Unable to log/capture pytest header in a file

[tilusnet]

pytest is nicely outputting a header like

==================================================================================== test session starts =====================================================================================
platform linux -- Python 3.9.13, pytest-7.1.2, pluggy-1.0.0
rootdir: ..., configfile: pytest.ini
plugins: timeout-2.1.0, cov-2.12.1

<header ends>
collected 5 items 
....

I find it impossible to get this header into a file.

pytest 2>&1 > my_file.txt doesn't work either.
Why?

[nicoddemus]

Hi @tilusnet,

Can't reproduce this on Windows:

λ pytest .tmp\test_foo.py 2>&1 > out.txt
λ cat out.txt
======================== test session starts ========================
platform win32 -- Python 3.9.8, pytest-7.2.0.dev91+g1689b3886.d20220613, pluggy-1.0.0
rootdir: e:\projects\pytest\.tmp, configfile: pytest.ini
plugins: hypothesis-6.34.1, flake8-1.0.7, flakes-4.0.5
collected 1 item

.tmp\test_foo.py .                                             [100%]

========================= 1 passed in 0.00s =========================

Also not sure why this wouldn't work on Linux... 🤔

[tilusnet]

It seems, it has to do with a pytest.ini present.
But what affects it?:

log_cli = 1
log_cli_level = INFO

markers =
    integration: mark a test as an integration test
    snapshot: mark a test as a snapshot test
log_level = WARNING

[tilusnet]

Where on earth is the header written if neither stdout nor stderr can capture it?
I see the header on the screen!

[nicoddemus]

I get the same results even with a pytest.ini with those contents... definitely something weird going on.

Can you go to another directory (outside the project you are working on), create a new virtual environment, install pytest, run the command, and check if it gets redirected to a file? I suggest that to try to isolate if this is related to your current environment or the test suite you are trying to execute.