Mocking a function in a process started with multiprocessing.Process

[Norman Robins]

Is it possible to mock out a function in a process started with
multiprocessing.Process? AI tells me it is, but I have not gotten it to
work.

The use case is that I have a server I want to write tests for. I want the
tests to start up the server, but I need to mock out the JWT based auth
functions in the server.

If it is possible, perhaps I am doing something wrong.

The function I want to mock out is in foo.bar.baz.validate_jwt`.

The server imports it as from .baz import validate_jwt. I have tried to
mock it many ways, here is the latest attempt:

@pytest.fixture(scope="module")
def mock_get_public_key():
return PUBLIC_KEY

@patch('foo.bar.baz.validate_jwt')
def test_fn(mock_validate_jwt, mock_get_public_key):

I also tried `@patch('foo.bar.main.validate_jwt')`

But no matter what I tried the real functions get called.

Here is an example:

In directory foo/bar file baz.py

def get_public_key(token: str) -> str:
print("in get_public_key)

def validate_jwt(token: str) -> dict
public_key = get_public_key(token)
print("in validate_jwt)

In directory foo/bar file main.py:

from .baz import validate_jwt

def server(token):
valid = validate_jwt(token)

In my test code, which is in test/test_main.py (test and foo are at the
same level)

@pytest.fixture(scope="module")def mock_get_public_key():
    return PUBLIC_KEY
def run_server(port):
    from foo.bar.main import start
    start(is_prod=False, port=port)
@pytest.fixture(scope="module")def mock_validate_jwt(token):
    return {"user": "test_user"}
@pytest.fixture(scope="module")def start_server():
    port = 8002
    server_process = multiprocessing.Process(target=run_server, args=(port,))
    server_process.start()

    max_retries = 10
    for i in range(max_retries):
        try:
            response =
requests.get(f"http://127.0.0.1:{port}/echo?message=test")
            if response.status_code == 200:
                break
        except requests.ConnectionError:
            time.sleep(1)
    else:
        pytest.fail("Server did not start in time")
@pytest.mark.usefixtures("start_server")@patch('dispatcher.main.validate_jwt')def
test_function(mock_validate_jwt, mock_get_public_key):
    ,
    .
    .





When test_function runs the real validate_jwt runs, not my mock.