Add an exception for non interface registrations.

Author: hypercodeplace

LazyProxy.Unity.Tests/UnityExtensionTests.cs

@@ -275,5 +275,11 @@ public void ServicesMustBeResolvedByNameWithCorrectInjectionMembers()
             Assert.Equal("service1->" + result1, actualResult1);
             Assert.Equal("service1->" + result2, actualResult2);
         }
+
+        [Fact]
+        public void RegistrationMustThrowAnExceptionForNonInterfaces()
+        {
+            Assert.Throws<NotSupportedException>(() => new UnityContainer().RegisterLazy<Service1, Service1>());
+        }
     }
 }

LazyProxy.Unity/UnityExtensions.cs

@@ -73,6 +73,12 @@ public static IUnityContainer RegisterLazy<TFrom, TTo>(this IUnityContainer cont
             params InjectionMember[] injectionMembers)
             where TTo : TFrom where TFrom : class
         {
+            // There is no way to constraint it on the compilation step.
+            if (!typeof(TFrom).IsInterface)
+            {
+                throw new NotSupportedException("The lazy registration is supported only for interfaces.");
+            }
+
             var lazyProxyType = LazyProxyBuilder.BuildLazyProxyType<TFrom>();
             var registrationName = Guid.NewGuid().ToString();