All tests are run when only last failed tests are requested

[arnaudsjs]

Observed behavior:

When I run pytest -s --lf --lfnf=none tests and all the tests that failed during the previous run of the test suite where removed, all the tests are run.

Expected behavior:

I would expect that no tests are run at all in the above-mentioned situation, because the user explicitly requested to only run the tests that failed previously. Given that there are none, no tests should run.

Minimal reproduction:

Step 1: Run pytest tests with the following tests/test_test.py file:

def test_test1():
    raise Exception()
 
def test_test2():
    return

This produces the following output:

Test session starts (platform: linux, Python 3.12.11, pytest 8.4.1, pytest-sugar 1.0.0)
Using --randomly-seed=533107519
rootdir: /tmp/test
configfile: pyproject.toml
plugins: time-machine-2.16.0, env-1.1.5, cov-6.2.1, instafail-0.5.0, sugar-1.0.0, timeout-2.4.0, randomly-3.16.0, postgresql-7.0.2, asyncio-1.1.0, logfire-4.0.0
asyncio: mode=Mode.AUTO, asyncio_default_fixture_loop_scope=None, asyncio_default_test_loop_scope=function
collected 2 items                                                                                                                                                     


――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――― test_test1 ――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――

    def test_test1():
>       raise Exception()
E       Exception

tests/test_test.py:2: Exception

 tests/test_test.py ⨯✓                                                                                                                                  100% ██████████
======================================================================= short test summary info =======================================================================
FAILED tests/test_test.py::test_test1 - Exception

Results (0.06s):
       1 passed
       1 failed
         - tests/test_test.py:1 test_test1

Step 2: Run pytest --lf --lfnf=none tests with the following tests/test_test.py file (remove test1):

def test_test2():
    return

This produces the following output:

Test session starts (platform: linux, Python 3.12.11, pytest 8.4.1, pytest-sugar 1.0.0)
Using --randomly-seed=304109397
rootdir: /tmp/test
configfile: pyproject.toml
plugins: time-machine-2.16.0, env-1.1.5, cov-6.2.1, instafail-0.5.0, sugar-1.0.0, timeout-2.4.0, randomly-3.16.0, postgresql-7.0.2, asyncio-1.1.0, logfire-4.0.0
asyncio: mode=Mode.AUTO, asyncio_default_fixture_loop_scope=None, asyncio_default_test_loop_scope=function
collected 1 item                                                                                                                                                      
run-last-failure: 1 known failures not in selected tests

 tests/test_test.py ✓                                                                                                                                   100% ██████████

Results (0.02s):
       1 passed

Software versions:

• The above-mentioned issue happens on pytest==8.4.1

[RonnyPfannschmidt]

this is a specific edge case that requires discussion - even when running a partial testsuite, lastfailed needs to run all requested tests if all failures within the requested tests have been resolved

by deleting the tests, thus cutting the "requested test set" it now needs to run all tests as no longer failures are visible in the collectable requested tests

[The-Compiler]

lastfailed needs to run all requested tests if all failures within the requested tests have been resolved

Isn't it the intention behind --lfnf=none (as used by OP) to prevent that?

--lfnf, --last-failed-no-failures={all,none}

With --lf, determines whether to execute tests when there are no previously (known) failures or when no cached lastfailed data was found. all (the default) runs the full test suite again. none just emits a message about no known failures and exits successfully.

[RonnyPfannschmidt]

Im under the impression lfnf is not correctly integrated

Plus selection seems to be based on paths

Non existent paths aren't considered