public async Task CopyAsync_Always_Throws() { var destinationStorage = CreateNewFileStorage(); var sourceFileUri = _storage.ResolveUri("a"); var destinationFileUri = destinationStorage.ResolveUri("a"); await Assert.ThrowsAsync <NotImplementedException>( () => _storage.CopyAsync( sourceFileUri, destinationStorage, destinationFileUri, destinationProperties: null, cancellationToken: CancellationToken.None)); }