I m running into an issue where I m using `runBlockingTest`

Question

I m running into an issue where I m using `runBlockingTest` and `advanceUntilIdle` and I think it s fooling kotest into thinking the test has timed out

bbaldino · Answer

kotest complains about `Test did not complete within 600000ms` but I watch the test and know it didn t sit for a minute

bbaldino · Answer

I m using `runBlockingTest` within the top `context` block maybe that s wrong Trying to repro with a small example maybe I m doing something dumb

Shalom Halbert · Answer

Can you share a code sample

bbaldino · Answer

Yeah trying to get something together

bbaldino · Answer

Ok I think this shows what I m seeing

bbaldino · Answer

```class FooTest ShouldSpec context top runBlockingTest context middle context bottom launch delay Long MAX VALUE latch countDown advanceUntilIdle should something latch count shouldBe 0 ```

bbaldino · Answer

That will fail instantly complaining `Test did not complete within 600000ms`

bbaldino · Answer

I m guessing because the fake clock of `runBlockingTest` gets used at some point by kotest to check for timeout

Shalom Halbert · Answer

Is it possible that the amount of time is an issue If you make the `delay` 590000 doe the issue persist You could be impacted by the the `advanceUntilIdle`

Shalom Halbert · Answer

In which case you d need to increase the test s timeout period

bbaldino · Answer

Yeah that s what I m guessing it is

bbaldino · Answer

Hm even if I make the delay `30000` I see the same thing

bbaldino · Answer

Ah it s probably because the `withTimeout` is effectively done within `runBlockingTest` so `advanceUntilIdle` goes until that finishes as well

bbaldino · Answer

If I move `runBlockingTest` to within the bottom `context` it s fine

bbaldino · Answer

That won t work so well with my real test but at least that probably explains what s happening

sam · Answer

what does run blocking test do

bbaldino · Answer

Is part of kotlinx coroutines test

sam · Answer

is that what provides advance til idle

sam · Answer

so you can test delays

bbaldino · Answer

It s basically a helper for testing coroutine code more deterministically

bbaldino · Answer

Yeah

sam · Answer

interesting

bbaldino · Answer

I was thinking of working around this by rewriting the test to avoid the nesting and just doing isolated test cases

bbaldino · Answer

But where does the `withTimeout` get applied for a test case

sam · Answer

it gets added every time a test block starts

bbaldino · Answer

Whatever adds the `withTimeout` would have to be outside `runBlockingTest` I think

bbaldino · Answer

Where test block is defined as what A `should` in this case

sam · Answer

so withtimeout is added by the TestExecutor class in kotest before user code is invoked

sam · Answer

yep any kotest lambda block

sam · Answer

it will add a withTimeout at every level

bbaldino · Answer

Hm

bbaldino · Answer

It works with `runBlockingTest` wrapping a `should` block ok

sam · Answer

so you might have more success in this case by using a flat structure dropping the context

bbaldino · Answer

So maybe it s that it can t be outside a `context`

bbaldino · Answer

Yeah looks like it

sam · Answer

it might be that the withTimeout runs and then there s another withTimeout for the nested scope

bbaldino · Answer

Yeah some `withTimeout` must be run within the `runBlockingTest` so it becomes a child of that scope so then `advanceUntilIdle` advances until that finishes as well I think

sam · Answer

yep because you re putting the test coroutine context outside of context so that s why