       guard let data = data else { return nil }
       return try? NSKeyedUnarchiver.unarchiveTopLevelObjectWithData(data) as? NSArray
     }
-
+    
     let array = NSMutableArray()
     array.add(1)
     array.add(Color(name: "green"))

    Transformer<Dummy>.unregister()
    XCTAssertFalse(Foundation.ValueTransformer.valueTransformerNames().contains(DataTransformer<Dummy>.transformerName))
  }

  func testTransformer() throws {
    let transformer = Transformer<Color>()
    let data = transformer.reverseTransformedValue(Color(name: "green"))

    car.color = Color(name: "red")
    try context.save()
    context.reset()
    
    let firstCar = try XCTUnwrap(try Car.fetchOne(in: context, where: NSPredicate(value: true)))
    
    let color = try XCTUnwrap(firstCar.color)
    XCTAssertEqual(color.name, "red")
  }
  
  func testSaveAndFetchTransformableValueUsingCustomTransformer() throws {
    let context = container.viewContext
    let car = Car(context: context)
