fixture teardown sequence

[ws1088]

Hi all,
It looks like a function scope fixture is torn down after the printing of . in the console. I am writing a fixture which capture stdout/stderr to a file and it is capturing �[32m.�[0m before print('hello'):

@pytest.fixture
def my_fixture(request: FixtureRequest):
    # setup capturing of stdout/stderr to a test-specific file
    # ...
    yield 'something'
    print('hello')
    # restore stdout/stderr
    # ...

test-specific file content:

�[32m.�[0mhello

Am I doing anything wrong?
Thanks in advance.

[portyu9]

Hi @ws1088

What you are seeing is consistent with pytest's execution order.

With a yield fixture:

setup
yield
teardown

pytest runs the test call after the yield, generates/reports the test-call result, and only then resumes fixture teardown.

So if your fixture redirects the process's stdout/file descriptor across the entire yield, pytest's own progress output such as:

.

can be written while that redirection is still active. By the time the fixture restores stdout in teardown, the progress character has already gone to your file.

The fix is not to hold a global stdout/stderr redirection open across the entire pytest test lifecycle.

Prefer one of:

• pytest's capsys / capfd fixtures for captured output;
• an application-specific output stream;
• a logging FileHandler;
• a narrowly scoped redirect around only the application call that needs it.

A fixture finalizer cannot restore the descriptor before pytest reports the test call because teardown happens afterward.

Please mark this answer as accepted if it helped, thank you.