Manual:JavaScript unit testing

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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 tests[edit]

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

In a browser[edit]

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 line[edit]

Use npm install && grunt 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 committing[edit]

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

Write unit tests[edit]

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[edit]

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[edit]

MediaWiki core[edit]

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.foobar.test.js',
 	'dependencies' => array(
+		'mediawiki.foobar',


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

See also[edit]