Consider a module that allows to register event handlers and fires them at some condition: # mymodule/myfile.py _event_handlers = [] def register_event_handler(handler): _event_handlers.append(handler) def fire_event_handlers(): for handler in _event_handlers: handler() I now want to test that the registration of an event handler works: # tests/test_mymodule.py from mymodule.myfile import register_event_handler, fire_event_handlers def test_event_handler(): def example_handler(): pass register_event_handler(example_handler) fire_event_handlers() # assert example_handler was called How do I test if my function example_handler is called? There are some similar test cases that use unittest.mock (e.g. How to assert that nested function called pytest), but as I do not want to mock any existing function of the module, I do not see how to use it here. Continue reading...
