When should you delete [unit tests](/pages/Unit%20test.txt)?

> More tests are better, but if two tests are redundant with respect to each other, should you keep them both around? That depends on two criteria.
>
> - The first criterion for your tests is confidence. Never delete a test if it reduces your confidence in the behavior of the system.
> - The second criterion is communication. If you have two tests that exercise the same path through the code, but they speak to different scenarios for a reader, leave them alone.
>
> That said, if you have two tests that are redundant with respect to confidence and communication, delete the least useful of the two.
>
> --Chapter 32, [Test-driven development: by example](/pages/Test-driven%20development%20-%20By%20example.txt)