Add unit tests for AvatarServiceRegistry.for_user

Review Request #8247 — Created June 17, 2016 and submitted — Latest diff uploaded

Information

Djblets
release-0.10.x
5b9fd1a...

Reviewers

The most recent patch for avatar service registries removed the
get_or_default method in favour of the for_user method. This patch
removes the tests for the old method and adds tests for the new method.

Ran unit tests.