Manual:JavaScript unit testing

Unit testing in MediaWiki for its JavaScript code base is performed using the QUnit JavaScript Testing framework..

The unit tests in core are located in the tests/qunit directory. Tests are organised into a directory structure that matches the directory structure of the code that they are testing. For example: The unit tests for file resources/mediawiki.util/mediawiki.util.js can be found in tests/qunit/suites/resources/mediawiki.util/mediawiki.util.test.js.

Extensions add their QUnit tests on the ResourceLoaderTestModules hook.

§Run the tests

If all goes well, the tests will quickly run and show a green bar at the top like this.

Make sure $wgEnableJavaScriptTest is set to true.

§In a browser

Unit tests are run using a special page.

Open Special:JavaScriptTest/qunit/plain in any browser to run the tests.

Options:

Check for Globals

Core URL parameter of QUnit.

No try-catch

Core URL parameter of QUnit.

Enable ResourceLoaderDebug

Toggle ResourceLoader debug mode.

mwlogenv

When enabled, setup and teardown of QUnit.newMwEnvironment will be logged to the console.

Module

Select a module from the list to immediately run it.

§From the command line

Use npm install && grunt qunit from the MediaWiki core directory to run QUnit tests from the command-line in you local Chrome browser.

§How to help?

§Run tests before committing

Make it a habit to run unit tests before committing and submitting your changes to Gerrit. Any problems that you didn't cause? See if you can find a cause and let the committer know by leaving a comment in Gerrit.

§Write unit tests

Always write unit tests for new functionality. We're also looking to expand our unit test coverage of already existing modules in the MediaWiki JavaScript library.

§Write a unit test

TODO: Incomplete

• The file should be named after the module (or file) it is testing. E.g. mediawiki.user.test.js covers the mediawiki.user module.

• Inside the test suite should be one, and only one, call to QUnit.module with the module name.

§How to register a test suite

§MediaWiki core

Core test suites need to be added to the registration of the mediawiki.tests.qunit.suites module. Do so in /tests/qunit/QUnitTestResources.php.

If you created a test suite for mediawiki.foobar, then that test suite should be in /tests/qunit/suites/resources/mediawiki/mediawiki.foobar.test, and add that file path to the "scripts" array. Ensure the mediawiki.foobar module is listed as a dependency (as that module must be loaded before the test suite).

 'mediawiki.tests.qunit.suites' => array(
 	'scripts' => array(
 		'tests/qunit/suites/resources/mediawiki/mediawiki.test.js',
+		'tests/qunit/suites/resources/mediawiki/mediawiki.foobar.test.js',
 		'tests/qunit/suites/resources/mediawiki/mediawiki.user.test.js',
 		'tests/qunit/suites/resources/mediawiki/mediawiki.util.test.js',
 	),
 	'dependencies' => array(
 		'mediawiki',
+		'mediawiki.foobar',
 		'mediawiki.user',
 		'mediawiki.util',

§Extensions

Extensions register their tests suites as a module. See Manual:Hooks/ResourceLoaderTestModules for more details.

§Tips

• The tests should work in all language environments, but sometimes may fail if $wgLanguageCode is not "en". If your wiki's language is not "en" and tests fail mysteriously, try changing $wgLanguageCode to "en" and running the tests, and then try with your language again.

§See also

• Manual:Writing testable JavaScript
• Manual:Hooks/ResourceLoaderTestModules
• Manual:JavaScript unit testing/QUnit guidelines