public void Receive_Message_Transactional_Will_Throw_A_Not_Implemented_Exception() { //Arrange var mockBytes = new byte[] { 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33 }; var mockTransaction = new Mock <ITransaction>(); var listener = new ServiceBusListener(_mockSerialiser.Object, _mockHandlerResolver.Object, _mockHandlerInvoker.Object); //Act async Task Delegate() { await listener.ReceiveMessageTransactional(mockBytes, mockTransaction.Object, CancellationToken.None); } //Assert Assert.That(Delegate, Throws.TypeOf <NotImplementedException>()); }