give some context that could help the user when the tool cannot find the failing tests

[zsoldosp]

When trying to debug a flaky test, I got the following output

$ detect-test-pollution  --failing-test ...  --tests ...
discovering all tests...
-> discovered 83 tests!
ensuring test passes by itself...
-> OK!
ensuring test fails with test group...
-> OK!
running step 1:
- 82 tests remaining (about 7 steps)
running step 2:
- 41 tests remaining (about 6 steps)
running step 3:
- 21 tests remaining (about 5 steps)
running step 4:
- 11 tests remaining (about 4 steps)
running step 5:
- 6 tests remaining (about 3 steps)
running step 6:
- 3 tests remaining (about 2 steps)
running step 7:
- 2 tests remaining (about 1 steps)
double checking we found it...
Traceback (most recent call last):
  File "/usr/local/bin/detect-test-pollution", line 8, in <module>
    sys.exit(main())
  File "/usr/local/lib/python3.9/site-packages/detect_test_pollution.py", line 289, in main
    return _bisect(testpath, args.failing_test, testids)
  File "/usr/local/lib/python3.9/site-packages/detect_test_pollution.py", line 241, in _bisect
    raise AssertionError('unreachable? unexpected pass? report a bug?')
AssertionError: unreachable? unexpected pass? report a bug?

at this point, I cannot tell which tests were considered and I'm not any smarter about the test pollution than I have been before using the tool

I've tried passing options to pytest using PYTEST_ADDOPTS (PYTEST_ADDOPTS="-vvv" detect-test-pollution --failing-test ... --tests ...), but that didn't help.

I recall having pollution only when 3 tests were run in a given order in the past, so it is a totally fine if the tool cannot find it, but should help the user still

Some solution ideas that come to mind would be

• upon not being able to narrow it down to one, list the last set of testids with which the test failed
• display the output from the test run combined with allow the user passing options to the testrunner being invoked (e.g.: -vvv to pytest)
• have a --verbose flag (or -vvvv style) and under the "<N> tests remaining (about <X> steps)" message print out the testids considered

but of course there might be other alternatives I haven't considered