human
I wrote the below code

    p = testdir.makepyfile('\n                                import    pytest\n                                @pytest.fixture\n                                def    arg():\n                                                assert    False\n                                def    test_arg(arg):\n                                                assert    False\n                ')
    result = testdir.runpytest('--setup-plan', p)
    assert (result.ret == 0)
    result.stdout.fnmatch_lines(['*SETUP                F    arg*', '*test_arg    (fixtures    used:    arg)', '*TEARDOWN    F    arg*'])

What's a good function header?
 Here's a good function header?
assistant
#Here's a good function header.

def test_show_fixtures_and_test(testdir):