What is [fixture_builder][1] ? Fixture Builder creates fixtures based on your definitions of [FactoryGirl][2] Why fixture_builder ? In projects with huge test suite, its possible that the creation of AR objects hinders the test performance. So to gain performance, we can avoid the redundant database transaction by building subsequent fixtures. Examples https://github.com/rdy/fixture_builder#example It gives tremendous boost to your test execution time. For us the statistics for 550 test cases were : Before fixture_builder ~ 2.5 hours After fixture_builder ~ 19.37 minutes Note : This should be backed up by proper [DatabaseCleaner][3]