1) I haven't actually seen a tooling configuration that gives you the experience of having the concrete type in your code when you write code that uses an inter

1) I haven't actually seen a tooling configuration that gives you the experience of having the concrete type in your code when you write code that uses an interface (in e.g. golang or Java) for the sole purpose of swapping it out in a test. 2) Right. I agree. 3) It looks like your original post in this thread says "Do not make black box tests. Make white box tests"