PyTest: compare numbers relatively

def get_number():
    return 23

def test_get_number():
    assert get_number() < 0

$ pytest -q test_number_less_than.py

Output:

F                                                                        [100%]
=================================== FAILURES ===================================
_______________________________ test_get_number ________________________________

    def test_get_number():
>       assert get_number() < 0
E       assert 23 < 0
E        +  where 23 = get_number()

test_number_less_than.py:5: AssertionError
=========================== short test summary info ============================
FAILED test_number_less_than.py::test_get_number - assert 23 < 0
1 failed in 0.09s