title: Create a subclass from an instance to override a few methods?
body: <p>For testing purposes, I want to replace the implementation of a few methods of an object that implements some interface. One way of doing this would be to create a new object, passing the instance as a parameter to the constructor, and manually recreating all of the methods to use the instance's methods for all but a couple of methods, which would be overridden for testing purposes. Unfortunately, the interface has a large number of methods, which makes this option tedious.</p>
  
  <p>Is there some way to create an object that is a "subclass of an instance of an object" in the sense that it simply calls the instance's method's for all calls except when overridden?</p>