Run a single test in Test::Unit

To run a single test file:

rake test:units TEST=test/unit/post_test.rb
rake test:functionals TEST=test/functional/posts_controller_test.rb
rake test:integration TEST=test/integration/admin_news_posts_test.rb

You may even run a single test method:

ruby -I test test/unit/post_test.rb -n "name of the test"
ruby -I test test/functional/posts_controller_test.rb -n test_name_of_the_test # underscored, prefixed with 'test_'

Or all tests matching a regular expression:

ruby -I test test/integration/admin_news_posts_test.rb -n "/matching string/"