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pytest capsys not caputuring output

See original GitHub issue

Hey,

according to the docs I was expecting the default logger to write to stderr:

you can use the Logger right after import as it comes pre-configured (logs are emitted to sys.stderr by default)

So I was running this minimal example with pytest and was expecting it to work:

from loguru import logger


def test_logger(capsys):
    logger.error("Some Error")
    out, err = capsys.readouterr()
    assert "Some Error" in err

However it fails. When I add an explicit Handler that writed to stderr, it works. Why does the default handler not work?

Issue Analytics

State:
Created a year ago
Comments:5 (3 by maintainers)

Top GitHub Comments

1reaction

Delgancommented, Sep 18, 2022

Hi.

This is not working out of the box with capsys due to Pytest internals which replace sys.stderr with their own special object. Consequently, if logger.add() was called prior to the running the test, the Loguru’s handler is lost.

0reactions

elisiariocoutocommented, Nov 8, 2022

Sure, will do. Thanks

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