How can you override a function with a lambda using python mock?

Question

I have some code that uses Greenlet.spawn to call some code a little later. I just found out there was an exception that is getting raised in that code. It would have been caught by our tests but the spawn makes it run after the tests succeed.

I'm looking for a way to patch Greenlet.spawn so it immediately calls the passed in function.

I want to patch the test class and not have to add arguments to the tests. I've used patch for a lot of other stuff and I feel like it's gotta be able to do this but none of my googling has been fruitful.

Any ideas?

Answer 1

Figured it out:

@patch('skynet.middleware.Greenlet.spawn', classmethod(lambda cls,f: f()))

Seems obvious in retrospect, guess I just kept not getting it quite right.