Recently I've been finding myself writing an increasing amount of integration tests over unit tests. They are typically more difficult to write, though I enjoy the safety net of knowing I'm not breaking user-facing features. I haven't been a fan of most of the existing frameworks with nested callbacks, or huge function chains with inline assertions. As people become more familiar with standardized async functions, I feel that they + mocha can be used as a test library which is very easy to reason about.