"3. Non intrusive arbitrary function and class mocking: No need to use virtual function interfaces, mock classes, and dependency injection, which couple your li

"3. Non intrusive arbitrary function and class mocking: No need to use virtual function interfaces, mock classes, and dependency injection, which couple your library design with the way the mocking framework works. unittest uses monkey-patching through elfspy so mocking is as transparent as possible." I think such an approach is short-sighted. It means that unit tests only end up testing your code from a functional point of view. By using dependency injection/mocking, unit tests also become a way of validating that the API of your code is pleasant to work with. If your code can be tested through mocks, it means you've written something that can be reused, embedded and extended. See also: https://en.wikipedia.org/wiki/SOLID https://en.wikipedia.org/wiki/SOLID