These tests cover the RunTool and update_tools_list tasks, with all

possible success and error conditions, helping ensure we don't break

this code path as we iterate on code.
Celery tasks can be somewhat tricky to test, as there isn't a standard

way of doing this, but in our case it's not too difficult. For

RunTool, We just needed to hijack part of the process to inject a

custom delivery_info with the routing key that maps to the tool to

run.
These tests work on Celery 3.x (Python 2.7) and 4.x (Python 3).
Since much of these task code paths involve talking to the API, this

change also provides a bunch of stubbed-out resources that either do

nothing or chain to other resoureces that we can spy on.

Unit tests pass for Python 2.7 and 3.x, on Celery 3.x and 4.x.