Mutational tests
When you have a very simple application it’s not so important to test every edge case but in a project, in the very complex domain, the priority of it will increase. The more high-quality the tests, the more high-quality the code. Mutational tests will help you with making sure you did not miss some a variant of the flow in your code.
How it works Mutational testing is a test which runs other test several times but with a bit changed production code in every iteration.