Jest provides special matchers for mock functions:
- expect(mockFunc).toBeCalled(): This asserts that the mock function was called at least once
- expect(mockFunc).toBeCalledWith(arg1, arg2): This asserts that the mock function was called at least once with the specified arguments
- expect(mockFunc).lastCalledWith(arg1, arg2): This asserts that the last call to the mock function was passed the specified arguments
- expect(mockFunc).toHaveBeenCalledTimes(number): This asserts that the mock function has been called exactly number times