appraisal install
This will re-generate Gemfiles in gemfile
folder
Use rvm gemsets or similar to avoid global gem pollution
For all supported Rails/ORM combinations:
appraisal rspec
Or for specific one:
appraisal rails_4.2 rspec
Or for one particular test file
appraisal rails_4.2_mongoid_5 rspec spec/unit/persistence/mongoid_persistence_multiple_spec.rb
Or down to one test case
appraisal rails_4.2_mongoid_5 rspec spec/unit/persistence/mongoid_persistence_multiple_spec.rb:92