Enabling mapping from interfaces, re: issue #11

Author: SteveWilkes

AgileMapper.UnitTests/AgileMapper.UnitTests.csproj

@@ -81,6 +81,7 @@
     <Compile Include="Dictionaries\Configuration\WhenConfiguringNestedDictionaryMapping.cs" />
     <Compile Include="Dictionaries\Configuration\WhenConfiguringTargetDictionaryMapping.cs" />
     <Compile Include="Dictionaries\WhenCreatingRootDictionaryMembers.cs" />
+    <Compile Include="TestClasses\IPublicInterface.cs" />
     <Compile Include="TestClasses\MegaProduct.cs" />
     <Compile Include="TestClasses\ProductDto.cs" />
     <Compile Include="TestClasses\ProductDtoMega.cs" />
@@ -115,6 +116,7 @@
     <Compile Include="TestClasses\PaymentTypeUk.cs" />
     <Compile Include="TestClasses\PaymentTypeUs.cs" />
     <Compile Include="TestClasses\PublicFactoryMethod.cs" />
+    <Compile Include="TestClasses\PublicImplementation.cs" />
     <Compile Include="TestClasses\PublicSealed.cs" />
     <Compile Include="TestClasses\PublicTwoFields.cs" />
     <Compile Include="TestClasses\PublicTwoParamCtor.cs" />

AgileMapper.UnitTests/TestClasses/IPublicInterface.cs

@@ -0,0 +1,7 @@
+namespace AgileObjects.AgileMapper.UnitTests.TestClasses
+{
+    public interface IPublicInterface<T>
+    {
+        T Value { get; set; }
+    }
+}

AgileMapper.UnitTests/TestClasses/PublicImplementation.cs

@@ -0,0 +1,7 @@
+namespace AgileObjects.AgileMapper.UnitTests.TestClasses
+{
+    public class PublicImplementation<T> : IPublicInterface<T>
+    {
+        public T Value { get; set; }
+    }
+}

AgileMapper.UnitTests/WhenMappingToNewComplexTypes.cs

@@ -71,5 +71,19 @@ public void ShouldMapFromASimpleTypeToObject()
 
             result.Value.ShouldBe("Oi 'Arold!");
         }
+
+        // See https://github.com/agileobjects/AgileMapper/issues/11
+        [Fact]
+        public void ShouldMapFromAnInterface()
+        {
+            IPublicInterface<string> source = new PublicImplementation<string>
+            {
+                Value = "Interfaces!"
+            };
+
+            var result = Mapper.Map(source).ToANew<PublicField<string>>();
+
+            result.Value.ShouldBe("Interfaces!");
+        }
     }
 }

AgileMapper/Configuration/DerivedTypePairSet.cs

@@ -239,6 +239,11 @@ private static bool SkipDerivedTypePairsLookup(
 
         private static Type GetRootType(Type type)
         {
+            if (type.IsInterface)
+            {
+                return type;
+            }
+
             var parentType = type;
 
             while (parentType != typeof(object))