Thanks!

I've been looking at the documentation, and I still do not like it (the documentation). It is not wrote to learn it with ease.

For example, it talks about things like Motivation (no relevant to learn it), or what's included. It also talks about caching, which is not a good topic for the non-initiated. But what makes me think that in some cases is better to avoid it is that it is an extra overhead in the bundle (as they say: additional 9 + 2kb.

I do not had read it very deeply yet (it is the kind of documentation that you have to read several times), and I still do not know how it updates the state. I hope it saves things like isLoading in the state, so multiple components can act according to it.

About the competitive disadvantage, I do not agree. Write three more lines is not so costly. And, if they are good, they will find ways to refactor them together. That is the TDD way :-)

Anyway, all the tests that I have done, are still necessary. You need to check that it loads correctly the data from the endpoint, and shows it correctly, and it synchronizes correctly (at least how it reports it for the user). Nothing about it is implemented by RTK Query, and the rest are implementation details. The tests of RTK Query are not about my program business rules, only about if they call correctly to fetch, which is irrelevant to my business rules. So, nothing changes.