public async void UnitId_Create_Valid_Reference()
        {
            Mock <ICallAssignmentRepository> callAssignmentRepository = new Mock <ICallAssignmentRepository>();

            callAssignmentRepository.Setup(x => x.UnitByUnitId(It.IsAny <int>())).Returns(Task.FromResult <Unit>(new Unit()));

            var validator = new ApiCallAssignmentServerRequestModelValidator(callAssignmentRepository.Object);
            await validator.ValidateCreateAsync(new ApiCallAssignmentServerRequestModel());

            validator.ShouldNotHaveValidationErrorFor(x => x.UnitId, 1);
        }
        public async void CallId_Update_Valid_Reference()
        {
            Mock <ICallAssignmentRepository> callAssignmentRepository = new Mock <ICallAssignmentRepository>();

            callAssignmentRepository.Setup(x => x.CallByCallId(It.IsAny <int>())).Returns(Task.FromResult <Call>(new Call()));

            var validator = new ApiCallAssignmentServerRequestModelValidator(callAssignmentRepository.Object);
            await validator.ValidateUpdateAsync(default(int), new ApiCallAssignmentServerRequestModel());

            validator.ShouldNotHaveValidationErrorFor(x => x.CallId, 1);
        }