Has anyone had issues with `assertFailsWith` When using it i

Question

Has anyone had issues with `assertFailsWith` When using it in a multiplatform project I can consistently reproduce an issue on the JS platform everything is fine on JVM When I use `assertFailsWith SomeException class ` everything works as expected the exception is thrown the test pass When I use `assertFailsWith lt SomeException gt ` variant the test fails as if no exception was thrown by the block Only a couple of my tests work properly no matter the form used but all the others fail consistently with the 2nd form and succeed with the 1st form and I have no idea how this is possible both are inline functions calling the same 3rd function I really don t get it

Joffrey · Answer

Looks like it creates a CoroutinesInternalError somehow because I can see this in the standard output before the test fails ```oroutinesInternalError message q7r8iu$ 0 Fatal exception in coroutines machinery for CancellableContinuation DispatchedContinuation WindowDispatcher 1 object Object CancelledContinuation JobCancellationException Parent job is Cancelling job=TimeoutCoroutine timeMillis=1000 Cancelled 2 3 Please read KDoc to handleFatalException method and report this incident to maintainers cause us9j0c$ 0 ClassCastException message 8yp7un$ 0 Illegal cast cause th0jdv$ 0 null name ClassCastException name CoroutinesInternalError ```

Joffrey · Answer

On nodeJS the output is easier to read ```CoroutinesInternalError Fatal exception in coroutines machinery for CancellableContinuation DispatchedContinuation NodeDispatcher 1 object Object CancelledContinuation JobCancellationException Parent job is Cancelling job=TimeoutCoroutine timeMillis=1000 Cancelled 2 3 Please read KDoc to handleFatalException method and report this incident to maintainers at CancellableContinuationImpl DispatchedTask handleFatalException mseuzz$ Users jbion projects krossbow build js packages imported kotlinx coroutines core 1 3 3 kotlinx coroutines core js 32457 16 at CancellableContinuationImpl DispatchedTask run Users jbion projects krossbow build js packages imported kotlinx coroutines core 1 3 3 kotlinx coroutines core js 32450 10 at SetTimeoutBasedDispatcher$ScheduledMessageQueue MessageQueue process Users jbion projects krossbow build js packages imported kotlinx coroutines core 1 3 3 kotlinx coroutines core js 35741 15 at Users jbion projects krossbow build js packages imported kotlinx coroutines core 1 3 3 kotlinx coroutines core js 35557 30 at processTicksAndRejections internal process task queues js 75 11 message q7r8iu$ 0 Fatal exception in coroutines machinery for CancellableContinuation DispatchedContinuation NodeDispatcher 1 object Object CancelledContinuation JobCancellationException Parent job is Cancelling job=TimeoutCoroutine timeMillis=1000 Cancelled 2 3 Please read KDoc to handleFatalException method and report this incident to maintainers cause us9j0c$ 0 ClassCastException Illegal cast at throwCCE 0 Users jbion projects krossbow build js packages imported kotlin 1 3 70 kotlin exceptionUtils kt 15 11 at NodeDispatcher CoroutineDispatcher releaseInterceptedContinuation k98bjh$ Users jbion projects krossbow build js packages imported kotlinx coroutines core 1 3 3 kotlinx coroutines core js 1896 84 at Coroutine$StompSessionReceiptTests$send autoReceipt failsOnWebSocketError$lambda CoroutineImpl releaseIntercepted 0 Users jbion projects krossbow build js packages imported kotlin 1 3 70 kotlin coroutines CoroutineImpl kt 75 48 at Coroutine$sendAndWaitForReceipt 0 CoroutineImpl resumeWith tl1gpc$ Users jbion projects krossbow build js packages imported kotlin 1 3 70 kotlin coroutines CoroutineImpl kt 56 17 at ScopeCoroutine afterResume s8jyv4$ Users jbion projects krossbow build js packages imported kotlinx coroutines core 1 3 3 kotlinx coroutines core js 33020 14 at ScopeCoroutine AbstractCoroutine resumeWith tl1gpc$ Users jbion projects krossbow build js packages imported kotlinx coroutines core 1 3 3 kotlinx coroutines core js 412 8 at Coroutine$sendText 61zpoe$ CoroutineImpl resumeWith tl1gpc$ Users jbion projects krossbow build js packages imported kotlin 1 3 70 coroutines Continuation kt 53 5 at CancellableContinuationImpl DispatchedTask run Users jbion projects krossbow build js packages imported kotlinx coroutines core 1 3 3 kotlinx coroutines core js 32427 22 at SetTimeoutBasedDispatcher$ScheduledMessageQueue MessageQueue process Users jbion projects krossbow build js packages imported kotlinx coroutines core 1 3 3 kotlinx coroutines core js 35741 15 at Users jbion projects krossbow build js packages imported kotlinx coroutines core 1 3 3 kotlinx coroutines core js 35557 30 at processTicksAndRejections internal process task queues js 75 11 message 8yp7un$ 0 Illegal cast cause th0jdv$ 0 null name ClassCastException name CoroutinesInternalError ```