Implement helper for our ESLint plugin

eslint-plugin-helper.js

@@ -0,0 +1,37 @@
+'use strict';
+const babelPipeline = require('./lib/babel-pipeline');
+const normalizeExtensions = require('./lib/extensions');
+const {hasExtension, normalizeGlobs, classify} = require('./lib/globs');
+const loadConfig = require('./lib/load-config');
+
+const cache = new Map();
+
+function load(projectDir) {
+	if (cache.has(projectDir)) {
+		return cache.get(projectDir);
+	}
+
+	const conf = loadConfig(projectDir);
+	const babelConfig = babelPipeline.validate(conf.babel);
+	const extensions = normalizeExtensions(conf.extensions || [], babelConfig);
+	const globs = {cwd: projectDir, ...normalizeGlobs(conf.files, conf.helpers, conf.sources, extensions.all)};
+
+	const helper = Object.freeze({
+		classifyFile: file => classify(file, globs),
+		classifyImport: importPath => {
+			if (hasExtension(globs.extensions, importPath)) {
+				// The importPath has one of the test file extensions: we can classify
+				// it directly.
+				return classify(importPath, globs);
+			}
+
+			// Add the first extension. If multiple extensions are available, assume
+			// patterns are not biased to any particular extension.
+			return classify(`${importPath}.${globs.extensions[0]}`, globs);
+		}
+	});
+	cache.set(projectDir, helper);
+	return helper;
+}
+
+exports.load = load;

lib/globs.js

@@ -92,6 +92,8 @@ exports.normalizeGlobs = normalizeGlobs;
 
 const hasExtension = (extensions, file) => extensions.includes(path.extname(file).slice(1));
 
+exports.hasExtension = hasExtension;
+
 const findFiles = async (cwd, patterns) => {
 	const files = await globby(patterns, {
 		absolute: true,

lib/load-config.js

@@ -7,10 +7,10 @@ const pkgConf = require('pkg-conf');
 const NO_SUCH_FILE = Symbol('no ava.config.js file');
 const MISSING_DEFAULT_EXPORT = Symbol('missing default export');
 
-function loadConfig(defaults = {}) {
-	const packageConf = pkgConf.sync('ava');
+function loadConfig(resolveFrom = process.cwd(), defaults = {}) {
+	const packageConf = pkgConf.sync('ava', {cwd: resolveFrom});
 	const filepath = pkgConf.filepath(packageConf);
-	const projectDir = filepath === null ? process.cwd() : path.dirname(filepath);
+	const projectDir = filepath === null ? resolveFrom : path.dirname(filepath);
 
 	let fileConf;
 	try {

profile.js

@@ -32,7 +32,7 @@ function resolveModules(modules) {
 
 Promise.longStackTraces();
 
-const conf = loadConfig({
+const conf = loadConfig(undefined, {
 	babel: {
 		testOptions: {}
 	},

test/eslint-plugin-helper.js

@@ -0,0 +1,94 @@
+'use strict';
+const path = require('path');
+const {test} = require('tap');
+
+const {load} = require('../eslint-plugin-helper');
+
+const projectDir = path.join(__dirname, 'fixture/eslint-plugin-helper');
+
+test('caches loaded configuration', t => {
+	const expected = load(projectDir);
+	const actual = load(projectDir);
+	t.is(expected, actual);
+	t.end();
+});
+
+test('classifies files according to the configuration', t => {
+	const helper = load(projectDir);
+	t.deepEqual(helper.classifyFile(path.join(projectDir, 'tests/test.foo')), {
+		isHelper: false,
+		isSource: false,
+		isTest: true
+	});
+	t.deepEqual(helper.classifyFile(path.join(projectDir, 'tests/_helper.foo')), {
+		isHelper: true,
+		isSource: false,
+		isTest: false
+	});
+	t.deepEqual(helper.classifyFile(path.join(projectDir, 'helpers/helper.foo')), {
+		isHelper: true,
+		isSource: false,
+		isTest: false
+	});
+	t.deepEqual(helper.classifyFile(path.join(projectDir, 'source.foo')), {
+		isHelper: false,
+		isSource: true,
+		isTest: false
+	});
+	t.deepEqual(helper.classifyFile(path.join(projectDir, 'tests/test.js')), {
+		isHelper: false,
+		isSource: false,
+		isTest: false
+	});
+	t.end();
+});
+
+test('classifies imports with extension according to the configuration', t => {
+	const helper = load(projectDir);
+	t.deepEqual(helper.classifyImport(path.join(projectDir, 'tests/test.foo')), {
+		isHelper: false,
+		isSource: false,
+		isTest: true
+	});
+	t.deepEqual(helper.classifyImport(path.join(projectDir, 'tests/_helper.foo')), {
+		isHelper: true,
+		isSource: false,
+		isTest: false
+	});
+	t.deepEqual(helper.classifyImport(path.join(projectDir, 'helpers/helper.foo')), {
+		isHelper: true,
+		isSource: false,
+		isTest: false
+	});
+	t.deepEqual(helper.classifyImport(path.join(projectDir, 'source.foo')), {
+		isHelper: false,
+		isSource: true,
+		isTest: false
+	});
+	t.end();
+});
+
+test('classifies imports without extension according to the configuration', t => {
+	const helper = load(projectDir);
+	t.deepEqual(helper.classifyImport(path.join(projectDir, 'tests/test')), {
+		isHelper: false,
+		isSource: false,
+		isTest: true
+	});
+	t.deepEqual(helper.classifyImport(path.join(projectDir, 'tests/_helper')), {
+		isHelper: true,
+		isSource: false,
+		isTest: false
+	});
+	t.deepEqual(helper.classifyImport(path.join(projectDir, 'helpers/helper')), {
+		isHelper: true,
+		isSource: false,
+		isTest: false
+	});
+	t.deepEqual(helper.classifyImport(path.join(projectDir, 'source')), {
+		isHelper: false,
+		isSource: true,
+		isTest: false
+	});
+	t.end();
+});

test/fixture/eslint-plugin-helper/ava.config.js

@@ -0,0 +1,6 @@
+export default {
+	babel: false,
+	files: ['tests/**/*'],
+	helpers: ['helpers/*'],
+	extensions: ['foo']
+};

test/fixture/eslint-plugin-helper/package.json

@@ -0,0 +1 @@
+{}

test/load-config.js

@@ -21,6 +21,13 @@ test('finds config in package.json', t => {
 	t.end();
 });
 
+test('loads config from a particular directory', t => {
+	changeDir('throws');
+	const conf = loadConfig(path.resolve(__dirname, 'fixture', 'load-config', 'package-only'));
+	t.is(conf.failFast, true);
+	t.end();
+});
+
 test('throws a warning of both configs are present', t => {
 	changeDir('package-yes-file-yes');
 	t.throws(loadConfig);
@@ -32,7 +39,7 @@ test('merges in defaults passed with initial call', t => {
 	const defaults = {
 		files: ['123', '!456']
 	};
-	const {files, failFast} = loadConfig(defaults);
+	const {files, failFast} = loadConfig(undefined, defaults);
 	t.is(failFast, true, 'preserves original props');
 	t.is(files, defaults.files, 'merges in extra props');
 	t.end();