Fixes pretty big issue with MediaType's not implementing the same IsDirty property check rules as ContentType when they should have shared the same rules. After removing caching on the unit tests, this bug became known.

src/Umbraco.Tests/Persistence/Repositories/ScriptRepositoryTest.cs

@@ -24,14 +24,14 @@ namespace Umbraco.Tests.Persistence.Repositories
         }
 
         [Test]
-        public void Can_Instantiate_Repository_From_Resolver()
+        public void Can_Instantiate_Repository()
         {
             // Arrange
             var provider = new FileUnitOfWorkProvider();
             var unitOfWork = provider.GetUnitOfWork();
 
             // Act
-            var repository = RepositoryResolver.Current.ResolveByType<IScriptRepository>(unitOfWork);  
+            var repository = new ScriptRepository(unitOfWork, _fileSystem);
 
             // Assert
             Assert.That(repository, Is.Not.Null);