how to identify the test harness in use

[XSven]

I wanted to check in my test script which test harness is in use. I would like to distinguish Test::Harness (ExtUtils::MakeMaker manged test) and TAP::Harness (prove managed test). How can I do this? I have checked the environment (HARNESS_* environment variables) without success.

[Leont]

Test::Harness is just a wrapper for TAP::Harness, and has been for about 20 years, so I don't know why you would want to make such a distinction.

[XSven]

I know that because I have sufficiently careful read the documentation. Time (20 years) could mean something but it doesn't have to. My use case:

I have written a new App::Prove plugin. My build system (install tool in your terminology) is ExtUtils::MakeMaker. I have written a unit test script that requires the plugin and calls its load() method. I would like to add an integration test script that by definition should be run through prove using its -P option. The former unit test script shouldn't be deselected but should skip_all if prove is executing it. That's why I want to check the harness in my unit test script.

All kinds of harness related information is passed to test scripts using HARNESS_* environment variables but the most obvious/trivial information the harness package name is not part of this information.