ConcurrentUnitTest __________________ ConcurrentUnitTest allows to run unit tests concurrently. Ruby interpreter does not use native threads, so if the unit tests are CPU bound then there is no need to run unit tests concurrently. If unit tests IO bound, especially if they write/read database, running them concurrently can dramatically speed up execution. If you use JRuby even running CPU bound tests may be beneficial, because JRuby uses native threads, so eventually different tests may run on different cores. Sample usage. require 'test/unit/concurrent/concurrenttestunit' class MyTestCase < Test::Unit::ConcurrentTestCase def test_one end def test_two end end Test::Unit::Concurrent::ConcurrentTestRunner.run(MyTestCase)