How to add a fixture from pytest_generate_tests?

[amitw-di]

Hi,
I tried to add a fixture inside pytest_generate_tests, and while I've been able to add something, the fixture code is not working.

example of my attempt:

   def pytest_generate_tests(self, metafunc):
        marks = metafunc.definition.iter_markers('use_myfix')
        if len(list(marks)) > 0 and myOS == 'Windows':
            metafunc.fixturenames.append('myfix')
            metafunc.parametrize('myfix', ['myfix-1', 'myfix-2', 'myfix-3'], indirect=True)

The test, naturally, is not aware of the "myfix" parameter, and I want to have this similar to an autouse fixture (only for the relevant test).

I have seen the question here:#10686, but at least since this PR: #11209, the answer there is not possible. Even after trying to copy the FuncFixtureInfo object, code isn't being executed.
I also tried the workaround suggested there with a wrapper fixture, only it seems that the args added in pytest_generate_tests are not being added to the ones in request (which is quite odd).

Any ideas?

[RonnyPfannschmidt]

alering fixturenames has no safe effect - please add a usefixtures marker to the metafunc.definition node

[amitw-di]

Thanks for the answer, I'm probably doing something wrong, since this seems to have no effect.

    metafunc.definition.own_markers.append(pytest.mark.usefixtures('myfix'))
    # metafunc.definition.fixturenames.append('myfix')
    metafunc.parametrize('myfix', ['myfix-1', 'myfix-2', 'myfix-3'], indirect=True)

Without the commented out line, I'm getting "function uses no fixture 'myfix' "

With the commented out line stuff run, but the fixture's code is not being invoked.

what am I missing?

[RonnyPfannschmidt]

this is possibly a interaction bug - mast likely related to when/how fixturenames is set up

we need to open a issue on this (as its not something i myself can work on soonish)