Mock glide fetcher

GlideExtensions.kt

inline fun <reified T : Key> Glide.registerMockStreamModelLoader() = registerMockStreamModelLoader(T::class.java)

fun <T : Key> Glide.registerMockStreamModelLoader(modelClass: Class<T>) {
    val modelLoaderFactory: ModelLoaderFactory<T, InputStream> = mock()
    val modelLoader = mockStreamModelLoader(modelClass)
    whenever(modelLoaderFactory.build(any())).thenReturn(modelLoader)

    this.registry.append(modelClass, InputStream::class.java, modelLoaderFactory)
}

private fun <T : Key> mockStreamModelLoader(modelClass: Class<T>): ModelLoader<T, InputStream> {
    val modelLoader: ModelLoader<T, InputStream> = mock()
    val fetcher: DataFetcher<InputStream> = mock()

    doAnswer { invocation ->
        val callback: DataFetcher.DataCallback<InputStream> = invocation.getArgument(1)
        callback.onDataReady(ByteArrayInputStream(ByteArray(0)))
    }.whenever(fetcher).loadData(any(), any())

    doAnswer { invocation ->
        val obj: T = invocation.getArgument(0)
        ModelLoader.LoadData(obj, fetcher)
    }.whenever(modelLoader).buildLoadData(Mockito.any(modelClass), anyInt(), anyInt(), any())

    return modelLoader
}