pytest: How to get a list of all failed tests at the end of the session? (and while using xdist)

Question

I would like to have a list of all the tests that have failed to be used at the end of session.

Pytest lets you define a hook pytest_sessionfinish(session, exitstatus), that is called at the end of the session, where I wish to have that list.

session is a _pytest.main.Session instance that has the attribute items (type list), but I couldn't find whether the each item in that list passed of failed.

1. How can a list of all failed tests could be retrieved at the end of the session?

2. How can it be done while using pytest-xdist plugin, where I would like to get that list in the master process. Using this plugin, session does not even have items attribute in the master:

   def pytest_sessionfinish(session, exitstatus):
       if os.environ.get("PYTEST_XDIST_WORKER", "master") == "master":
            print(hasattr(session, "items"))  # False
   

Answer 1

Run pytest with -rf to get it to print a list of failed tests at the end.

From py.test --help:

  -r chars              show extra test summary info as specified by chars
                        (f)ailed, (E)error, (s)skipped, (x)failed, (X)passed,
                        (p)passed, (P)passed with output, (a)all except pP.
                        Warnings are displayed at all times except when
                        --disable-warnings is set

Here's what you get:

$ py.test -rf
================= test session starts =================
platform darwin -- Python 3.7.2, pytest-4.3.1, py-1.6.0, pluggy-0.7.1
[...]
=============== short test summary info ===============
FAILED test_foo.py::test_foo_is_flar
FAILED test_spam.py::test_spam_is_mostly_pork
FAILED test_eggs.py::test_eggs_are_also_spam
=== 3 failed, 222 passed, 8 warnings in 12.52 seconds ==

Answer 2

If you want results of the tests you can use hook runtest_makereport:

@pytest.hookimpl(tryfirst=True, hookwrapper=True)
def pytest_runtest_makereport(item, call):
    outcome = yield
    rep = outcome.get_result()
    if rep.when == 'call' and rep.failed:
        mode = 'a' if os.path.exists('failures') else 'w'
        try:  # Just to not crash py.test reporting
          pass  # the test 'item' failed
        except Exception as e:
            pass