If you need Sidekiq on Travis CI then you only need to do two things, start Redis and Sidekiq. Travis has build-in support for installing and starting Redis. You must add your own script to start Sidekiq.

An example .travis.yml

language: ruby
before_script:
  - bundle exec sidekiq -d -r ./spec/dummy_app/app.rb -L /tmp/sidekiq.log
  - sleep 1
services:
  - redis-server
rvm:
  - jruby-19mode
  - rbx-2
  - 2.0.0
  - 2.1
  - 2.2

If you target JRuby then you can’t use -d (detach) option to start sidekiq since JRuby does not support forking. Instead you can run the command in the background with &, i.e. bundle exec sidekiq -r ./spec/dummy_app/app.rb -L /tmp/sidekiq.log &.