Add test for desired float_to_top behavior

tests/unit/test_regressions.py

@@ -714,3 +714,171 @@ def test_isort_doesnt_mangle_code_when_adding_imports_issue_1444():
 import os
 '''
     )
+
+
+def test_isort_doesnt_float_to_top_correctly_when_imports_not_at_top_issue_1382():
+    """isort should float existing imports to the top, if they are currently below the top.
+    See: https://github.com/PyCQA/isort/issues/1382
+    """
+    assert isort.code('''
+def foo():
+    pass
+
+import a
+
+def bar():
+    pass
+''',
+    float_to_top=True) == '''import a
+
+
+def foo():
+    pass
+
+
+def bar():
+    pass
+'''
+
+    assert isort.code('''
+
+
+
+
+
+
+def foo():
+    pass
+
+import a
+
+def bar():
+    pass
+''',
+    float_to_top=True) == '''import a
+
+
+def foo():
+    pass
+
+
+def bar():
+    pass
+'''
+
+    assert isort.code('''"""My comment
+
+
+"""
+def foo():
+    pass
+
+import a
+
+def bar():
+    pass
+''',
+    float_to_top=True) == '''"""My comment
+
+
+"""
+import a
+
+
+def foo():
+    pass
+
+
+def bar():
+    pass
+'''
+
+
+    assert isort.code('''
+"""My comment
+
+
+"""
+def foo():
+    pass
+
+import a
+
+def bar():
+    pass
+''',
+    float_to_top=True) == '''
+"""My comment
+
+
+"""
+import a
+
+
+def foo():
+    pass
+
+
+def bar():
+    pass
+'''
+
+    assert isort.code('''#!/bin/bash
+"""My comment
+
+
+"""
+def foo():
+    pass
+
+import a
+
+def bar():
+    pass
+''',
+    float_to_top=True) == '''#!/bin/bash
+"""My comment
+
+
+"""
+import a
+
+
+def foo():
+    pass
+
+
+def bar():
+    pass
+'''
+
+    assert isort.code('''#!/bin/bash
+
+"""My comment
+
+
+"""
+def foo():
+    pass
+
+import a
+
+def bar():
+    pass
+''',
+    float_to_top=True) == '''#!/bin/bash
+
+"""My comment
+
+
+"""
+import a
+
+
+def foo():
+    pass
+
+
+def bar():
+    pass
+'''