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Manual:JavaScript unit testing

MediaWiki's QUnit test suite running in Chrome.

MediaWiki uses QUnit to unit test its JavaScript code base.

The unit tests for MediaWiki core are located in the tests/qunit/suites directory[1].


Run the testsEdit

Ensure $wgEnableJavaScriptTest is set to true in your LocalSettings.php file.

In a browserEdit

Open Special:JavaScriptTest in a browser to run the tests.


Check for Globals
Core URL parameter of QUnit.[2]
No try-catch
Core URL parameter of QUnit.[2]
Enable ResourceLoaderDebug
Toggle ResourceLoader debug mode.
Select a module from the list to immediately run it.[3]

From the command lineEdit

Use npm install && npm run qunit from the MediaWiki core directory to run QUnit tests from the command-line in Chrome and aggregate the results.

How to help?Edit

Run tests before committingEdit

Make it a habit to run unit tests before committing and submitting your changes to Gerrit.

Write unit testsEdit

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 testEdit

It is the convention to name the test suite file after the module it covers. For example, 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.

Register a testEdit

MediaWiki coreEdit

Test suites are added to the registration of the mediawiki.tests.qunit.suites module in /tests/qunit/QUnitTestResources.php.

Tests are organised into a directory structure that matches the directory structure of the code being tested. For example: The unit test for resources/mediawiki.util/mediawiki.util.js can be found at tests/qunit/suites/resources/mediawiki.util/mediawiki.util.test.js.


 'mediawiki.tests.qunit.suites' => array(
 	'scripts' => array(
+		'tests/qunit/suites/resources/mediawiki/mediawiki.example.test.js',
 	'dependencies' => array(
+		'mediawiki.example',


Extensions register their QUnit tests via the ResourceLoaderTestModules hook.

See alsoEdit