PHPUnit (on PHP, of course).
But I never managed to get it working inside Komodo. It looks like Komodo's approach is still the one used in the pre-composer era, when everyone were using a single, system-wide installation of PHPUnit.
Nowadays, everyone runs PHPUnit from a local, project-wide installation, e.g. from vendor directory (unless differently specified in composer.json, for example I like to set "bin-dir": "bin", like many others)