Hard to overstate the benefit of not having to rewrite your tests when you refactor. That's a concrete and difficult to ignore benefit of using higher level API

Hard to overstate the benefit of not having to rewrite your tests when you refactor. That's a concrete and difficult to ignore benefit of using higher level APIs. I find that the cost of writing a test is often not less than the cost of writing the code. If that is correct, it means that the system lifetime cost of authorship is much higher with unit tests. If all tests are unit tests the cost is almost 100% higher.