Adding more unit tests. Fixing Salmon slaps XML

app/helpers/atom_builder_helper.rb

app/services/favourite_service.rb

app/services/fetch_atom_service.rb

app/services/unfavourite_service.rb

app/workers/after_remote_follow_request_worker.rb

app/workers/after_remote_follow_worker.rb

spec/services/authorize_follow_service_spec.rb

spec/services/block_service_spec.rb

spec/services/favourite_service_spec.rb

spec/services/follow_service_spec.rb

spec/services/reject_follow_service_spec.rb

spec/services/unblock_service_spec.rb

spec/services/unfollow_service_spec.rb