Do you need to do unit and integration testing if you already do functional testing? [closed]

Answer 1

It depends on whether your functional tests are automated or done manually. If it's the latter, then any kind of automated test suite is useful since the cost of running those unit / integration tests is far lower than running manual functional tests. You can show real ROI there. I would recommend starting with writing some integration tests and if time / budget allows in the future, take a look at unit testing then.