[lang-ref] ( capture_stdout_and_stderr ) ( python )

def test_capture_stdout_and_stderr(capsys):
    # capsys
    # This is pytest's 'capsys' fixture.
    import sys
    print('[INFO] Hello')
    print('[ERROR] Oops..', file=sys.stderr)

    captured = capsys.readouterr() # Don't repeat: buffer is cleared here
    info = captured.out
    err  = captured.err

    assert info == '[INFO] Hello\n'
    assert err  == '[ERROR] Oops..\n'