Mock DataServiceQuery

[Javier]

Hi,

I am trying to Mock a Data Service Context based on WCF Data Services, here is the code of the DataService

using System.Data.Services.Client;
using Tgw.Wcs.Windows.Data.UIModel;

namespace Tgw.Wcs.Windows.DataServices
{
    public partial class ClientDataModelServiceContext
    {

        public DataServiceQuery<LoadCarrier> GetLoadCarrier()
        {
            if ((this.GetLoadCarrierSet == null))
            {
                this.GetLoadCarrierSet = base.CreateQuery<LoadCarrier>("GetLoadCarriers");
            }
            return this.GetLoadCarrierSet;
        }
    }
}

What I would like is to Mock this class in order to get a List of LoadCarriers, We can get this list if we execute GetLoadCarrier().Execute() which returns a IEnumerable<LoadCarrier>

This is the class I am trying to test:

public class LoadCarrierRepository : ILoadCarrierRepository
    {
        private ClientDataModelServiceContext dataContext;

        public ClientDataModelServiceContext DataContext
        {
            get
            {
                if (dataContext == null)
                {
                    var uri = WcsEndpointUriUtility.ClientDataQueryServiceAddress;
                    dataContext = new ClientDataModelServiceContext(uri);
                }
                return dataContext;
            }
        }

        [Dependency]
        public WcsEndpointUriUtility WcsEndpointUriUtility { get; set; }

        public IQueryable<LoadCarrier> GetLoadCarriers()
        {
            DataServiceQuery<LoadCarrier> loadCarriers = DataContext.GetLoadCarrier().Expand(x=>x.ContainerType).Expand(x=>x.ContainerType.AttributeView).Expand(x=>x.BookedInventoryAccount).Expand(x=>x.Location).Expand(x=>x.Location.StructureLeaf.WarehouseGeometry).Expand(x => x.EntityLocks).Expand(x=>x.AttributeView);

            return loadCarriers;
        }
    }

And this is the test:

/// <summary>
        /// We will test
        /// </summary>
        [TestMethod]
        public void GetLoadCarrierFromDataContextHasData()
        {
            LoadCarrierRepository loadCarrierRepository = new LoadCarrierRepository();
            loadCarrierRepository.WcsEndpointUriUtility = Mock.Create<WcsEndpointUriUtility>();

            Mock.Arrange(() => loadCarrierRepository.DataContext.GetLoadCarrier().Execute()).ReturnsCollection(new List<LoadCarrier>(new List<LoadCarrier>()));
            //Mock.Arrange(() => loadCarrierRepository.GetLoadCarriers()).ReturnsCollection(new List<LoadCarrier>(){new LoadCarrier()});

            var loadCarriers = loadCarrierRepository.GetLoadCarriers();

            Assert.IsTrue(loadCarriers != null);
            Assert.AreEqual(1, loadCarriers.Count());

        }
I am getting the following exception:

Test method Tgw.Wcs.Windows.Test.U.ComponentTests.Modules.LoadCarriers.LoadCarrierRepositoryTest.GetLoadCarrierFromDataContextHasData threw exception: 
System.ArgumentNullException: Value cannot be null.
Parameter name: expression
    at System.Linq.Expressions.Expression.RequiresCanRead(Expression expression, String paramName)
   at System.Linq.Expressions.Expression.Convert(Expression expression, Type type, MethodInfo method)
   at System.Linq.Expressions.Expression.Convert(Expression expression, Type type)
   at System.Data.Services.Client.DataServiceQuery`1.Expand(Expression`1 navigationPropertyAccessor)
   at Tgw.Wcs.Windows.Module.LoadCarriers.Repository.LoadCarrierRepository.GetLoadCarriers() in LoadCarrierRepository.cs: line 34
   at Tgw.Wcs.Windows.Test.U.ComponentTests.Modules.LoadCarriers.LoadCarrierRepositoryTest.GetLoadCarrierFromDataContextHasData() in LoadCarrierRepositoryTest.cs: line 39

[Kaloyan]

Hi Javier,

Thank you for the code provided.

I assume you will need to change the following arrange:

Mock.Arrange(() => loadCarrierRepository.DataContext.GetLoadCarrier().Execute()).ReturnsCollection(new List<LoadCarrier>(new List<LoadCarrier>()));

To something like this:

Mock.Arrange(() => loadCarrierRepository.DataContext.GetLoadCarrier()).ReturnsCollection(new List<LoadCarrier>(new List<LoadCarrier>()));

However, if this does not help, I will require a sample project, reproducing the issue in order to assist you further. Please, let me know if this is doable for you.

I hope this works.

Regards,
Kaloyan
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