unit testing - Python Caplog not capturing custom logger but capturing default logger

Question

I have a custom logger, logging to stdout set at level DEBUG

class MyLogger(Logger):
    def __init__(self, name):
        super().__init__(name)
        stdout = StreamHandler(sys.stdout)
        stdout.setLevel(10)
        self.addHandler(stdout)

class Foo:
    def __init__(self):
        self.log = MyLogger(__name__)

The logger works with the below example:

f = Foo()
f.log.debug("Test logger")

This prints Test logger to stdout

I am trying to do some unittesting and using caplog to assert that certain logs occur. Like below:

def test_fetch(caplog):
    f = Foo()

    with caplog.at_level(logging.DEBUG):
        f.log.debug("Test logger again")
    assert "Test logger again" in caplog.text

This test fails since caplog is empty at the assert statement (or anywhere else). The same test with the standard logger however, passes:

def test_fetch(caplog):
    # f = Foo()
    with caplog.at_level(logging.DEBUG):
        logging.getLogger(__name__).debug("Test logger again")
    assert "Test logger again" in caplog.text

Why is this happening?

question from:https://stackoverflow.com/questions/65951036/python-caplog-not-capturing-custom-logger-but-capturing-default-logger

Answer 1

Waitting for answers