> If you mock everything, you are not really "testing" anything but your internal logic. That's the purpose of unit tests. They do not exclude the need to perf

> If you mock everything, you are not really "testing" anything but your internal logic. That's the purpose of unit tests. They do not exclude the need to perform other kinds of test. Integration tests, contract tests, stress tests - all those will focus on different facets of a system. > Most unit tests are written to ease the development. After finishing the development, they are safe to delete. This is especially bad advice, unless no one will never touch that codebase ever again. I saw old unit tests highlight bugs that would have been introduced by new code many times over the years. > TDD and exhaustive unit testing make the maintenance process harder because you don't know if a test is useful or not. Then, as a developer, remove unit tests that became useless. Code coverage is a measurement. If you turn it into a goal, it will become useless. If you have "useless" unit tests, it tells me that some unit tests were written as padding to move code coverage up.