public void Get_IsDelivering_For_DistributionCenter()
        {
            var couriers = GetCouriers().AsQueryable();
            var center   = GetDistributionCenters().FirstOrDefault(c => c.Id == 1);

            var mockDbSet = new Mock <DbSet <Courier> >();

            mockDbSet.As <IQueryable <Courier> >().Setup(p => p.Provider).Returns(couriers.Provider);
            mockDbSet.As <IQueryable <Courier> >().Setup(p => p.Expression).Returns(couriers.Expression);
            mockDbSet.As <IQueryable <Courier> >().Setup(p => p.ElementType).Returns(couriers.ElementType);
            mockDbSet.As <IQueryable <Courier> >().Setup(p => p.GetEnumerator()).Returns(couriers.GetEnumerator);

            var mockContext = new Mock <RentalContext>();

            mockContext.Setup(r => r.Couriers).Returns(mockDbSet.Object);

            var service  = new DistributionService(mockContext.Object);
            var delivery = service.IsDelivering(center.Id);

            switch (DateTime.Now.DayOfWeek)
            {
            case DayOfWeek.Saturday:
                delivery.Should().BeTrue();
                break;

            case DayOfWeek.Sunday:
                delivery.Should().BeTrue();
                break;

            case DayOfWeek.Monday:
                delivery.Should().BeFalse();
                break;

            case DayOfWeek.Tuesday:
                delivery.Should().BeFalse();
                break;

            case DayOfWeek.Wednesday:
                delivery.Should().BeFalse();
                break;

            case DayOfWeek.Thursday:
                delivery.Should().BeFalse();
                break;

            case DayOfWeek.Friday:
                delivery.Should().BeFalse();
                break;

            default:
                delivery.Should().BeFalse();
                break;
            }
        }