pytest-automock

Automock fixtures for pytest.

automock

Autogenerated method mocks for objects. Supports both sync/async methods.

Lets say you have some module mymod.py:

import time

class T:

    def do_job(self, x, y):
        s = x + y
        time.sleep(s)
        return s

And you want to create mocks for your tests, but you are too lazy to write them... conftest.py:

import pytest
import mymod

@pytest.fixture(autouse=True)
def _mocks(automock):
    with automock((mymod, "T")):
        yield

test_t.py:

import mymod

def test_job():
    t = mymod.T()
    assert t.do_job(1, 2) == 3
    assert t.do_job(2, 3) == 5

If you run pytest on this setup, then you will see fail:

$ pytest -x
...
E           RuntimeError: Mock is locked, but '__init__' wanted

automock can work in two modes: locked and unlocked. Locked mode is default, real methods calls of mocked objects are not allowed in this mode. So, above error says that we can't call __init__ of our T. In locked mode there are no mock-files updates also.

To allow real calls and mocks generation automock provides extra cli argument to pytest call --automock-unlocked

$ pytest -x --automock-unlocked
...
test_t.py .
...
1 passed in 8.08s

After that you can see that tests/mocks/test_job/T file was created. This is mock for your test sequence. Now you can rerun tests and see what happens (you can omit --automock-unlocked key for ensurance, that real object will not be touched).

$ pytest -x
...
test_t.py .
1 passed in 0.06s

API

automocker(*pairs, storage="tests/mocks", unlocked=None)

• pairs: pair/tuple of object/module and attribute name (str)
• storage (str or Path): root path for storing mocks
• unlocked (bool): mode selector (if omited, selected by --automock-unlocked)

Pros

• Easy to use
• Speed up tests
• Mock any object
• Mock functions

Cons

• No support for dunder methods (can be partly solved)
• No support for sync/async generators/contexts
• No black and white lists of methods for mocking (can be solved)
• Races will break tests, since order counts

automock_unlocked

Fixture with default mode from cli parameter.