public async Task AddMessageAsync()
{
var mockRepo = new Mock <IDeletableEntityRepository <Message> >();
mockRepo.Setup(x => x.AddAsync(It.IsAny <Message>())).Callback(
(Message mess) => this.messages.Add(mess));
var service = new MessagesService(mockRepo.Object);
await service.AddMessageAssyns("d34", "ABC");
Assert.Equal(4, this.messages.Count);
}