class App: Application(), DependencyModulesHolder {
    override val dependencyModules: DependencyModules by dependencyModules(AppModule(this), CoroutinesModule())
}

open class CoroutinesModule : DependencyModule {
    open val defaultDispatcher: CoroutineDispatcher = Dispatchers.Default
    open val ioDispatcher: CoroutineDispatcher = Dispatchers.IO
    open val mainDispatcher: CoroutineDispatcher = Dispatchers.Main
    open val mainImmediateDispatcher: CoroutineDispatcher = Dispatchers.Main.immediate
}

class AppModule(private val application: Application) : DependencyModule {
    private val coroutinesModule: CoroutinesModule by lazy {
        application.dependencyModule<CoroutinesModule>()
    }
    val loadItemsUseCase: LoadItemsUseCase
        get() = LoadItemsUseCase(coroutineModule.ioDispatcher)
}

class MainActivity : AppCompatActivity() {
    private val loadItemsUseCase by dependency<AppModule, LoadItemsUseCase> { it.loadItemsUseCase }
}

class MainActivity : AppCompatActivity() {
    private val loadItemsUseCase: LoadItemsUseCase by lazy { dependencyModule<AppModule>().loadItemsUseCase }
}

class MainViewModel @JvmOverloads constructor(
    application: Application,
    savedStateHandle: SavedStateHandle
    private val loadItemsUseCase: LoadItemsUseCase = application.dependencyModule<AppModule>().loadItemsUseCase
) : AndroidViewModel(application) {
    // You can use loadItemsUseCase
}

@Test
fun test() {
    // init loadItemsUseCase
    // ...
    // init ViewModel
    val viewModel = MainViewModel(Application(), SavedStateHandle(), loadItemsUseCase)
    // test ViewModel
}

class CustomTestRunner : AndroidJUnitRunner() {
    override fun newApplication(cl: ClassLoader?, name: String?, context: Context?): Application {
        return super.newApplication(cl, TestApp::class.java.name, context)
    }
}

class TestApp: Application(), DependencyModulesHolder {
    override val dependencyModules: DependencyModules by dependencyModules(AppModule(this), TestCoroutinesModule())
}

class TestCoroutinesModule : CoroutinesModule() {
    override val defaultDispatcher: CoroutineDispatcher = AsyncTask.THREAD_POOL_EXECUTOR.asCoroutineDispatcher()
    override val ioDispatcher: CoroutineDispatcher = AsyncTask.THREAD_POOL_EXECUTOR.asCoroutineDispatcher()
    override val mainDispatcher: CoroutineDispatcher = Dispatchers.Main
    override val mainImmediateDispatcher: CoroutineDispatcher = Dispatchers.Main.immediate
}

class App: Application(), DependencyModulesHolder {
    override val dependencyModules: DependencyModules by dependencyModules(AppModule(this), CoroutinesModule())
}

val Application.dependencyModules: DependencyModules
    get() = (this as DependencyModulesHolder).dependencyModules
val FragmentActivity.dependencyModules: DependencyModules
    get() = application.dependencyModules
val Fragment.dependencyModules: DependencyModules
    get() = requireActivity().application.dependencyModules
val AndroidViewModel.dependencyModules: DependencyModules
    get() = getApplication<Application>().dependencyModules
val Service.dependencyModules: DependencyModules
    get() = application.dependencyModules
val Context.dependencyModules: DependencyModules
    get() = (applicationContext as Application).dependencyModules

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        dependencyModules.addModule(DynamicModule()) // add only once
    }
}

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        // Replace an existing DependencyModule of the same type with a new DependencyModule
        dependencyModules.replaceModule(AppModule(application))
    }
}