def test_not_authenticated_if_password_doesnt_matches(
        authentication: Authentication) -> None:
    assert authentication.is_valid(username=EXISTING_USERNAME,
                                   password="******") is False
def test_authenticated_if_credentials_correct(
        authentication: Authentication) -> None:
    assert authentication.is_valid(username=EXISTING_USERNAME,
                                   password=CORRECT_PASSWORD) is True
def test_not_authenticated_if_username_doesnt_exists(
        authentication: Authentication) -> None:
    assert authentication.is_valid(username="******",
                                   password="******") is False