To fix your unit tests to "wait" until your data is loaded by your loadDevelopers method, you need to have your setUp method return the Deferred created by loadDevelopers's. There are a bunch of ways to do this, the simplest is probably to have your factory's __init__ method store the
Deferred created by loadDevelopers into a member variable (say self.deferred), and then add a new line to the end of your setUp method above:

return self.deferred

This way, each unit test will not start until the Deferred from loadDevelopers fires.

That worked! I was so close to this over the weekend too. I'm starting to feel as though I need an MIT degree to understand this stuff. :)

Brendon