Automatically reload test databases on migration

[dankohn]

parlallel_tests, while amazing, doesn't support the Rails 4 feature of automatically reloading the test databases after migration. The following works for me, though it's not elegant:

#lib/tasks/custom.rake
namespace :custom do
  desc "Reset test database"
  task test_reset: :environment do
    sh 'RAILS_ENV=test rake parallel:load_schema'
  end

  desc "Hard reset test database"
  task test_reset_hard: :environment do
    sh 'rake custom:pg_terminate RAILS_ENV=test parallel:drop parallel:create parallel:load_schema'
  end

  desc "Prepare test database"
  task parallel_prepare: :environment do
    sh 'RAILS_ENV=test rake custom:parallel_prepare_complete'
  end

  desc "Finish preparing test databases"
  task parallel_prepare_complete: :environment do
    if ActiveRecord::Base.maintain_test_schema && ActiveRecord::Migrator.needs_migration?
      puts 'Loading schema.rb into each of the parallel test databases'
      Rake::Task['parallel:load_schema'].reenable
      Rake::Task['parallel:load_schema'].invoke
    end
  end

  desc "Show if test migration needed"
  task test_migration_needed: :environment do
    command = %q{RAILS_ENV=test rails runner 'puts "#{ActiveRecord::Migrator.needs_migration?}"'}
    sh command
  end

  desc "Terminate Postgres users to enable db:drop"
  task pg_terminate: :environment do
    sh "echo 'SELECT pg_terminate_backend(pg_stat_activity.pid) FROM pg_stat_activity WHERE datname = current_database() AND pg_stat_activity.pid <> pg_backend_pid();' | rails db"
  end
end

Then replace ActiveRecord::Migration.maintain_test_schema! in spec/rails_helper.rb:

if ActiveRecord::Base.maintain_test_schema && ActiveRecord::Migrator.needs_migration?
  require 'rake'
  Chewy::Application.load_tasks
  Rake::Task['parallel:load_schema'].invoke
end

And redefine the default task in `lib/tasks/default.rake:

task(:default).clear.enhance ['custom:parallel_prepare', 'parallel:spec','parallel:features']

I'd be happy to add these as a pull request, but others can probably suggest a less hacky solution. This is a good overview of changing RAILS_ENV in rake tasks.

[ronwsmith]

👍

[jeremywadsack]

As most of these just run a shell command, do you need them to load :environment? Seems like removing that dependency would make them much faster. Especially as the shell command then reloads the Rails environment under test.