> You mock the external service to unit test the internal logic You only need the output produced by that external service or the the input expected by that se

> You mock the external service to unit test the internal logic You only need the output produced by that external service or the the input expected by that service. For example, I can pass in a data structure or object representing the HTTP request to the method that I'm unit testing, but I don't need to mock a client to generate those requests to test that logic.