Question

I got a problem with Moq and Automapper regarding IDataReader.
I found an example on stackoverflow and modified the code.

   public static IDataReader MockIDataReader<T>(List<T> ojectsToEmulate) where T : class
    {
        var moq = new Mock<IDataReader>();

        // This var stores current position in 'ojectsToEmulate' list
        var count = 0;

        moq.Setup(x => x.Read())
            // Return 'True' while list still has an item
            .Returns(() => count < ojectsToEmulate.Count)
            // Go to next position
            .Callback(() => count++);

        var properties = typeof (T).GetProperties();
        foreach (PropertyInfo t in properties)
        {
            var propName = t.Name;
            moq.Setup(x => x[propName]).Returns(() => ojectsToEmulate[count].GetType().GetProperty(propName).GetValue(ojectsToEmulate[count],null));
        }
        return moq.Object;
    }
}

My mapping:

Mapper.Configuration.CreateMap(typeof(IDataReader), typeof(IEnumerable<T>));
var result = Mapper.Map<IDataReader, IEnumerable<T>>(reader);

The problem I got here is that my result has 1 result a cityModel but all it’s properties are null. If I check the value from my mocked reader like reader[“name”] I got the “Alingsås” value so the mocking is correct but Automapper seams to have the problem.
I use a List of objects that I pass to my method that mocks it all.

var cityModel = new CityModel();
cityModel.Name = "Alingsås";
cityModel.Id = "SE";
cityModel.CountryId = "SE";

var cityModels = new List<CityModel>();
cityModels.Add(cityModel);

 _fakeReader = MockTester.MockIDataReader(cityModels);

The code works fine, no exception is thrown, but the mapper gives me an object without the
valules. I can see in the debugger my reflection code works but it seams like my
x[“Name”] aren’t the method Automapper call from IDataReader? Or is it?

What can be wrong here?

Answer 1

Automapper internally uses the int indexer of IDataReader so you need to call Setup on that instead of Item[String].

Checking the Automapper’s source you need to setup some additional methods to make it work:

//...
var index = 0;
foreach (PropertyInfo t in properties)
{
    var propName = t.Name;
    int index1 = index; // avoid access to modified closure
    moq.Setup(x => x.GetFieldType(index1)).Returns(t.PropertyType);
    moq.Setup(x => x.GetName(index1)).Returns(propName);
    moq.Setup(x => x[index1])
        .Returns(ojectsToEmulate[count]
                 .GetType()
                 .GetProperty(propName).GetValue(ojectsToEmulate[count], null));
    index++;
}

moq.Setup(x => x.FieldCount).Returns(properties.Length);
//...