GenerateMochaConfig is a MediaWiki maintenance extension that generates a JSON that can be used to run Mocha tests for all enabled extensions with a tests/mocha directory.
To enable it, first download a copy of the GenerateMochaConfig directory and put it into your extensions directory. Then put the following at the end of your LocalSettings.php:
wfLoadExtension ( 'GenerateMochaConfig' );
To get a Mocha configuration JSON for all enabled extensions run:
$ php extensions/GenerateMochaConfig/maintenance/generateMochaConfig.php
To merge the Mocha configuration JSON with an existing mocharc.json file run:
$ php extensions/GenerateMochaConfig/maintenance/generateMochaConfig.php --config <filename>