Clean up campaigns/resolvers tests
Created by: mrnugget
This does a few small things:
- Remove a TODO in
TestApplyCampaignand replace it with actual assertion - Remove an unused test helper
- Move
TestChangeseCountsOverTimeto thecampaigns_test.gofile where the resolver is on which the method is defined - Move all test helpers into
main_test.goinstead oftesting.go