For future reference if you use an alternative configuration file in PHPStorm for your PHPUnit Run/Debug config it doesn't get applied to ad-hoc method tests unless you set the "Default configuation file" property under "Test Runner" in the "Test Frameworks" config pane.

If this helps just one other from wasting a morning figuring out why their tests run as a batch but not when filtered as a singular it will have been worth documenting. #php