`capsys`

By default, pytest runs with output capturing enabled (to keep test results clean), meaning:

print() output does not appear on the terminal.
pytest captures both stdout and stderr internally.
failed tests show the captured output in the traceback.

The capsys fixture lets you read captured output during a test:

python

def test_output_capture(capsys):
    print("hello world")

    out, err = capsys.readouterr()
    assert out.strip() == "hello world"
    assert err == ""

You can temporarily disable capture for a block of code::

python

with capsys.disabled():
    print("This will be shown immediately.")

WARNING

When pytest is run with the -s option, all output capturing is disabled. As a result, capsys.readouterr() will always return empty strings for both stdout and stderr, and capsys.disabled() has no additional effect since capturing is already turned off.

capsys ​

`capsys`