Pytest: Mocking slow external API call - manually replace function

We can create a function (we call it mocked_remote_compute) that we’ll use to replace the remote API call. However, ee don’t need to re-implement the whole complex algorithm of computing the square of numbers provided by the remote service. It is enough that we hard-code the responses we should get from the API for the values we are going to use in the tests.

Then we can manuall monkey-patch the method in the externalapi library.

import mymath

def mocked_remote_compute(x):
    print(f"mocked received {x}")
    if x == 3:
        return 9
    if x == 4:
        return 16
    raise Exception (f"The value {x} isn't supported by the mock")

mymath.externalapi.remote_compute = mocked_remote_compute

def test_compute():
    assert mymath.compute(3, 4) == 5

#def test_other():
#    res = mymath.compute(2, 7)
#    assert res == 7.28010988928

time pytest test_mymath.py