@CustomTestApplication value cannot be annotated with @HiltAndroidApp

I have an application that needs injection:

@HiltAndroidApp
class MyApplication: Application() {
    @Inject lateinit var printerFactory: PrinterFactory
    ...
}

Other code in the app uses application.printerFactory.

The printerFactory is provided by this:

@Module
@InstallIn(ApplicationComponent::class)
object ProdModule {
    @Provides
    fun providePrinterFactory(): PrinterFactory {
        return FactoryThatReturnsARealPrinter()
    }
}

Now, for instrumented tests, I need to override this with a test version:

@HiltAndroidTest
@UninstallModules(ProdModule::class)
@RunWith(AndroidJUnit4::class)
@LargeTest
class MainTest {
    @get:Rule(order = 0)
    var hiltRule = HiltAndroidRule(this)

    @get:Rule(order = 1)
    var intentsTestRule = IntentsTestRule(MainActivity::class.java, false, false)

    // Test replacements for production stuff.
    @Module
    @InstallIn(ApplicationComponent::class)
    class TestModule {
        @Provides
        fun providePrinterFactory(): PrinterFactory {
            return FactoryThatReturnsATestPrinter()
        }
    }
    ...
}

And so I get this error:

java.lang.IllegalStateException: Hilt test, MainTest, cannot use a @HiltAndroidApp application but found MyApplication. To fix, configure the test to use HiltTestApplication or a custom Hilt test application generated with @CustomTestApplication.

Well, I can’t use HiltTestApplication because I need to use MyApplication, which has dependencies injected.

So I added this:

    @CustomTestApplication(MyApplication::class)
    interface HiltTestApplication

And so I get this error:

error: [Hilt]
    public static abstract interface HiltTestApplication {
                           ^
  @CustomTestApplication value cannot be annotated with @HiltAndroidApp. Found: MyApplication

If MyApplication cannot be annotated with @HiltAndroidApp, then how is it expected to inject things?

Instructions unclear, ended up in inconsistent state.

[rhonyabdullah]

Bad Solution Regarding the this documentation I create interface and put my test application:

@CustomTestApplication(TestApplication::class)
interface AndroidTestApplication

But it gives me exception:

Caused by: java.lang.InstantiationException: java.lang.Class<com.myapp.AndroidTestApplication> cannot be instantiated
        at java.lang.Class.newInstance(Native Method)
        at android.app.Instrumentation.newApplication(Instrumentation.java:1165)
        at com.myapp..AndroidTestRunner.newApplication(AndroidTestRunner.kt:16)
        at android.app.LoadedApk.makeApplication(LoadedApk.java:1218)

So i’m directly passing the generated hilt application class for my test app and skip using AndroidTestApplication interface and it works: Instrumentation.newApplication(AndroidTestApplication_Application::class.java, context)

[tianjyan]

@danysantiago I got the following issue when I use a base app. Do I missing something else ?

java.lang.RuntimeException: Unable to instantiate application com.sample.MainApplication: java.lang.InstantiationException: java.lang.Class<com.sample.di.TestApplication> cannot be instantiated

@CustomTestApplication(BaseApplication::class)
interface TestApplication

open class BaseApplication : Application()

@HiltAndroidApp
open class MainApplication : BaseApplication()