Redis database is same in development and test

Sidekiq uses Redis to store its queues. By default, in tests, it uses a memory representation instead: no Redis required.

However, it's sometimes necessary to disable the test implementation and call out to Redis: gitlab!25998 (comment 294675215)

When this happens, we're using the same Redis database for the test and development environments, so test runs interfere with (and read from) the queues in development mode. This can be very confusing. To take the linked example: by calling Sidekiq::Queue.new('authorized_projects').clear in a test, this will wipe any jobs in that queue created from the development UI, too.