Unit tests are great if you need to drill down and verify a very specific piece of logic. Integration tests on the other hand are very useful if you need to tes

Unit tests are great if you need to drill down and verify a very specific piece of logic. Integration tests on the other hand are very useful if you need to test the overall system, especially if testing smaller parts is not possible or does not make sense. For instance, in my company we have developed an internal tool that allows external translators to directly translate resource strings in our database and VCS. Parts of this system are in unit tests (like the parts recognizing what the language of a file is), but the interop with the VCS is not something that makes sense to isolate. Therefore the only tests for that parts are through the integration tests.