Controversial suggestion (but its 6.0 we can make ...

# kotest-contributors

[sam]

Controversial suggestion (but its 6.0 we can make breaking changes) - should we replace instance per test/leaf with a new instance per root? 🧵

[sam]

The hoops we have to jump through to detect that a nested test is a "leaf" and then execute it in a new spec and repeating all the parent tests seems like something we should avoid to me.

[sam]

an instance per root makes much more sense, as those are known in advance and we don't need to do any runtime trickery

[sam]

That's probably a bit closer to what junit does too

[sam]

Benefits:
• could remove TestType completely (dynamic is already gone)
• Would be a step closer to aligning jvm and non-jvm
• would massively simplify the spec execution code
• would remove all the weird edge cases about when callbacks are invoked in extensions etc
• would allow better/simpler concurrency options

[LeoColman]

Personally, I don't use InstancePerLeaf that much, so it wouldn't impact me a lot.

That's probably a bit closer to what junit does too

This is I think a great point to raise. I think we should get closer to JUnit without sacrificing the Kotlin

Removing weird corner cases is also great for maintenability and stability of the code base.

I don't have anything against it, but my opinion might not be the best for this situation

[sam]

Still a decent amount to do, but this is what I have so far: https://github.com/kotest/kotest/pull/4626

[Alex Kuznetsov]

I see a lot of uses of InstancePerTest instead of clearing mocks. Is it going to be removed for good? If yes, migration to 6.0 might take quite a lot of time, unless we have an easy way to replace InstancePerTest

[sam]

The tests are almost done

[Shervin]

question:
I use instance per leaf, what are the downsides of the new changes for me?