If you don’t have the environment set make sure to read
http://edgeguides.rubyonrails.org/contributing_to_ruby_on_rails.html#testing-active-record
You can run a particular test file from the command line, e.g.
$ ruby -Itest test/cases/base_test.rb
To run a specific test:
$ ruby -Itest test/cases/base_test.rb -n test_something_works
You can run with a database other than the default you set in test/config.yml, using the ARCONN environment variable:
$ ARCONN=postgresql ruby -Itest test/cases/base_test.rb
You can run all the tests for a given database via rake:
$ rake test_mysql
The ‘rake test’ task will run all the tests for mysql, mysql2, sqlite3 and postgresql.
By default, the config file is expected to be at the path test/config.yml. You can specify a custom location with the ARCONFIG environment variable.