support --last-failed AND other tests collected together

From what I gather this is not currently supported, infact it seems to just deselect all of the tests?

import pytest


@pytest.mark.only
def test_one():
    pass


def test_two():
    raise Exception('no')

pytest

creates:

│   .gitignore
│   CACHEDIR.TAG
│   README.md
│
└───v
    └───cache
            lastfailed
            nodeids
            stepwise

sy@sy-PC MINGW64 ~/PycharmProjects/untitled2/.pytest_cache/v/cache
$ cat lastfailed
{
  "test_it.py::test_two": true
}

ideally i would like to run --last-failed and also specify some sort of marker / keyword expr, to collect other tests in with the failure(s) like so:

pytest --last-failed -m only

what this actually does is deselect both tests

========================================================================================================= test session starts =========================================================================================================
platform win32 -- Python 3.7.3, pytest-5.3.5, py-1.8.1, pluggy-0.13.1
rootdir: C:\Users\sy\PycharmProjects\untitled2
plugins: cov-2.8.1, forked-1.1.3, infrastructure-0.0.1, xdist-1.31.0
collected 2 items / 2 deselected                                                                                                                                                                                                       
run-last-failure: rerun previous 1 failure

[bluetech]

The word “and” has a confusing double meaning in English and in programming 😄

Currently, pytest filters, such as --last-failed, -m and -k, are ANDed together in the logic sense. That is they apply on top of each other. Or in words, “collect test if matches last-failed AND matches -m AND matches -k”.

I think @symonk is requesting to be able to OR them instead of AND. In words, “collect test if matches last-failed OR matches -m”. pytest currently doesn’t support this.

Some other command line programs have schemes to handle similar situations, in particular the find UNIX command comes to mind. For example, find -name myfile -or -empty matches files whose name is “myfile” OR files which are empty. If the -or is omitted the default is AND.

Interestingly, pytest does allow such expressions inside -m and -k, for example -m "(foo and bar) or baz". So one avenue to add this ability to pytest might be to combine -m and -k as well as --last-failed and command line paths and all other such into one unified “filter expression” which supports and/or/not/parenthesis syntax. But that’s just an idea that would require some design work 😃

[joaonc]

Wouldn’t that invalidate the scenarios where using --last-failed -m only is supposed to run only the tests that (failed + have only mark)? Ie, tests that have that mark but didn’t fail, should not run.

IMO, the scenario “as a test writer i do not want last failed to deselect tests with a special marker even if the passed before” should not be possible with one command line and rather use 2 different command lines:

pytest <tests> --last-failed
pytest  <tests> -m only

Potentially combine the results later.