Currently, unit tests for the scheduler involve a lot of different mocks. This complicates the tests, and reduces the amount of code that is actually tested (e.g. the database queries aren't tested). Instead of this, a similar approach should be taken as the frontend, where an "in memory" SQLite database is used with staged content to test functionality. Ideally, the only mocks needed in the scheduler's tests should be Koji (and other builders).