title: swift Xcode unit test: Cannot convert value of type "Person" to expected argument type "Person"
body: <p>I am trying to write a unit test class to test my custom classes. When I am trying to call a method in the custom class with a custom object as the input variable, I got:
  'Cannot convert value of type "Person"  to expected argument type "Person". "Person" is the class, inherited from NSManagedObject, where the input object was created from. I have no problem with other methods taking other value type. The method works fine. The test class is the only one complains this. Is it a bug or limitation? Any suggestion I can dig deeper on this issue?</p>