let’s say there is a Shape interface.
interface IShape { double Area(); }
A Rectangle class and a Triangle class implement it. Now should i write tests for:
- IShape interface and test both implementations in a single test file?
- Write tests for Rectangle and Triangle class separately, testing their implementation of Area() ?
- Do something else?
From what I see I am testing implementations either ways. How do you even test an interface without testing the implementation? Can someone please help clarify my doubts? Thanks!
Testing interface is not about exactly interface as language’s feature. It’s about testing outer public interface (public API) of you things, looking at it as a black-box and doesn’t matter what happens inside. That’s all it means.