📣 📣 📣 kotlinx.coroutines 1.6.0 is here! • Brand new

kotlinx-coroutines-test

module with reworked API and multiplatform support •

CoroutineDispatcher.limitedParallelism

and elastic

<http://Dispathers.IO|Dispathers.IO>

• Out-of-the-box support of new K/N memory model •

CopyableThreadContextElement

for mutable context elements • And a lot of improvements and bug fixes: https://github.com/Kotlin/kotlinx.coroutines/releases/tag/1.6.0 We also have a blogpost and video with additional details, examples and explanation

So this is using Kotlin 1.6? Didn't Kotlin 1.6 have a breaking bug? Why not Kotlin 1.6.10?

So is the expectation that by 1.7, most of the K/N community will have migrated to the new memory model? I'm a little surprised native-mt wouldn't be supported for one more release cycle in case people are slow to move over.

How do I test flows with that new runTest? Turbine always runs in a timeout:

@Test
  fun myTest() = runTest {
    flow {
      delay(10.milliseconds)
      emit(Unit)
    }.test {
      awaitItem() shouldBe Unit
    }
  }

See https://github.com/Kotlin/kotlinx.coroutines/blob/master/kotlinx-coroutines-test/README.md#virtual-time-support-with-other-dispatchers Turbine launches the

collect

of this flow in

Dispatchers.Unconfined

, which is not linked to `kotlinx-coroutines-test`: https://github.com/cashapp/turbine/blob/trunk/src/commonMain/kotlin/app/cash/turbine/FlowTurbine.kt#L86 So, the timeout runs with delay-skipping, whereas the flow body does not. I would suggest turning off the timeout, as our test framework will also fail if the system hangs.

@Test
    fun myTest() = runTest {
        flow {
            yield()
            delay(10.milliseconds)
            emit(Unit)
        }.test(0) {
            assertEquals(Unit, awaitItem())
        }
    }

Can you post your ideas here? https://github.com/cashapp/turbine/issues/71

Nah, it's the opposite, actually. They're running the timeout just fine (and if they implement the change, it's also going to be fine), it's the flow's body that should run on a different dispatcher.

It’s probably good if you communicate directly there as these two libraries closely belong together

I somehow missed the obvious solution that is not very verbose: https://github.com/cashapp/turbine/issues/42#issuecomment-868681072 So,

@Test
    fun myTest() = runTest {
        flow {
            delay(10.milliseconds)
            emit(Unit)
        }.flowOn(UnconfinedTestDispatcher(testScheduler))
        .test {
            assertEquals(Unit, awaitItem())
        }
    }

So should that be the default?