ChangeTracking.Tests.IChangeTrackableCollectionTests.RejectChanges_On_Collection_Should_RejectChanges C# (CSharp) Method

        public void RejectChanges_On_Collection_Should_RejectChanges()
        {
            var orders = Helper.GetOrdersIList();
            var trackable = orders.AsTrackable();

            var first = trackable.First();
            first.Id = 963;
            first.CustomerNumber = "Testing";
            var newOrder = Helper.GetOrder();
            newOrder.Id = 999;
            trackable.Add(newOrder);
            trackable.RemoveAt(5);
            var intf = trackable.CastToIChangeTrackableCollection();
            intf.RejectChanges();
            var ordersToMatch = Helper.GetOrdersIList().AsTrackable();

            intf.UnchangedItems.Should().Contain(i => ordersToMatch.SingleOrDefault(o =>
                o.Id == i.Id &&
                i.CustomerNumber == o.CustomerNumber &&
                i.CastToIChangeTrackable().ChangeTrackingStatus == o.CastToIChangeTrackable().ChangeTrackingStatus) != null);
            intf.UnchangedItems.Count().Should().Be(ordersToMatch.Count);
            intf.UnchangedItems.Count().Should().Be(intf.Count());
        }