OFC Spring does lots of things (too many things), but that varies project to project based on what series of Spring-related libraries are being used.
More likely I'll see non Spring-core annotations like @RestController + @RequestMapping-attributes and have to figure a standard way to mock up some of what Spring does just to assert the outputs. Perhaps there will be a series of full functional tests which requires a setup/teardown. Maybe the project just ignores endpoint tests and focus on the less Spring annotated business logic claiming "it's simple enough".
Spring has resulted in slow, complex, and incomplete (coverage) testing almost anywhere it's used because it's literally hiding functionality behind a runtime composition that you can't access casually by calling a routine.
It's problematic because it's complex and the versions
Other classes/components should in the general case be written as POJOs. The dependent components can be mocked/injected simply by using the constructor.
I would confidently say, this philosophy is dead wrong. Integration test are useful, but you still want the unit tests to ensure that the code paths and side effects are maintained. With runtime composition, this is much harder. Java sacrificed what we do know for a grand experiment of doing as much as possible in pre-processing, breaking (sacrificing) the known concept of code reliability in the hopes that someone else would figure out a way to handle the testing implications down the line. Java Testing went from a gold standard to an afterthought with annotations. This is how important getting additional composition turned out to be, but at what cost?
> spring has really great test suits for these use cases.
@SpringBootTest requires booting up Spring just to add in the runtime composition. It's both unnecessarily time consuming and problematic to have to predict composition rather than observing it directly. Now you have to memorize what Spring might do, given annotations that can be anywhere AND the code you are trying to test. Nightmare stuff.
