Bug: NullPointerException while mocking NavController on instrumentation tests

[juawcevada-circle]

Expected Behavior

I should be able to mock NavController on a Espresso test.

Current Behavior

Im having this crash when I'm mocking NavController on a Espresso test:
java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Object androidx.collection.SparseArrayCompat.get(int)' on a null object reference at androidx.navigation.NavGraph.findNode(NavGraph.java:171) at androidx.navigation.NavGraph.findNode(NavGraph.java:166) at androidx.navigation.ui.NavigationUI.findStartDestination(NavigationUI.java:570) at androidx.navigation.ui.AppBarConfiguration$Builder.<init>(AppBarConfiguration.java:124) at androidx.navigation.ui.ToolbarKt.setupWithNavController$default(Toolbar.kt:82)

Steps to Reproduce

Have a fragment with this the toolbar set up with NavControler:
val navController = findNavController() toolbar.setupWithNavController(navController)

Mock the Nav controller on the Espresso test:
private val navController :NavController = mockk(relaxed = true)

This should work with mockito, I didn't test it but google has a sample with it on their documentation:
https://developer.android.com/guide/navigation/navigation-testing

Context

• MockK version:1.9.3
• Kotlin version:1.3.31
• JDK version:1.8
• Type of test:instrumented test

Stack trace

java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Object androidx.collection.SparseArrayCompat.get(int)' on a null object reference
at androidx.navigation.NavGraph.findNode(NavGraph.java:171)
at androidx.navigation.NavGraph.findNode(NavGraph.java:166)
at androidx.navigation.ui.NavigationUI.findStartDestination(NavigationUI.java:570)
at androidx.navigation.ui.AppBarConfiguration$Builder.<init>(AppBarConfiguration.java:124)
at androidx.navigation.ui.ToolbarKt.setupWithNavController$default(Toolbar.kt:82)
at com.fundingcircle.investors.android.uk.features.sell.view.ConfirmSaleFragment.setUpToolbar(ConfirmSaleFragment.kt:60)
at com.fundingcircle.investors.android.uk.features.sell.view.ConfirmSaleFragment.onViewCreated(ConfirmSaleFragment.kt:40)
at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:892)
at androidx.fragment.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManagerImpl.java:1238)
at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:1303)
at androidx.fragment.app.BackStackRecord.executeOps(BackStackRecord.java:439)
at androidx.fragment.app.FragmentManagerImpl.executeOps(FragmentManagerImpl.java:2079)
at androidx.fragment.app.FragmentManagerImpl.executeOpsTogether(FragmentManagerImpl.java:1869)
at androidx.fragment.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManagerImpl.java:1824)
at androidx.fragment.app.FragmentManagerImpl.execSingleAction(FragmentManagerImpl.java:1696)
at androidx.fragment.app.BackStackRecord.commitNow(BackStackRecord.java:293)
at androidx.fragment.app.testing.FragmentScenario$1.perform(FragmentScenario.java:312)
at androidx.fragment.app.testing.FragmentScenario$1.perform(FragmentScenario.java:291)
at androidx.test.core.app.ActivityScenario.lambda$onActivity$1$ActivityScenario(ActivityScenario.java:535)
at androidx.test.core.app.ActivityScenario$$Lambda$0.run(Unknown Source:4)
at android.app.Instrumentation$SyncRunnable.run(Instrumentation.java:2124)
at android.os.Handler.handleCallback(Handler.java:789)
at android.os.Handler.dispatchMessage(Handler.java:98)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6938)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:327)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1374)

[oleksiyp]

Not sure about this one. Can you provide a sample project? Because it is pretty hard to deal with all this boilerplate project setup.

[smellouk]

Hi, I'm having the same issue with apollo client on instrumentation tests

@oleksiyp you can check with apollo client

@Test
  fun testSomething() {
    every {
      apolloClient.query(any<QueryClass>()) // <--- //java.lang.NullPointerException: Attempt to invoke virtual method //`ResponseFieldMapperFactory`
    } returns call
  }