TestLifecycleOwner hangs inside of runTest [259344129]

Fixed

Bug

Status Update

No update yet.

Description

ji...@gmail.com

created issue #1

Nov 16, 2022 07:11PM

Component used: TestLifecycleOwner

Version used: 2.5.1

Devices/Android versions reproduced on: N/A

When used inside of runTest,

@OptIn(ExperimentalCoroutinesApi::class, ExperimentalStdlibApi::class)
class TestLifecycleOwnerTest {
  @Test
  fun testLifecycleOwnerStuff() = runTest(dispatchTimeoutMs = 5000) {
    Dispatchers.setMain(coroutineContext[CoroutineDispatcher]!!)
    val lifecycleOwner = TestLifecycleOwner()

    lifecycleOwner.currentState = Lifecycle.State.RESUMED
    Dispatchers.resetMain()
  }
}

...will hang and never return (not even after dispatchTimeoutMs expires)

Comments

sa...@google.com <sa...@google.com> #2Nov 16, 2022 09:28PM

Hi, are you able to step through and see which line it is hanging on? Also, what are you specifically trying to test here?

ji...@gmail.com <ji...@gmail.com> #3Nov 16, 2022 10:11PM

Hi, are you able to step through and see which line it is hanging on?

It hangs on the following line:

lifecycleOwner.currentState = Lifecycle.State.RESUMED

Specifically, it hangs when currentState's setter calls runBlocking. runBlocking is not safe to call from a coroutine.

Also, what are you specifically trying to test here?

Sorry, my naming wasn't clear. This might make it more clear:

@OptIn(ExperimentalCoroutinesApi::class, ExperimentalStdlibApi::class)
class TestLifecycleOwnerTest {
  @Test
  fun canAssignToCurrentStateInRunTest() = runTest(dispatchTimeoutMs = 5000) {
    Dispatchers.setMain(coroutineContext[CoroutineDispatcher]!!)
    val lifecycleOwner = TestLifecycleOwner()

    lifecycleOwner.currentState = Lifecycle.State.RESUMED
    Dispatchers.resetMain()
  }
}

Assigning to currenState is basic functionality for using TestLifecycleOwner.

Our current workaround is to use UnconfinedTestDispatcher. UnconfinedTestDispatcher forces behaviors on us that StandardTestDispatcher does not, though, so this is not great.

il...@google.com <il...@google.com> May 10, 2023 11:13PM

Assigned to sa...@google.com.

sa...@google.com <sa...@google.com> Aug 7, 2023 01:03PM

Accepted by sa...@google.com.

ap...@google.com <ap...@google.com> #4Aug 25, 2023 04:53PM

Marked as fixed.

Project: platform/frameworks/support
Branch: androidx-main

commit 7c76b7013a0229dd0f75cedd910a5005d53e52f3
Author: Sanura Njaka <sanura@google.com>
Date: Mon Aug 07 10:43:36 2023

Add new API to fix TestLifecycleOwner hanging inside of runTest

The use of runBlocking in TestLifecycleOwner causes
tests to hang when the api is used from the context of
another coroutine (such as runTest). To fix this, we
have added a suspending function to allow using
TestLifecycleOwner from within a coroutine.

RelNote: "`TestLifecycleOwner` now includes the suspending
function `setCurrentState()` to give users the option of using `TestLifecycleOwner` from within a coroutine."
Test: testSetCurrentStateInRunTest
Fixes: 259344129

Change-Id: I329de3d76bcd7fa5e04077916ff551f9f2f3f864

M lifecycle/lifecycle-runtime-testing/api/current.txt
M lifecycle/lifecycle-runtime-testing/api/restricted_current.txt
M lifecycle/lifecycle-runtime-testing/build.gradle
M lifecycle/lifecycle-runtime-testing/src/androidTest/java/androidx/lifecycle/testing/TestLifecycleOwnerAndroidTest.kt
M lifecycle/lifecycle-runtime-testing/src/main/java/androidx/lifecycle/testing/TestLifecycleOwner.kt

https://android-review.googlesource.com/2695369

il...@google.com <il...@google.com> #5Aug 29, 2023 04:03PM

We've added a suspend fun setCurrentState(Lifecycle.State) method on TestLifecycleOwner that keeps the requirement of dispatching all events on the coroutineDispatcher you've passed on TestLifecycleOwner's constructor while not blocking the current thread. This will be available in Lifecycle 2.7.0-alpha02.

The follow up bug, b/297880630 tracks adding a Lint warning for the current non-suspending version to point developers to use the new API if they are within a suspending context.

pr...@google.com <pr...@google.com> #6Sep 6, 2023 07:56PM

The following release(s) address this bug.It is possible this bug has only been partially addressed:

androidx.lifecycle:lifecycle-runtime-testing:2.7.0-alpha02