It just times out. Let's update our grunt/Makefile command to use the same as core.
|Resolved||Jhernandez||T104318 [GOAL]: Testing practices & expose test coverage|
|Open||None||T100294 [EPIC] Encourage developers to increase code coverage|
|Declined||Jdlrobson||T103440 Write tests for modules that are in stable and have low code coverage|
|Declined||Jdlrobson||T112568 `grunt qunit` tool no longer works|
Rather than using the same as core I propose it is simply removed. Similar to the PHPUnit entry point, extensions are not meant to create their own QUnit context because the needed information exists only in core.
MediaWiki core already has working entry points for phpunit and qunit. I suggest you use those instead. They include any registered extensions' test suites, and the current code in Gather and MobileFrontend already makes use of that, so nothing would change, except the directory from which you run the grunt qunit command.