That's actually a tough question and officiel doc mostly stick to "here's how to setup things until we have a more dedicated package"

I am writing a course to go more deeply in this area, I've opened the waitlist: https://course.nextjspatterns.com/testing-qa-react-server-components-a-next-js-pattern

you'll want to avoid "testing the framework"

so you're not testing Drizzle but more if your actions correctly make use of Drizzle

RSCs/Server Actions are deeply integrated with data so it's hard to unit test them

you would have to play around with dependency injections to replace drizzle with a mock you can observe

other ideas are setting end-to-end testing of your Next app

basically Next turns Server Actions into POST endpoint

so you could either run Next so you can test this POST endpoint via synthetic user interaction

or test the server action directly by calling it in Jest

sorry I've opened more questions than I answered hope it helps ':)

Thanks, just joined the waiting list 🙂

Yeah I think I understand what you mean by 'dont test the framework'. In java is quite easy to setup a in-memory docker database instance and just start from there. Or even mock the DAOs like you mentioned. Maybe my app is not well structured. If I had another layer on top of Drizzle (like DAO/or Service). Maybe it would be easy to inject a mock instead. But somethings when I test stuff with mocks, feels like I'm not really testing stuff, lol it might just be me though.

But again, I have no idea on how to actually set this up so for now I might stick to an end-to-end approach.
Any recommendations?

You could do some integration testing like having an actual drizzle db (don't know if it's realistic with this service?) + Jest to run the test by calling the server action as a function

it might be slow but it will be real

sometimes db have good mocks too like Mongo has an in-memory equivalent that is good and fast for testing

but it depends

I prefer integration/e2e too there, and keep unit for more algorithmic logic like if your action happens to have a zillion conditions it might be worth mocking the db and focusing on testing the function

Thank you Eric ❤️ Do you mind if I leave this thread unanswered to see if we can get other people to collaborate and give us their opinion?

no problem of course!

@Eric Burel looks like we got some news here:
https://nextjs.org/docs/app/building-your-application/testing

Didnt read it yet =] But wanted to share with you regardless

yes thanks! I've seen this page I think, it's good but talks a lot about setup

recently I had the chance to study end-to-end testing and the research paper around that,

they sometimes have mitigated return on investment because of their fragility

I think a big part of the content I'll create will be focused on that

but yeah otherwise that's a great starting point for a good setup, the rest often comes naturally trying and learning and testing different libs