With the API changes in RBTools 6, a few of the things we were doing for

mocking with unit tests were failing. There were two types of errors

being hit:

We now handle NotImplementedError for cases where an API payload

   does not contain a link, instead of just assuming that the method

   won't exist on the class. This is necessary because we now have API

   stubs present on the resource classes.
Always pass in a payload and token for ListResource instantiation.

Ran unit tests.