Making Changes To Standard Libraries

Everything in the lib directory is mirrored from a standalone repository into the Ruby repository. If you’d like to make contributions to standard libraries, do so in the standalone repositories, and the changes will be automatically mirrored into the Ruby repository.

For example, CSV lives in a separate repository and is mirrored into Ruby.


You can find the list of maintainers here.


First, install its dependencies using:

bundle install

Libraries with C-extension

If the library has a /ext directory, it has C files that you need to compile with:

bundle exec rake compile

Running tests

All standard libraries use test-unit as the test framework.

To run all tests:

bundle exec rake test

To run a single test file:

bundle exec rake test TEST="test/test_foo.rb"

To run a single test case:

bundle exec rake test TEST="test/test_foo.rb" TESTOPS="--name=/test_mytest/"