Edit Solved by disabling parallel run on tests in AS Hey all

Question

Edit Solved by disabling parallel run on tests in AS Hey all another Instrumented Testing crash I could use some help with It seems that I get this crash depending on the order that my tests are executed Stacktrace ```java lang NullPointerException at androidx compose ui layout SubcomposeLayoutState disposeCurrentNodes$ui release SubcomposeLayout kt 386 ```

Tim Malseed · Answer

Composable code ``` Composable fun HomeScreen viewModel HomeViewModel = hiltViewModel onNavigate destination NavigationDestination gt Unit = val authenticationState by viewModel authenticationState collectAsState when authenticationState is UserAuthenticationState Undetermined gt LoadingScreen is UserAuthenticationState Unauthenticated gt LaunchedEffect authenticationState onNavigate NavigationDestination Root Onboarding is UserAuthenticationState Authenticated gt HomeScreen Composable fun HomeScreen val navController = rememberNavController val navBackStackEntry by navController currentBackStackEntryAsState val currentDestination = navBackStackEntry destination Scaffold bottomBar = BottomAppBar modifier = Modifier backgroundColor = MaterialColors background BottomNav currentDestination screen gt navController navigate screen route modifier = Modifier semantics testDescription = Home Screen padding gt HomeNavHost navController = navController modifier = Modifier padding padding ``` HomeNavHost ``` Composable fun HomeNavHost navController NavHostController modifier Modifier = Modifier NavHost navController = navController startDestination = NavigationDestination Home Coach route modifier = modifier composable NavigationDestination Home Coach route CoachScreen composable NavigationDestination Home Discover route DiscoverScreen composable NavigationDestination Home Library route LibraryScreen composable NavigationDestination Home You route YouScreen composable NavigationDestination Home Search route SearchScreen ```

Tim Malseed · Answer

I have two tests one for the NavHost and one for the Compose UI

Tim Malseed · Answer

NavHost tests ``` HiltAndroidTest class HomeNavHostTest get Rule order = 0 var hiltRule = HiltAndroidRule this get Rule order = 1 val composeTestRule = createAndroidComposeRule lt MainActivity gt private lateinit var navController NavHostController Before fun setup hiltRule inject composeTestRule setContent navController = rememberNavController HomeNavHost navController = navController Test fun initialDestinationIsCoach assert navController currentDestination route == NavigationDestination Home Coach route Test fun navigateToCoachScreen runBlocking withContext Dispatchers Main navController navigate NavigationDestination Home Coach route assert navController currentDestination route == NavigationDestination Home Coach route ``` UI Tests ``` HiltAndroidTest class HomeScreenTest get Rule order = 0 var hiltRule = HiltAndroidRule this get Rule order = 1 val composeTestRule = createAndroidComposeRule lt MainActivity gt Before fun setup hiltRule inject composeTestRule setContent HomeScreen Test fun bottomTabsAreDisplayed composeTestRule onNodeWithTestDescription coach assertIsDisplayed composeTestRule onNodeWithTestDescription discover assertIsDisplayed composeTestRule onNodeWithTestDescription library assertIsDisplayed composeTestRule onNodeWithTestDescription you assertIsDisplayed composeTestRule onNodeWithTestDescription search assertIsDisplayed Test fun initialDestinationIsCoach composeTestRule onNodeWithTestDescription Coach Screen assertIsDisplayed ```

Tim Malseed · Answer

If I run the UI tests only they all run just fine

Tim Malseed · Answer

It seems the crash only happens when the UI tests are run after the NavHost tests

Tim Malseed · Answer

So maybe some state is lingering between tests

Tim Malseed · Answer

Full Stack Trace ```E AndroidJUnitRunner An unhandled exception was thrown by the app java lang NullPointerException at androidx compose ui layout SubcomposeLayoutState disposeCurrentNodes$ui release SubcomposeLayout kt 386 at androidx compose ui layout SubcomposeLayoutKt$SubcomposeLayout$3$invoke$$inlined$onDispose$1 dispose Effects kt 484 at androidx compose runtime DisposableEffectImpl onForgotten Effects kt 85 at androidx compose runtime CompositionImpl$RememberEventDispatcher dispatchRememberObservers Composition kt 793 at androidx compose runtime CompositionImpl dispose Composition kt 496 at androidx compose ui platform WrappedComposition dispose Wrapper android kt 171 at androidx compose ui platform WrappedComposition onStateChanged Wrapper android kt 179 at androidx lifecycle LifecycleRegistry$ObserverWithState dispatchEvent LifecycleRegistry java 354 at androidx lifecycle LifecycleRegistry backwardPass LifecycleRegistry java 284 at androidx lifecycle LifecycleRegistry sync LifecycleRegistry java 302 at androidx lifecycle LifecycleRegistry moveToState LifecycleRegistry java 148 at androidx lifecycle LifecycleRegistry handleLifecycleEvent LifecycleRegistry java 134 at androidx lifecycle ReportFragment dispatch ReportFragment java 68 at androidx lifecycle ReportFragment$LifecycleCallbacks onActivityPreDestroyed ReportFragment java 224 at android app Activity dispatchActivityPreDestroyed Activity java 1516 at android app Activity performDestroy Activity java 8312 at android app Instrumentation callActivityOnDestroy Instrumentation java 1364 at androidx test runner MonitoringInstrumentation callActivityOnDestroy MonitoringInstrumentation java 756 at android app ActivityThread performDestroyActivity ActivityThread java 5374 at android app ActivityThread handleDestroyActivity ActivityThread java 5420 at android app servertransaction DestroyActivityItem execute DestroyActivityItem java 47 at android app servertransaction ActivityTransactionItem execute ActivityTransactionItem java 45 at android app servertransaction TransactionExecutor executeLifecycleState TransactionExecutor java 176 at android app servertransaction TransactionExecutor execute TransactionExecutor java 97 at android app ActivityThread$H handleMessage ActivityThread java 2210 at android os Handler dispatchMessage Handler java 106 at android os Looper loopOnce Looper java 201 at android os Looper loop Looper java 288 at android app ActivityThread main ActivityThread java 7839 at java lang reflect Method invoke Native Method at com android internal os RuntimeInit$MethodAndArgsCaller run RuntimeInit java 548 at com android internal os ZygoteInit main ZygoteInit java 1003 ```

Tim Malseed · Answer

The left shows the tests passing independently The right shows the same test failing after the other tests run

Tim Malseed · Answer

Interestingly if I out comment the `setContent ` call in `MainActivity` the Activity being used by the `createAndroidComposeRule` due to the presence of Hilt the exception moves elsewhere

Tim Malseed · Answer

```java lang NullPointerException Attempt to invoke virtual method androidx compose ui graphics vector ImageVector com myapp android ui components common NavigationDestination$Home getImage on a null object reference at com myapp android ui components home HomeScreenKt$BottomNav$2$1$2 invoke HomeScreen kt 90 at com myapp android ui components home HomeScreenKt$BottomNav$2$1$2 invoke HomeScreen kt 88 at androidx compose runtime internal ComposableLambdaImpl invoke ComposableLambda jvm kt 107 at androidx compose runtime internal ComposableLambdaImpl invoke ComposableLambda jvm kt 34 ```

Tim Malseed · Answer

Which corresponds to this line `imageVector = screen image ` In BottomNav ``` Composable fun BottomNav currentDestination NavDestination onItemClick NavigationDestination gt Unit = BottomNavigation modifier = Modifier backgroundColor = MaterialColors surface NavigationDestination Home all forEach screen gt val selected = currentDestination hierarchy any it route == screen route == true BottomNavigationItem selected = selected alwaysShowLabel = selected icon = Icon imageVector = screen image contentDescription = stringResource id = screen titleResId Modifier semantics testDescription = screen route label = Text text = stringResource id = screen titleResId selectedContentColor = MaterialColors onBackground unselectedContentColor = MaterialColors onBackground copy alpha = ContentAlpha medium onClick = onItemClick screen ```

Tim Malseed · Answer

``` sealed class Home override val route String StringRes val titleResId Int val image ImageVector NavigationDestination route object Coach Home route = coach titleResId = R string home tab coach image = Icons Outlined EmojiPeople object Discover Home route = discover titleResId = R string home tab discover image = Icons Outlined Explore object Library Home route = library titleResId = R string home tab library image = Icons Outlined GridView object You Home route = you titleResId = R string home tab you image = Icons Outlined PersonOutline object Search Home route = search titleResId = R string home tab search image = Icons Outlined Search companion object val all List lt Home gt = listOf Coach Discover Library You Search ```

Tim Malseed · Answer

Edit This issue only occurs when running the tests inside of Android Studio

Tim Malseed · Answer

Oh and it s fixed by disabling parallel run

Tim Malseed · Answer

sob

Zach Klippenstein (he/him) [MOD] · Answer

Running parallel instrumentation tests seems risky in general since most of the testing infrastructure assumes only one app is active at a time I m surprised this would work even without compose

Tim Malseed · Answer

Yeah I wonder if maybe it shouldn t be the default in Android Studio

Tim Malseed · Answer

Obviously this is my own fault for not understanding the tools But do you think this could be an issue raised against AS

Zach Klippenstein (he/him) [MOD] · Answer

I didn t realize it was the default i didn t think i d ever seen it try to run parallel instrumentation tests

Tim Malseed · Answer

Yeah I didn t manually change that setting but who knows

Tim Malseed · Answer

Interestingly and frustratingly I m now getting this issue on the commandline via `connectedAndroidTest`

Tim Malseed · Answer

I m curious whether those are parallelized but can t seem to figure that out