public async Task Get_retrieves_buckets_with_requested_idsAsync() { //Arrange var id1 = 42; var id2 = 27; var bucket1 = new FileStoredBucket { Id = id1 }; var bucket2 = new FileStoredBucket { Id = id2 }; var bucket3 = new FileStoredBucket { Id = 123 }; var storagefolder = new Mock <IStorageFolder <FileStoredBucket> >(); storagefolder .Setup(fake => fake.GetStoredItemsAsync()) .Returns(MakeAsync(new[] { bucket1, bucket2, bucket3 })); var folderprovider = new Mock <IStorageFolderProvider>(); folderprovider .Setup(fake => fake.GetStorageFolder <FileStoredBucket>(It.IsAny <string>())) .Returns(storagefolder.Object); var storyStore = new Mock <IDataStore <Story> >(); var datastore = new InMemoryFileBackedBucketDataStore(folderprovider.Object, storyStore.Object); await datastore.InitializeAsync(); //Act var result = datastore.GetAsync(new[] { id1, id2 }).Result; //Assert var containsBucket1 = result.Any(b => b.Id == id1); var containsBucket2 = result.Any(b => b.Id == id2); Assert.IsTrue(containsBucket1); Assert.IsTrue(containsBucket2); Assert.AreEqual(2, result.Count()); }