi('target').target, "target")
        else:
            self.assertEqual(b.pi('target').text, "target")
        self.assertEqual(b.pi('pitarget', ' text ').tag, ET.PI)
        if is_lxml:
            self.assertEqual(b.pi('pitarget', ' text ').target, "pitarget")
            self.assertEqual(b.pi('pitarget', ' text ').text, " text ")
        else:
            self.assertEqual(b.pi('pitarget', ' text ').text, "pitarget  text ")

        #b = ET.TreeBuilder(pi_factory=lambda target, text: (len(target), text))
        #self.assertEqual(b.pi('target'), (len('target'), None))
        #self.assertEqual(b.pi('pitarget', ' text '), (len('pitarget'), ' text '))

    def test_late_tail(self):
        # Issue #37399: The tail of an ignored comment could overwrite the text before it.
        ET = self.etree
        class TreeBuilderSubclass(ET.TreeBuilder):
            pass

        if ET.__name__ == 'lxml.etree':
            def assert_content(a):
                self.assertEqual(a.text, "text")
                self.assertEqual(a[0].tail, "tail")
        else:
            def assert_content(a):
                self.assertEqual(a.text, "texttail")

        xml = "<a>text<!-- comment -->tail</a>"
        a = ET.fromstring(xml)
        assert_content(a)

        parser = ET.XMLParser(target=TreeBuilderSubclass())
        parser.feed(xml)
        a = parser.close()
        assert_content(a)

        xml = "<a>text<?pi data?>tail</a>"
        a = ET.fromstring(xml)
        assert_content(a)

        xml = "<a>text<?pi data?>tail</a>"
        parser = ET.XMLParser(target=TreeBuilderSubclass())
        parser.feed(xml)
        a = parser.close()
        assert_content(a)

    @et_needs_pyversion(3, 8, 0, 'alpha', 4)
    def test_late_tail_mix_pi_comments(self):
        # Issue #37399: The tail of an ignored comment could overwrite the text before it.
        # Test appending tails to comments/pis.
        ET = self.etree
        class TreeBuilderSubclass(ET.TreeBuilder):
            pass

        xml = "<a>text<?pi1?> <!-- comment -->\n<?pi2?>tail</a>"
        parser = ET.XMLParser(target=ET.TreeBuilder(insert_comments=True, insert_pis=False))
        parser.feed(xml)
        a = parser.close()
        self.assertEqual(a[0].text, ' comment ')
        self.assertEqual(a[0].tail, '\ntail')
        self.assertEqual(a.text, "text ")

        parser = ET.XMLParser(target=TreeBuilderSubclass(insert_comments=True, insert_pis=False))
        parser.feed(xml)
        a = parser.close()
        self.assertEqual(a[0].text, ' comment ')
        self.assertEqual(a[0].tail, '\ntail')
        self.assertEqual(a.text, "text ")

        xml = "<a>text<!-- comment -->\n<?pi data?>tail</a>"
        parser = ET.XMLParser(target=ET.TreeBuilder(insert_pis=True, insert_comments=False))
        parser.feed(xml)
        a = parser.close()
        self.assertEqual(a[0].text[-4:], 'data')
        self.assertEqual(a[0].tail, 'tail')
        self.assertEqual(a.text, "text\n")

        parser = ET.XMLParser(target=TreeBuilderSubclass(insert_pis=True, insert_comments=False))
        parser.feed(xml)
        a = parser.close()
        self.assertEqual(a[0].text[-4:], 'data')
        self.assertEqual(a[0].tail, 'tail')
        self.assertEqual(a.text, "text\n")

    # helper methods

    def _writeElement(self, element, encoding='us-ascii'):
        """Write out element for comparison.
        """
        data = self.etree.tostring(element, encoding=encoding)
        return canonicalize(data)

    def _writeElementFile(self, element, encoding='us-ascii'):
        """Write out element for comparison, using real file.
        """
        ElementTree = self.etree.ElementTree
        with tmpfile() as filename:
            with open(filename, 'wb') as f:
                tree = ElementTree(element=element)
                tree.write(f, encoding=encoding)
            with open(filename, 'rb') as f:
                data = f.read()
        return canonicalize(data)

    def assertXML(self, expected, element, encoding='us-ascii'):
        """Writes element out and checks whether it is expected.

        Does this two ways; once using BytesIO, once using a real file.
        """
        if isinstance(expected, unicode):
            expected = expected.encode(encoding)
        self.assertEqual(expected, self._writeElement(element, encoding))
        self.assertEqual(expected, self._writeElementFile(element, encoding))

    def assertEncodingDeclaration(self, result, encoding):
        "Checks if the result XML byte string specifies the encoding."
        enc_re = r"<\?xml[^>]+ encoding=[\"']([^\"']+)[\"']"
        if isinstance(result, str):
            has_encoding = re.compile(enc_re).match
        else:
            has_encoding = re.compile(_bytes(enc_re)).match
        self.assertTrue(has_encoding(result))
        result_encoding = has_encoding(result).group(1)
        self.assertEqual(result_encoding.upper(), encoding.upper())

    def _rootstring(self, tree):
        return self.etree.tostring(tree.getroot()).replace(
            _bytes(' '), _bytes('')).replace(_bytes('\n'), _bytes(''))

    def _check_element_tree(self, tree):
        self._check_element(tree.getroot())

    def _check_element(self, element):
        self.assertTrue(hasattr(element, 'tag'))
        self.assertTrue(hasattr(element, 'attrib'))
        self.assertTrue(hasattr(element, 'text'))
        self.assertTrue(hasattr(element, 'tail'))
        self._check_string(element.tag)
        self._check_mapping(element.attrib)
        if element.text is not None:
            self._check_string(element.text)
        if element.tail is not None:
            self._check_string(element.tail)

    def _check_string(self, string):
        len(string)
        for char in string:
            self.assertEqual(1, len(char))
        new_string = string + ""
        new_string = string + " "
        string[:0]

    def _check_mapping(self, mapping):
        len(mapping)
        keys = mapping.keys()
        values = mapping.values()
        items = mapping.items()
        for key in keys:
            item = mapping[key]
        mapping["key"] = "value"
        self.assertEqual("value", mapping["key"])


class _ElementSlicingTest(unittest.TestCase):
    etree = None

    def _elem_tags(self, elemlist):
        return [e.tag for e in elemlist]

    def _subelem_tags(self, elem):
        return self._elem_tags(list(elem))

    def _make_elem_with_children(self, numchildren):
        """Create an Element with a tag 'a', with the given amount of children
           named 'a0', 'a1' ... and so on.

        """
        e = self.etree.Element('a')
        for i in range(numchildren):
            self.etree.SubElement(e, 'a%s' % i)
        return e

    def test_getslice_single_index(self):
        e = self._make_elem_with_children(10)

        self.assertEqual(e[1].tag, 'a1')
        self.assertEqual(e[-2].tag, 'a8')

        self.assertRaises(IndexError, lambda: e[12])
        self.assertRaises(IndexError, lambda: e[-12])

    def test_getslice_range(self):
        e = self._make_elem_with_children(6)

        self.assertEqual(self._elem_tags(e[3:]), ['a3', 'a4', 'a5'])
        self.assertEqual(self._elem_tags(e[3:6]), ['a3', 'a4', 'a5'])
        self.assertEqual(self._elem_tags(e[3:16]), ['a3', 'a4', 'a5'])
        self.assertEqual(self._elem_tags(e[3:5]), ['a3', 'a4'])
        self.assertEqual(self._elem_tags(e[3:-1]), ['a3', 'a4'])
        self.assertEqual(self._elem_tags(e[:2]), ['a0', 'a1'])

    def test_getslice_steps(self):
        e = self._make_elem_with_children(10)

        self.assertEqual(self._elem_tags(e[8:10:1]), ['a8', 'a9'])
        self.assertEqual(self._elem_tags(e[::3]), ['a0', 'a3', 'a6', 'a9'])
        self.assertEqual(self._elem_tags(e[::8]), ['a0', 'a8'])
        self.assertEqual(self._elem_tags(e[1::8]), ['a1', 'a9'])
        self.assertEqual(self._elem_tags(e[3::sys.maxsize]), ['a3'])
        self.assertEqual(self._elem_tags(e[3::sys.maxsize<<64]), ['a3'])

    def test_getslice_negative_steps(self):
        e = self._make_elem_with_children(4)

        self.assertEqual(self._elem_tags(e[::-1]), ['a3', 'a2', 'a1', 'a0'])
        self.assertEqual(self._elem_tags(e[::-2]), ['a3', 'a1'])
        self.assertEqual(self._elem_tags(e[3::-sys.maxsize]), ['a3'])
        self.assertEqual(self._elem_tags(e[3::-sys.maxsize-1]), ['a3'])
        self.assertEqual(self._elem_tags(e[3::-sys.maxsize<<64]), ['a3'])

    def test_delslice(self):
        e = self._make_elem_with_children(4)
        del e[0:2]
        self.assertEqual(self._subelem_tags(e), ['a2', 'a3'])

        e = self._make_elem_with_children(4)
        del e[0:]
        self.assertEqual(self._subelem_tags(e), [])

        e = self._make_elem_with_children(4)
        del e[::-1]
        self.assertEqual(self._subelem_tags(e), [])

        e = self._make_elem_with_children(4)
        del e[::-2]
        self.assertEqual(self._subelem_tags(e), ['a0', 'a2'])

        e = self._make_elem_with_children(4)
        del e[1::2]
        self.assertEqual(self._subelem_tags(e), ['a0', 'a2'])

        e = self._make_elem_with_children(2)
        del e[::2]
        self.assertEqual(self._subelem_tags(e), ['a1'])

    def test_setslice_single_index(self):
        e = self._make_elem_with_children(4)
        e[1] = self.etree.Element('b')
        self.assertEqual(self._subelem_tags(e), ['a0', 'b', 'a2', 'a3'])

        e[-2] = self.etree.Element('c')
        self.assertEqual(self._subelem_tags(e), ['a0', 'b', 'c', 'a3'])

        with self.assertRaises(IndexError):
            e[5] = self.etree.Element('d')
        with self.assertRaises(IndexError):
            e[-5] = self.etree.Element('d')
        self.assertEqual(self._subelem_tags(e), ['a0', 'b', 'c', 'a3'])

    def test_setslice_range(self):
        e = self._make_elem_with_children(4)
        e[1:3] = [self.etree.Element('b%s' % i) for i in range(2)]
        self.assertEqual(self._subelem_tags(e), ['a0', 'b0', 'b1', 'a3'])

        e = self._make_elem_with_children(4)
        e[1:3] = [self.etree.Element('b')]
        self.assertEqual(self._subelem_tags(e), ['a0', 'b', 'a3'])

        e = self._make_elem_with_children(4)
        e[1:3] = [self.etree.Element('b%s' % i) for i in range(3)]
        self.assertEqual(self._subelem_tags(e), ['a0', 'b0', 'b1', 'b2', 'a3'])

    def test_setslice_steps(self):
        e = self._make_elem_with_children(6)
        e[1:5:2] = [self.etree.Element('b%s' % i) for i in range(2)]
        self.assertEqual(self._subelem_tags(e), ['a0', 'b0', 'a2', 'b1', 'a4', 'a5'])

        e = self._make_elem_with_children(6)
        with self.assertRaises(ValueError):
            e[1:5:2] = [self.etree.Element('b')]
        with self.assertRaises(ValueError):
            e[1:5:2] = [self.etree.Element('b%s' % i) for i in range(3)]
        with self.assertRaises(ValueError):
            e[1:5:2] = []
        self.assertEqual(self._subelem_tags(e), ['a0', 'a1', 'a2', 'a3', 'a4', 'a5'])

        e = self._make_elem_with_children(4)
        e[1::sys.maxsize] = [self.etree.Element('b')]
        self.assertEqual(self._subelem_tags(e), ['a0', 'b', 'a2', 'a3'])
        e[1::sys.maxsize<<64] = [self.etree.Element('c')]
        self.assertEqual(self._subelem_tags(e), ['a0', 'c', 'a2', 'a3'])

    def test_setslice_negative_steps(self):
        e = self._make_elem_with_children(4)
        e[2:0:-1] = [self.etree.Element('b%s' % i) for i in range(2)]
        self.assertEqual(self._subelem_tags(e), ['a0', 'b1', 'b0', 'a3'])

        e = self._make_elem_with_children(4)
        with self.assertRaises(ValueError):
            e[2:0:-1] = [self.etree.Element('b')]
        with self.assertRaises(ValueError):
            e[2:0:-1] = [self.etree.Element('b%s' % i) for i in range(3)]
        with self.assertRaises(ValueError):
            e[2:0:-1] = []
        self.assertEqual(self._subelem_tags(e), ['a0', 'a1', 'a2', 'a3'])

        e = self._make_elem_with_children(4)
        e[1::-sys.maxsize] = [self.etree.Element('b')]
        self.assertEqual(self._subelem_tags(e), ['a0', 'b', 'a2', 'a3'])
        e[1::-sys.maxsize-1] = [self.etree.Element('c')]
        self.assertEqual(self._subelem_tags(e), ['a0', 'c', 'a2', 'a3'])
        e[1::-sys.maxsize<<64] = [self.etree.Element('d')]
        self.assertEqual(self._subelem_tags(e), ['a0', 'd', 'a2', 'a3'])


class _XMLPullParserTest(unittest.TestCase):
    etree = None

    def _close_and_return_root(self, parser):
        if 'ElementTree' in self.etree.__name__:
            # ElementTree's API is a bit unwieldy in Py3.4
            root = parser._close_and_return_root()
        else:
            root = parser.close()
        return root

    def _feed(self, parser, data, chunk_size=None):
        if chunk_size is None:
            parser.feed(data)
        else:
            for i in range(0, len(data), chunk_size):
                parser.feed(data[i:i+chunk_size])

    def assert_events(self, parser, expected, max_events=None):
        self.assertEqual(
            [(event, (elem.tag, elem.text))
             for event, elem in islice(parser.read_events(), max_events)],
            expected)

    def assert_event_tuples(self, parser, expected, max_events=None):
        self.assertEqual(
            list(islice(parser.read_events(), max_events)),
            expected)

    def assert_event_tags(self, parser, expected, max_events=None):
        events = islice(parser.read_events(), max_events)
        self.assertEqual([(action, elem.tag) for action, elem in events],
                         expected)

    def test_simple_xml(self, chunk_size=None):
        parser = self.etree.XMLPullParser()
        self.assert_event_tags(parser, [])
        self._feed(parser, "<!-- comment -->\n", chunk_size)
        self.assert_event_tags(parser, [])
        self._feed(parser,
                   "<root>\n  <element key='value'>text</element",
                   chunk_size)
        self.assert_event_tags(parser, [])
        self._feed(parser, ">\n", chunk_size)
        self.assert_event_tags(parser, [('end', 'element')])
        self._feed(parser, "<element>text</element>tail\n", chunk_size)
        self._feed(parser, "<empty-element/>\n", chunk_size)
        self.assert_event_tags(parser, [
            ('end', 'element'),
            ('end', 'empty-element'),
            ])
        self._feed(parser, "</root>\n", chunk_size)
        self.assert_event_tags(parser, [('end', 'root')])
        root = self._close_and_return_root(parser)
        self.assertEqual(root.tag, 'root')

    def test_simple_xml_chunk_1(self):
        if self.etree is not etree and (pyexpat.version_info >= (2, 6, 0) or IS_PYPY):
            raise unittest.SkipTest(
                "Feeding the parser by too small chunks defers parsing"
            )
        self.test_simple_xml(chunk_size=1)

    def test_simple_xml_chunk_5(self):
        if self.etree is not etree and (pyexpat.version_info >= (2, 6, 0) or IS_PYPY):
            raise unittest.SkipTest(
                "Feeding the parser by too small chunks defers parsing"
            )
        self.test_simple_xml(chunk_size=5)

    def test_simple_xml_chunk_22(self):
        self.test_simple_xml(chunk_size=22)

    def test_feed_while_iterating(self):
        parser = self.etree.XMLPullParser()
        it = parser.read_events()
        self._feed(parser, "<root>\n  <element key='value'>text</element>\n")
        action, elem = next(it)
        self.assertEqual((action, elem.tag), ('end', 'element'))
        self._feed(parser, "</root>\n")
        action, elem = next(it)
        self.assertEqual((action, elem.tag), ('end', 'root'))
        with self.assertRaises(StopIteration):
            next(it)

    def test_simple_xml_with_ns(self):
        parser = self.etree.XMLPullParser()
        self.assert_event_tags(parser, [])
        self._feed(parser, "<!-- comment -->\n")
        self.assert_event_tags(parser, [])
        self._feed(parser, "<root xmlns='namespace'>\n")
        self.assert_event_tags(parser, [])
        self._feed(parser, "<element key='value'>text</element")
        self.assert_event_tags(parser, [])
        self._feed(parser, ">\n")
        self.assert_event_tags(parser, [('end', '{namespace}element')])
        self._feed(parser, "<element>text</element>tail\n")
        self._feed(parser, "<empty-element/>\n")
        self.assert_event_tags(parser, [
            ('end', '{namespace}element'),
            ('end', '{namespace}empty-element'),
            ])
        self._feed(parser, "</root>\n")
        self.assert_event_tags(parser, [('end', '{namespace}root')])
        root = self._close_and_return_root(parser)
        self.assertEqual(root.tag, '{namespace}root')

    def test_ns_events(self):
        parser = self.etree.XMLPullParser(events=('start-ns', 'end-ns'))
        self._feed(parser, "<!-- comment -->\n")
        self._feed(parser, "<root xmlns='namespace'>\n")
        self.assertEqual(
            list(parser.read_events()),
            [('start-ns', ('', 'namespace'))])
        self._feed(parser, "<element key='value'>text</element")
        self._feed(parser, ">\n")
        self._feed(parser, "<element>text</element>tail\n")
        self._feed(parser, "<empty-element/>\n")
        self._feed(parser, "</root>\n")
        self.assertEqual(list(parser.read_events()), [('end-ns', None)])
        parser.close()

    def test_ns_events_end_ns_only(self):
        parser = self.etree.XMLPullParser(events=['end-ns'])
        self._feed(parser, "<!-- comment -->\n")
        self._feed(parser, "<root xmlns='namespace' xmlns:a='abc' xmlns:b='xyz'>\n")
        self.assertEqual(list(parser.read_events()), [])
        self._feed(parser, "<a:element key='value'>text</a:element")
        self._feed(parser, ">\n")
        self._feed(parser, "<b:element>text</b:element>tail\n")
        self._feed(parser, "<empty-element/>\n")
        self.assertEqual(list(parser.read_events()), [])
        self._feed(parser, "</root>\n")
        self.assertEqual(list(parser.read_events()), [
            ('end-ns', None),
            ('end-ns', None),
            ('end-ns', None),
        ])
        parser.close()

    @et_needs_pyversion(3,8)
    def test_ns_events_start(self):
        parser = self.etree.XMLPullParser(events=('start-ns', 'start', 'end'))
        self._feed(parser, "<tag xmlns='abc' xmlns:p='xyz'>\n")
        self.assert_event_tuples(parser, [
            ('start-ns', ('', 'abc')),
            ('start-ns', ('p', 'xyz')),
        ], max_events=2)
        self.assert_event_tags(parser, [
            ('start', '{abc}tag'),
        ], max_events=1)

        self._feed(parser, "<child />\n")
        self.assert_event_tags(parser, [
            ('start', '{abc}child'),
            ('end', '{abc}child'),
        ])

        self._feed(parser, "</tag>\n")
        parser.close()
        self.assert_event_tags(parser, [
            ('end', '{abc}tag'),
        ])

    @et_needs_pyversion(3,8)
    def test_ns_events_start_end(self):
        parser = self.etree.XMLPullParser(events=('start-ns', 'start', 'end', 'end-ns'))
        self._feed(parser, "<tag xmlns='abc' xmlns:p='xyz'>\n")
        self.assert_event_tuples(parser, [
            ('start-ns', ('', 'abc')),
            ('start-ns', ('p', 'xyz')),
        ], max_events=2)
        self.assert_event_tags(parser, [
            ('start', '{abc}tag'),
        ], max_events=1)

        self._feed(parser, "<child />\n")
        self.assert_event_tags(parser, [
            ('start', '{abc}child'),
            ('end', '{abc}child'),
        ])

        self._feed(parser, "</tag>\n")
        parser.close()
        self.assert_event_tags(parser, [
            ('end', '{abc}tag'),
        ], max_events=1)
        self.assert_event_tuples(parser, [
            ('end-ns', None),
            ('end-ns', None),
        ])

    def test_events(self):
        parser = self.etree.XMLPullParser(events=())
        self._feed(parser, "<root/>\n")
        self.assert_event_tags(parser, [])

        parser = self.etree.XMLPullParser(events=('start', 'end'))
        self._feed(parser, "<!-- text here -->\n")
        self.assert_events(parser, [])

        parser = self.etree.XMLPullParser(events=('start', 'end'))
        self._feed(parser, "<root>\n")
        self.assert_event_tags(parser, [('start', 'root')])
        self._feed(parser, "<element key='value'>text</element")
        self.assert_event_tags(parser, [('start', 'element')])
        self._feed(parser, ">\n")
        self.assert_event_tags(parser, [('end', 'element')])
        self._feed(parser,
                   "<element xmlns='foo'>text<empty-element/></element>tail\n")
        self.assert_event_tags(parser, [
            ('start', '{foo}element'),
            ('start', '{foo}empty-element'),
            ('end', '{foo}empty-element'),
            ('end', '{foo}element'),
            ])
        self._feed(parser, "</root>")
        root = self._close_and_return_root(parser)
        self.assert_event_tags(parser, [('end', 'root')])
        self.assertEqual(root.tag, 'root')

        parser = self.etree.XMLPullParser(events=('start',))
        self._feed(parser, "<!-- comment -->\n")
        self.assert_event_tags(parser, [])
        self._feed(parser, "<root>\n")
        self.assert_event_tags(parser, [('start', 'root')])
        self._feed(parser, "<element key='value'>text</element")
        self.assert_event_tags(parser, [('start', 'element')])
        self._feed(parser, ">\n")
        self.assert_event_tags(parser, [])
        self._feed(parser,
                   "<element xmlns='foo'>text<empty-element/></element>tail\n")
        self.assert_event_tags(parser, [
            ('start', '{foo}element'),
            ('start', '{foo}empty-element'),
            ])
        self._feed(parser, "</root>")
        root = self._close_and_return_root(parser)
        self.assertEqual(root.tag, 'root')

    @et_needs_pyversion(3, 8, 0, 'alpha', 4)
    def test_events_comment(self):
        parser = self.etree.XMLPullParser(events=('start', 'comment', 'end'))
        self._feed(parser, "<!-- text here -->\n")
        self.assert_events(parser, [('comment', (self.etree.Comment, ' text here '))])
        self._feed(parser, "<!-- more text here -->\n")
        self.assert_events(parser, [('comment', (self.etree.Comment, ' more text here '))])
        self._feed(parser, "<root-tag>text")
        self.assert_event_tags(parser, [('start', 'root-tag')])
        self._feed(parser, "<!-- inner comment-->\n")
        self.assert_events(parser, [('comment', (self.etree.Comment, ' inner comment'))])
        self._feed(parser, "</root-tag>\n")
        self.assert_event_tags(parser, [('end', 'root-tag')])
        self._feed(parser, "<!-- outer comment -->\n")
        self.assert_events(parser, [('comment', (self.etree.Comment, ' outer comment '))])

        parser = self.etree.XMLPullParser(events=('comment',))
        self._feed(parser, "<!-- text here -->\n")
        self.assert_events(parser, [('comment', (self.etree.Comment, ' text here '))])

    @et_needs_pyversion(3, 8, 0, 'alpha', 4)
    def test_events_pi(self):
        # Note: lxml's PIs have target+text, ET's PIs have both in "text"
        parser = self.etree.XMLPullParser(events=('start', 'pi', 'end'))
        self._feed(parser, "<?pitarget?>\n")
        self.assert_event_tags(parser, [('pi', self.etree.PI)])
        parser = self.etree.XMLPullParser(events=('pi',))
        self._feed(parser, "<?pitarget some text ?>\n")
        self.assert_event_tags(parser, [('pi', self.etree.PI)])

    def test_events_sequence(self):
        # Test that events can be some sequence that's not just a tuple or list
        eventset = {'end', 'start'}
        parser = self.etree.XMLPullParser(events=eventset)
        self._feed(parser, "<foo>bar</foo>")
        self.assert_event_tags(parser, [('start', 'foo'), ('end', 'foo')])

        class DummyIter(object):
            def __init__(self):
                self.events = iter(['start', 'end', 'start-ns'])
            def __iter__(self):
                return self
            def __next__(self):
                return next(self.events)
            def next(self):
                return next(self.events)

        parser = self.etree.XMLPullParser(events=DummyIter())
        self._feed(parser, "<foo>bar</foo>")
        self.assert_event_tags(parser, [('start', 'foo'), ('end', 'foo')])

    def test_unknown_event(self):
        with self.assertRaises(ValueError):
            self.etree.XMLPullParser(events=('start', 'end', 'bogus'))


class _C14NTest(unittest.TestCase):
    etree = None
    maxDiff = None

    if not hasattr(unittest.TestCase, 'subTest'):
        @contextmanager
        def subTest(self, name, **kwargs):
            try:
                yield
            except unittest.SkipTest:
                raise
            except Exception as e:
                print("Subtest {} failed: {}".format(name, e))
                raise

    def _canonicalize(self, input_file, **options):
        return self.etree.canonicalize(from_file=input_file, **options)

    #
    # simple roundtrip tests (from c14n.py)

    def c14n_roundtrip(self, xml, **options):
        return self.etree.canonicalize(xml, **options)

    def test_simple_roundtrip(self):
        c14n_roundtrip = self.c14n_roundtrip
        # Basics
        self.assertEqual(c14n_roundtrip("<doc/>"), '<doc></doc>')
        self.assertEqual(c14n_roundtrip("<doc xmlns='uri'/>"), # FIXME
                '<doc xmlns="uri"></doc>')
        self.assertEqual(c14n_roundtrip("<prefix:doc xmlns:prefix='uri'/>"),
            '<prefix:doc xmlns:prefix="uri"></prefix:doc>')
        self.assertEqual(c14n_roundtrip("<doc xmlns:prefix='uri'><prefix:bar/></doc>"),
            '<doc><prefix:bar xmlns:prefix="uri"></prefix:bar></doc>')
        self.assertEqual(c14n_roundtrip("<elem xmlns:wsu='http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd' xmlns:SOAP-ENV='http://schemas.xmlsoap.org/soap/envelope/' />"),
            '<elem></elem>')

        # C14N spec
        self.assertEqual(c14n_roundtrip("<doc>Hello, world!<!-- Comment 1 --></doc>"),
            '<doc>Hello, world!</doc>')
        self.assertEqual(c14n_roundtrip("<value>&#x32;</value>"),
            '<value>2</value>')
        self.assertEqual(c14n_roundtrip('<compute><![CDATA[value>"0" && value<"10" ?"valid":"error"]]></compute>'),
            '<compute>value&gt;"0" &amp;&amp; value&lt;"10" ?"valid":"error"</compute>')
        self.assertEqual(c14n_roundtrip('''<compute expr='value>"0" &amp;&amp; value&lt;"10" ?"valid":"error"'>valid</compute>'''),
            '<compute expr="value>&quot;0&quot; &amp;&amp; value&lt;&quot;10&quot; ?&quot;valid&quot;:&quot;error&quot;">valid</compute>')
        self.assertEqual(c14n_roundtrip("<norm attr=' &apos;   &#x20;&#13;&#xa;&#9;   &apos; '/>"),
            '<norm attr=" \'    &#xD;&#xA;&#x9;   \' "></norm>')
        self.assertEqual(c14n_roundtrip("<normNames attr='   A   &#x20;&#13;&#xa;&#9;   B   '/>"),
            '<normNames attr="   A    &#xD;&#xA;&#x9;   B   "></normNames>')
        self.assertEqual(c14n_roundtrip("<normId id=' &apos;   &#x20;&#13;&#xa;&#9;   &apos; '/>"),
            '<normId id=" \'    &#xD;&#xA;&#x9;   \' "></normId>')

        # fragments from PJ's tests
        #self.assertEqual(c14n_roundtrip("<doc xmlns:x='http://example.com/x' xmlns='http://example.com/default'><b y:a1='1' xmlns='http://example.com/default' a3='3' xmlns:y='http://example.com/y' y:a2='2'/></doc>"),
        #'<doc xmlns:x="http://example.com/x"><b xmlns:y="http://example.com/y" a3="3" y:a1="1" y:a2="2"></b></doc>')

    @et_needs_pyversion(3, 8, 7)
    @et_exclude_pyversion(3, 9, 0)
    def test_c14n_namespaces(self):
        c14n_roundtrip = self.c14n_roundtrip
        # Namespace issues
        # https://bugs.launchpad.net/lxml/+bug/1869455
        xml = '<X xmlns="http://nps/a"><Y targets="abc,xyz"></Y></X>'
        self.assertEqual(c14n_roundtrip(xml), xml)
        xml = '<X xmlns="http://nps/a"><Y xmlns="http://nsp/b" targets="abc,xyz"></Y></X>'
        self.assertEqual(c14n_roundtrip(xml), xml)
        xml = '<X xmlns="http://nps/a"><Y xmlns:b="http://nsp/b" b:targets="abc,xyz"></Y></X>'
        self.assertEqual(c14n_roundtrip(xml), xml)

    def test_c14n_exclusion(self):
        c14n_roundtrip = self.c14n_roundtrip
        xml = textwrap.dedent("""\
        <root xmlns:x="http://example.com/x">
            <a x:attr="attrx">
                <b>abtext</b>
            </a>
            <b>btext</b>
            <c>
                <x:d>dtext</x:d>
            </c>
        </root>
        """)
        self.assertEqual(
            c14n_roundtrip(xml, strip_text=True),
            '<root>'
            '<a xmlns:x="http://example.com/x" x:attr="attrx"><b>abtext</b></a>'
            '<b>btext</b>'
            '<c><x:d xmlns:x="http://example.com/x">dtext</x:d></c>'
            '</root>')
        self.assertEqual(
            c14n_roundtrip(xml, strip_text=True, exclude_attrs=['{http://example.com/x}attr']),
            '<root>'
            '<a><b>abtext</b></a>'
            '<b>btext</b>'
            '<c><x:d xmlns:x="http://example.com/x">dtext</x:d></c>'
            '</root>')
        self.assertEqual(
            c14n_roundtrip(xml, strip_text=True, exclude_tags=['{http://example.com/x}d']),
            '<root>'
            '<a xmlns:x="http://example.com/x" x:attr="attrx"><b>abtext</b></a>'
            '<b>btext</b>'
            '<c></c>'
            '</root>')
        self.assertEqual(
            c14n_roundtrip(xml, strip_text=True, exclude_attrs=['{http://example.com/x}attr'],
                           exclude_tags=['{http://example.com/x}d']),
            '<root>'
            '<a><b>abtext</b></a>'
            '<b>btext</b>'
            '<c></c>'
            '</root>')
        self.assertEqual(
            c14n_roundtrip(xml, strip_text=True, exclude_tags=['a', 'b']),
            '<root>'
            '<c><x:d xmlns:x="http://example.com/x">dtext</x:d></c>'
            '</root>')
        self.assertEqual(
            c14n_roundtrip(xml, exclude_tags=['a', 'b']),
            '<root>\n'
            '    \n'
            '    \n'
            '    <c>\n'
            '        <x:d xmlns:x="http://example.com/x">dtext</x:d>\n'
            '    </c>\n'
            '</root>')
        self.assertEqual(
            c14n_roundtrip(xml, strip_text=True, exclude_tags=['{http://example.com/x}d', 'b']),
            '<root>'
            '<a xmlns:x="http://example.com/x" x:attr="attrx"></a>'
            '<c></c>'
            '</root>')
        self.assertEqual(
            c14n_roundtrip(xml, exclude_tags=['{http://example.com/x}d', 'b']),
            '<root>\n'
            '    <a xmlns:x="http://example.com/x" x:attr="attrx">\n'
            '        \n'
            '    </a>\n'
            '    \n'
            '    <c>\n'
            '        \n'
            '    </c>\n'
            '</root>')

    #
    # basic method=c14n tests from the c14n 2.0 specification.  uses
    # test files under xmltestdata/c14n-20.

    # note that this uses generated C14N versions of the standard ET.write
    # output, not roundtripped C14N (see above).

    def test_xml_c14n2(self):
        datadir = os.path.join(os.path.dirname(__file__), "c14n-20")
        full_path = partial(os.path.join, datadir)

        files = [filename[:-4] for filename in sorted(os.listdir(datadir))
                 if filename.endswith('.xml')]
        input_files = [
            filename for filename in files
            if filename.startswith('in')
        ]
        configs = {
            filename: {
                # <c14n2:PrefixRewrite>sequential</c14n2:PrefixRewrite>
                option.tag.split('}')[-1]: ((option.text or '').strip(), option)
                for option in self.etree.parse(full_path(filename) + ".xml").getroot()
            }
            for filename in files
            if filename.startswith('c14n')
        }

        tests = {
            input_file: [
                (filename, configs[filename.rsplit('_', 1)[-1]])
                for filename in files
                if filename.startswith('out_%s_' % input_file)
                and filename.rsplit('_', 1)[-1] in configs
            ]
            for input_file in input_files
        }

        # Make sure we found all test cases.
        self.assertEqual(30, len([
            output_file for output_files in tests.values()
            for output_file in output_files]))

        def get_option(config, option_name, default=None):
            return config.get(option_name, (default, ()))[0]

        for input_file, output_files in tests.items():
            for output_file, config in output_files:
                keep_comments = get_option(
                    config, 'IgnoreComments') == 'true'  # no, it's right :)
                strip_text = get_option(
                    config, 'TrimTextNodes') == 'true'
                rewrite_prefixes = get_option(
                    config, 'PrefixRewrite') == 'sequential'
                if 'QNameAware' in config:
                    qattrs = [
                        "{%s}%s" % (el.get('NS'), el.get('Name'))
                        for el in config['QNameAware'][1].findall(
                            '{http://www.w3.org/2010/xml-c14n2}QualifiedAttr')
                    ]
                    qtags = [
                        "{%s}%s" % (el.get('NS'), el.get('Name'))
                        for el in config['QNameAware'][1].findall(
                            '{http://www.w3.org/2010/xml-c14n2}Element')
                    ]
                else:
                    qtags = qattrs = None

                # Build subtest description from config.
                config_descr = ','.join(
                    "%s=%s" % (name, value or ','.join(c.tag.split('}')[-1] for c in children))
                    for name, (value, children) in sorted(config.items())
                )

                with self.subTest("{}({})".format(output_file, config_descr)):
                    if input_file == 'inNsRedecl' and not rewrite_prefixes:
                        self.skipTest(
                            "Redeclared namespace handling is not supported in {}".format(
                                output_file))
                    if input_file == 'inNsSuperfluous' and not rewrite_prefixes:
                        self.skipTest(
                            "Redeclared namespace handling is not supported in {}".format(
                                output_file))
                    if 'QNameAware' in config and config['QNameAware'][1].find(
                            '{http://www.w3.org/2010/xml-c14n2}XPathElement') is not None:
                        self.skipTest(
                            "QName rewriting in XPath text is not supported in {}".format(
                                output_file))

                    f = full_path(input_file + ".xml")
                    if input_file == 'inC14N5':
                        # Hack: avoid setting up external entity resolution in the parser.
                        with open(full_path('world.txt'), 'rb') as entity_file:
                            with open(f, 'rb') as f:
                                f = io.BytesIO(f.read().replace(b'&ent2;', entity_file.read().strip()))

                    text = self._canonicalize(
                        f,
                        with_comments=keep_comments,
                        strip_text=strip_text,
                        rewrite_prefixes=rewrite_prefixes,
                        qname_aware_tags=qtags, qname_aware_attrs=qattrs)

                    with io.open(full_path(output_file + ".xml"), 'r', encoding='utf8') as f:
                        expected = f.read()
                    if input_file == 'inC14N3' and self.etree is not etree:
                        # FIXME: cET resolves default attributes but ET does not!
                        expected = expected.replace(' attr="default"', '')
                        text = text.replace(' attr="default"', '')
                    self.assertEqual(expected, text)


if etree:
    class ETreeTestCase(_ETreeTestCaseBase):
        etree = etree

    class ETreePullTestCase(_XMLPullParserTest):
        etree = etree

    class ETreeElementSlicingTest(_ElementSlicingTest):
        etree = etree

    class ETreeC14NTest(_C14NTest):
        etree = etree

    class ETreeC14N2WriteTest(ETreeC14NTest):
        def _canonicalize(self, input_file, with_comments=True, strip_text=False,
                          rewrite_prefixes=False, qname_aware_tags=None, qname_aware_attrs=None,
                          **options):
            if rewrite_prefixes or qname_aware_attrs or qname_aware_tags:
                self.skipTest("C14N 2.0 feature not supported with ElementTree.write()")

            parser = self.etree.XMLParser(attribute_defaults=True, collect_ids=False)
            tree = self.etree.parse(input_file, parser)
            out = io.BytesIO()
            tree.write(
                out, method='c14n2',
                with_comments=with_comments, strip_text=strip_text,
                **options)
            return out.getvalue().decode('utf8')

    class ETreeC14N2TostringTest(ETreeC14NTest):
        def _canonicalize(self, input_file, with_comments=True, strip_text=False,
                          rewrite_prefixes=False, qname_aware_tags=None, qname_aware_attrs=None,
                          **options):
            if rewrite_prefixes or qname_aware_attrs or qname_aware_tags:
                self.skipTest("C14N 2.0 feature not supported with ElementTree.tostring()")

            parser = self.etree.XMLParser(attribute_defaults=True, collect_ids=False)
            tree = self.etree.parse(input_file, parser)
            return self.etree.tostring(
                tree, method='c14n2',
                with_comments=with_comments, strip_text=strip_text,
                **options).decode('utf8')


if ElementTree:
    class ElementTreeTestCase(_ETreeTestCaseBase):
        etree = ElementTree

        @classmethod
        def setUpClass(cls):
            if sys.version_info >= (3, 9):
                return
            import warnings
            # ElementTree warns about getiterator() in recent Pythons
            warnings.filterwarnings(
                'ignore',
                r'This method will be removed.*\.iter\(\).*instead',
                PendingDeprecationWarning)

    filter_by_version(
        ElementTreeTestCase,
        ElementTreeTestCase.required_versions_ET, ET_VERSION)

    if hasattr(ElementTree, 'XMLPullParser'):
        class ElementTreePullTestCase(_XMLPullParserTest):
            etree = ElementTree
    else:
        ElementTreePullTestCase = None

    if hasattr(ElementTree, 'canonicalize'):
        class ElementTreeC14NTest(_C14NTest):
            etree = ElementTree
    else:
        ElementTreeC14NTest = None

    class ElementTreeElementSlicingTest(_ElementSlicingTest):
        etree = ElementTree


if cElementTree:
    class CElementTreeTestCase(_ETreeTestCaseBase):
        etree = cElementTree

    filter_by_version(
        CElementTreeTestCase,
        CElementTreeTestCase.required_versions_cET, CET_VERSION)

    class CElementTreeElementSlicingTest(_ElementSlicingTest):
        etree = cElementTree


def test_suite():
    suite = unittest.TestSuite()
    if etree:
        suite.addTests([unittest.defaultTestLoader.loadTestsFromTestCase(ETreeTestCase)])
        suite.addTests([unittest.defaultTestLoader.loadTestsFromTestCase(ETreePullTestCase)])
        suite.addTests([unittest.defaultTestLoader.loadTestsFromTestCase(ETreeElementSlicingTest)])
        suite.addTests([unittest.defaultTestLoader.loadTestsFromTestCase(ETreeC14NTest)])
        suite.addTests([unittest.defaultTestLoader.loadTestsFromTestCase(ETreeC14N2WriteTest)])
        suite.addTests([unittest.defaultTestLoader.loadTestsFromTestCase(ETreeC14N2TostringTest)])
    if ElementTree:
        suite.addTests([unittest.defaultTestLoader.loadTestsFromTestCase(ElementTreeTestCase)])
        if ElementTreePullTestCase:
            suite.addTests([unittest.defaultTestLoader.loadTestsFromTestCase(ElementTreePullTestCase)])
        if ElementTreeC14NTest:
            suite.addTests([unittest.defaultTestLoader.loadTestsFromTestCase(ElementTreeC14NTest)])
        suite.addTests([unittest.defaultTestLoader.loadTestsFromTestCase(ElementTreeElementSlicingTest)])
    if cElementTree:
        suite.addTests([unittest.defaultTestLoader.loadTestsFromTestCase(CElementTreeTestCase)])
        suite.addTests([unittest.defaultTestLoader.loadTestsFromTestCase(CElementTreeElementSlicingTest)])
    return suite

if __name__ == '__main__':
    print('to test use test.py %s' % __file__)