Copy over the relevant tests from the Gravity module

[evan-forbes]

Over the course of a few PRs (#208, #212, #215, #218) we've moved and adapted the relevant portions of logic over from the gravity module into the qgb module (on the qgb integration branch).

However, we still need to perform the same treatment to all the relevant unit tests for both business logic and queries. While this may be a bit redundant at first, whenever we introduce any future modifications, this will become absolutely necessary.

We need tests for each method added to the qgb keeper, and we might even want to consider grabbing some of the integration tests too

[evan-forbes]

closed by #237