public async void ProjectId_Update_length()
        {
            Mock <IChannelRepository> channelRepository = new Mock <IChannelRepository>();

            channelRepository.Setup(x => x.Get(It.IsAny <string>())).Returns(Task.FromResult(new Channel()));

            var validator = new ApiChannelRequestModelValidator(channelRepository.Object);
            await validator.ValidateUpdateAsync(default(string), new ApiChannelRequestModel());

            validator.ShouldHaveValidationErrorFor(x => x.ProjectId, new string('A', 51));
        }
        private async void BeUniqueByNameProjectId_Update_Not_Exists()
        {
            Mock <IChannelRepository> channelRepository = new Mock <IChannelRepository>();

            channelRepository.Setup(x => x.ByNameProjectId(It.IsAny <string>(), It.IsAny <string>())).Returns(Task.FromResult <Channel>(null));
            var validator = new ApiChannelRequestModelValidator(channelRepository.Object);

            await validator.ValidateUpdateAsync(default(string), new ApiChannelRequestModel());

            validator.ShouldNotHaveValidationErrorFor(x => x.Name, "A");
        }