RSpec

If the database is abnormal, just run the following rakes to have a clean test database

bundle exec rake db:drop RAILS_ENV=test
bundle exec rake db:create RAILS_ENV=test

Set private instance variable

object.instance_variable_set(:@var, AnyValue)

Reference

• Rails 4 Resetting Test Database
• RSpec Practices
• Structure of RSpec tests
• 9 ways to speed up your RSpec tests
• Expecting Arguments
• How to set private instance variable used within a method test?
• Overriding global ordering