Comment by BeetleB

> unit vs integration tests is not an either/or. you need both, and in appropriate coverage amounts.

Agreed. But I also agree with the commenter that for documentation purposes, integration tests are an order of magnitude more useful.

> a common way to think about this is called the "test pyramid" - unit tests at the base, supporting integration tests that are farther up the pyramid.

I used to be a believer in that pyramid, but my experience has shown me it depends on the project. Wherever it's feasible (i.e. doesn't involve long test times), I've found integration tests to be far more useful than unit tests. I've had experiences where I'd do a project and have really high unit test coverage, only to unveil fairly trivial bugs. The reverse hasn't happened - if I start a project with solid integration tests, I almost never encounter trivial bugs.

Generally, I now write integration tests and mock away time consuming/resource heavy parts (e.g. network calls, DB calls, etc). Better for documentation. Better for testing.