Displays a KeyError. Research must be done to find out why/fix this issue.
Figured out how to solve the test case.
Currently the django team gives us "inner_formset = response.context[-1]['inline_admin_formsets'].formset" and removing the [-1] makes Django find the 'inline_admin_formsets'. However this goes against our goal of not touching the test case code (maybe this is a bug in the 2.x code?).
Future development: find out if I've fixed a bug in 2.x, problem solved; else find out why it fails only in 3.0. It does not seem Python 3.0's changes are at fault.