Negative rerun counts can skip tests with exit code 0

[janmrow]

It looks like a negative rerun count can cause a collected test not to run, while pytest exits successfully.

For example, running pytest --reruns=-1 with:

def test_should_run():
    assert False

collects one test, but does not report a test result and exits with code 0.

The same happens with negative values from:

• reruns = -1
• @pytest.mark.flaky(reruns=-1)
• --force-reruns=-1

--reruns=0 works as expected here.

Negative rerun counts should probably be rejected as invalid configuration instead of allowing the test session to succeed without running the test.
If this looks worth fixing, I'd be happy to work on it.