Hey folks wave I m upgrading a project to ktor 1 5 3 and it

Question

Hey folks wave I m upgrading a project to ktor 1 5 3 and it breaks some tests when run on JVM iOS tests are fine In these tests a class is tested that provides a reactive interface to its underlying `HttpClient` instance by using Reaktive helpers to convert coroutines into `Observable` or other Reaktive types To do actual asserts Reaktive helpers like `TestObserver` are used ```fun `it does whatever a spider cat does` ktorMockServerManager is just a way to configure mock engine handlers ktorMockServerManager enqueueRequest sut doApiStuff test assertComplete ``` The tests are completely synchronous but as soon as I update ktor to 1 5 1 1 5 0 is fine though they start failing because by the time `assertComplete` is called the underlying coroutine hasn t yet finished so the tests fail If I add a `sleep` call like this ```fun `it does whatever a spider cat does` ktorMockServerManager enqueueRequest val observer = sut doApiStuff test sleep 1000 observer assertComplete ``` I wonder what change between 1 4 3 and 1 5 1 could lead to this and what s the way around it

Nikolay Kasyanov · Answer

looks like it this might be it the only real change to `MockEngine` since 1 4 3 added in 1 5 1 <https github com ktorio ktor commit a6d103f6c3f13c1a136a313112a47a6af7927137 diff 3d93b6d65cea408ebd78460acc5fea1e9fb27799795984595067d5e421f939d1>

Nikolay Kasyanov · Answer

I d appreciate any clues here cc < e5l> pray

Nikolay Kasyanov · Answer

This actually checks out on native `Dispatchers clientDispatcher` yields `Unconfined` dispatcher but on JVM it s `ClosableBlockingDispatcher`

Nikolay Kasyanov · Answer

thus tests don t on iOS but fail on JVM

e5l · Answer

I m not sure that I can guess what coroutine is stale It would be great to have more details Could you file an issue with coroutines dump and reproducer

Nikolay Kasyanov · Answer

I see I ll try get some more details thanks

Nikolay Kasyanov · Answer

Hey < e5l> I ll look into it but not sure about the timeline Here s what I can share now by the time previously Reaktive completable under test was already completed that s what I see in coroutine debugger The `ClosableBlockingDispatcher` was added to MockEngine in ktor 1 5 1 if I remember correctly Previously the same coroutine would have executed immediately on the `Unconfined` dispatcher

e5l · Answer

Yep that s expected The reason it was the same with Unconfined but we didn t await for running jobs

e5l · Answer

The main question is what job is running and how to stop it

Nikolay Kasyanov · Answer

if I expand `call context 2` here s what I see

Nikolay Kasyanov · Answer

``` call context 2 RUNNING on thread ktor client dispatcher worker 1 RUNNING findLoadedClass 1281 ClassLoader java lang loadClassOrNull 593 BuiltinClassLoader jdk internal loader loadClass 579 BuiltinClassLoader jdk internal loader loadClass 178 ClassLoaders$AppClassLoader jdk internal loader loadClass 522 ClassLoader java lang ByteReadChannel 45 ByteChannelCtorKt <http io ktor utils io|io ktor utils io> respond 75 MockUtilsKt io ktor client engine mock respond$default 73 MockUtilsKt io ktor client engine mock invokeSuspend 37 MockHttpClientFactory$get$1$2$1 com careem captain common networking mockserver execute 61 MockEngine io ktor client engine mock invokeSuspend 86 HttpClientEngine$executeWithinCallContext$2 io ktor client engine execute 61 MockEngine io ktor client engine mock invokeSuspend 86 HttpClientEngine$executeWithinCallContext$2 io ktor client engine resumeWith 33 BaseContinuationImpl kotlin coroutines jvm internal run 106 DispatchedTask kotlinx coroutines runSafely 571 CoroutineScheduler kotlinx coroutines scheduling executeTask 750 CoroutineScheduler$Worker kotlinx coroutines scheduling runWorker 678 CoroutineScheduler$Worker kotlinx coroutines scheduling run 665 CoroutineScheduler$Worker kotlinx coroutines scheduling ```

e5l · Answer

could you share the code of test as well

Nikolay Kasyanov · Answer

let me try

e5l · Answer

It looks like some coroutine from the test scope is not finished

e5l · Answer

You actually can setup `CoroutineTimeout` for test to get test timeout for all hanging coroutines

e5l · Answer

It will also print you all coroutines stack traces

Nikolay Kasyanov · Answer

good to know thanks I ll try to create a reproducer should be easier than I initially assumed

Nikolay Kasyanov · Answer

sending the reproducer to you as a direct message

e5l · Answer

You also can file a private issue in YT and share it only with Ktor team

louiscad · Answer

Or make the issue public but attach the reproducer privately slightly smiling face

Nikolay Kasyanov · Answer

sounds good

Nikolay Kasyanov · Answer