android - How to test androidx (proto) datastore, java.lang.ExceptionInInitializerError

Question

After working with datastore for some time and writing some business logic with it, I would like to test my classes / repository that use datastore. The problem I encounter is, how should I do this? I tried to create a context.createDatastore(...) with the test context, but I just got some errors. There are no official documentations about this or at least I couldn't find one.

Here is my current approach:

Interface

interface ShopFilterDataStoreRepository {
    val shopFilterProduct: Flow<ShopFilterProduct>
    val shopFilterList: Flow<ShopFilterList>

    suspend fun setValueProduct(newProduct: ShopFilterTempHolder)
    suspend fun setValueList(newList: ShopFilterTempHolder)
}

Implementation (Default Implementation used in production)

class ShopFilterDataStoreRepositoryImpl @Inject constructor(
    @ApplicationContext private val context: Context,
) : ShopFilterDataStoreRepository {

    private companion object {
        private const val SHOP_FILTER_PRODUCT_DATASTORE: String = "shop_filter_product_datastore"
        private const val SHOP_FILTER_LIST_DATASTORE: String = "shop_filter_list_datastore"
    }

    // this causes error because test context != applicationcontext
    private val nonVolatileProductDataStore = context.createDataStore(
        fileName = SHOP_FILTER_PRODUCT_DATASTORE,
        serializer = ShopFilterProductSerializer
    )

    // this causes error because test context != applicationcontext
    private val nonVolatileListDataStore = context.createDataStore(
        fileName = SHOP_FILTER_LIST_DATASTORE,
        serializer = ShopFilterListSerializer
    )

    override val shopFilterProduct: Flow<ShopFilterProduct>
        get() = nonVolatileProductDataStore.data

    override val shopFilterList: Flow<ShopFilterList>
        get() = nonVolatileListDataStore.data

    override suspend fun setValueProduct(newProduct: ShopFilterTempHolder) {
        if (newProduct.id == null || newProduct.mQuery == null) return
        nonVolatileProductDataStore.updateData { preferences ->
            preferences.toBuilder().apply {
                positionId = newProduct.id
                query = newProduct.mQuery
            }.build()
        }
    }

    override suspend fun setValueList(newList: ShopFilterTempHolder) {
        if (newList.id == null || newList.mQuery == null) return
        nonVolatileListDataStore.updateData { preferences ->
            preferences.toBuilder().apply {
                positionId = newList.id
                query = newList.mQuery
                mQueryDirection = newList.mQueryDirection
            }.build()
        }
    }
}

My Test

@RunWith(RobolectricTestRunner::class)
@Config(maxSdk = Build.VERSION_CODES.P, minSdk = Build.VERSION_CODES.P)
class ShopFilterValidatorTest {
    @get:Rule
    var instantExecutorRule = InstantTaskExecutorRule()

    private val context = InstrumentationRegistry.getInstrumentation().targetContext

    private lateinit var shopFilterValidator: ShopFilterValidator
    private lateinit var shopFilterDataStoreRepository: ShopFilterDataStoreRepository

    @Before
    fun setup() {
        shopFilterDataStoreRepository = ShopFilterDataStoreRepositoryImpl(context)
        shopFilterValidator = ShopFilterValidator(shopFilterDataStoreRepository)
    }

    @Test
    fun `test should start`() {

    }
}

Error Stacktrace

java.lang.ExceptionInInitializerError
    at androidx.datastore.core.DataStoreFactory.create(DataStoreFactory.kt:66)
    at androidx.datastore.DataStoreFactoryKt.createDataStore(DataStoreFactory.kt:58)
    at androidx.datastore.DataStoreFactoryKt.createDataStore$default(DataStoreFactory.kt:56)
    at com.example.app.framework.datasource.repository.shop.filter.ShopFilterDataStoreRepositoryImpl.<init>(ShopFilterDataStoreRepositoryImpl.kt:28)
    at com.example.app.validator.ShopFilterValidatorTest.setup(ShopFilterValidatorTest.kt:30)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:59)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:56)
    at org.junit.internal.runners.statements.RunBefores.invokeMethod(RunBefores.java:33)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:24)
    at org.junit.rules.TestWatcher$1.evaluate(TestWatcher.java:61)
    at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
    at org.robolectric.RobolectricTestRunner$HelperTestRunner$1.evaluate(RobolectricTestRunner.java:575)
    at org.robolectric.internal.SandboxTestRunner$2.lambda$evaluate$0(SandboxTestRunner.java:263)
    at org.robolectric.internal.bytecode.Sandbox.lambda$runOnMainThread$0(Sandbox.java:89)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
    at org.robolectric.internal.bytecode.ShadowWrangler.classInitializing(ShadowWrangler.java:166)
    at org.robolectric.internal.bytecode.RobolectricInternals.classInitializing(RobolectricInternals.java:21)
    at androidx.datastore.core.DataMigrationInitializer.<clinit>(DataMigrationInitializer.kt)
    at androidx.datastore.core.DataStoreFactory.$$robo$$androidx_datastore_core_DataStoreFactory$create(DataStoreFactory.kt:66)
    at androidx.datastore.core.DataStoreFactory.create(DataStoreFactory.kt)
    at androidx.datastore.DataStoreFactoryKt.$$robo$$androidx_datastore_DataStoreFactoryKt$createDataStore(DataStoreFactory.kt:58)
    at androidx.datastore.DataStoreFactoryKt.createDataStore(DataStoreFactory.kt)
    at androidx.datastore.DataStoreFactoryKt.createDataStore$default(DataStoreFactory.kt:56)
    at com.example.app.framework.datasource.repository.shop.filter.ShopFilterDataStoreRepositoryImpl.<init>(ShopFilterDataStoreRepositoryImpl.kt:28)
    at com.example.app.validator.ShopFilterValidatorTest.setup(ShopFilterValidatorTest.kt:30)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    ... 14 more
Caused by: java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.robolectric.internal.bytecode.RobolectricInternals.performStaticInitialization(RobolectricInternals.java:61)
    at org.robolectric.internal.bytecode.ShadowWrangler.classInitializing(ShadowWrangler.java:163)
    ... 27 more
Caused by: java.lang.BootstrapMethodError: java.lang.IllegalAccessError: tried to access class kotlin.jvm.internal.DefaultConstructorMarker from class androidx.datastore.core.DataMigrationInitializer$Companion
    at androidx.datastore.core.DataMigrationInitializer$Companion.<init>(DataMigrationInitializer.kt)
    at androidx.datastore.core.DataMigrationInitializer.__staticInitializer__(DataMigrationInitializer.kt)
    ... 33 more
Caused by: java.lang.IllegalAccessError: tried to access class kotlin.jvm.internal.DefaultConstructorMarker from class androidx.datastore.core.DataMigrationInitializer$Companion
    ... 35 more

Answer 1

Two options :

1. Either upgrade to Robolectric 4.5 (this is what you are missing: https://github.com/robolectric/robolectric/commit/e529de42f38cd2372eeb459b1a7c53139d2c754b)

2. Or, override RobolectricTestRunner and manually add androidx.datastore to the packages to not instrument :

   class DataStoreRobolectricTestRunner : RobolectricTestRunner {
   
       constructor(testClass: Class<*>) : super(testClass) {}
   
       constructor(testClass: Class<*>, injector: Injector) : super(testClass, injector) {}
   
       override fun createClassLoaderConfig(method: FrameworkMethod?): InstrumentationConfiguration {
           val parentClassLoaderConfig = super.createClassLoaderConfig(method)
           val builder = InstrumentationConfiguration.Builder(parentClassLoaderConfig)
   
           builder.doNotInstrumentPackage("androidx.datastore")
   
           return builder.build()
       }
   }