There’s a world of difference between writing tests for a rest api endpoint vs other types of pesky code. Too big a difference really. Writing a bunch of tests

There’s a world of difference between writing tests for a rest api endpoint vs other types of pesky code. Too big a difference really. Writing a bunch of tests for your utility methods like a DateFormatter is obvious, but if you shackle up other abstract implementations with tests and strict type checking, you can easily make a piece of unalterable code (maybe that’s the point). The question is, what is the value in doing that? Why shackle up all parts of your codebase when only a few parts are critical? I’ll admit that I also lack (and have lacked) guidance on testing.