public async void LessonStatusId_Update_Valid_Reference()
        {
            Mock <ILessonRepository> lessonRepository = new Mock <ILessonRepository>();

            lessonRepository.Setup(x => x.GetLessonStatus(It.IsAny <int>())).Returns(Task.FromResult <LessonStatus>(new LessonStatus()));

            var validator = new ApiLessonRequestModelValidator(lessonRepository.Object);
            await validator.ValidateUpdateAsync(default(int), new ApiLessonRequestModel());

            validator.ShouldNotHaveValidationErrorFor(x => x.LessonStatusId, 1);
        }
        public async void StudioId_Update_Invalid_Reference()
        {
            Mock <ILessonRepository> lessonRepository = new Mock <ILessonRepository>();

            lessonRepository.Setup(x => x.GetStudio(It.IsAny <int>())).Returns(Task.FromResult <Studio>(null));

            var validator = new ApiLessonRequestModelValidator(lessonRepository.Object);

            await validator.ValidateUpdateAsync(default(int), new ApiLessonRequestModel());

            validator.ShouldHaveValidationErrorFor(x => x.StudioId, 1);
        }