Adding test; closes #89

src/UnitTests/InterfaceMapping.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.ComponentModel;
+using System.Linq;
 using Should;
 using NUnit.Framework;
 
@@ -359,6 +360,40 @@ public void Should_ignore_interface_members_for_validation()
             }
         }
 
+        public class MappingToInterfacesWithPolymorphism : AutoMapperSpecBase
+        {
+            private BaseDto[] _baseDtos;
+
+            public interface IBase { }
+            public interface IDerived : IBase { }
+            public class Base : IBase { }
+            public class Derived : Base, IDerived { }
+            public class BaseDto { }
+            public class DerivedDto : BaseDto { }
+
+            //and following mappings:
+            protected override void Establish_context()
+            {
+                Mapper.CreateMap<Base, BaseDto>().Include<Derived, DerivedDto>();
+                Mapper.CreateMap<Derived, DerivedDto>();
+                // try with and without the following two lines, also try with just the following two lines
+                Mapper.CreateMap<IBase, BaseDto>().Include<IDerived, DerivedDto>();
+                Mapper.CreateMap<IDerived, DerivedDto>();
+            }
+            protected override void Because_of()
+            {
+                List<Base> list = new List<Base>() { new Derived() };
+                _baseDtos = Mapper.Map<IEnumerable<Base>, BaseDto[]>(list);
+            }
+
+            [Test]
+            public void Should_use_the_derived_type_map()
+            {
+                _baseDtos.First().ShouldBeType<DerivedDto>();
+            }
+
+        }
+
         [TestFixture, Explicit]
         public class MappingToInterfacesPolymorphic
         {