Capybara is an integration testing tool for rack based web applications. It simulates how a user would interact with a website.

Sawyer is an experimental hypermedia agent for Ruby built on top of Faraday.

This library can be used as a module for fog or as standalone libvirt provider. fog is a Ruby cloud services library.

ruby_engine provides an RubyEngine class that can be used to check which implementation of Ruby is in use. It can provide the interpreter name and provides query methods such as RubyEngine.mri?.

KPeg is a simple PEG library for Ruby. It provides an API as well as native grammar to build the grammar. KPeg supports direct left recursion of rules via the OMeta memoization technique.

This library only provides the FFI wrapper for the ZeroMQ networking library. It can be used to implement a Ruby API for the ZeroMQ library.

Mail is an internet library for Ruby that is designed to handle email generation, parsing and sending. The purpose of this library is to provide a single point of access to handle all email functions, including sending and receiving emails. All network type actions are done through proxy methods to Net::SMTP, Net::POP3 etc.

Mail has been designed with a very simple object oriented system that really opens up the email messages you are parsing, if you know what you are doing, you can fiddle with every last bit of your email directly.

Coderay is a Ruby library that provides syntax highlighting for select languages.

Hashie is a collection of classes and mixins that make Ruby hashes more powerful.

The FileUtils Ruby library includes Several file utility methods for copying, moving, removing, etc.

BlankSlate provides an abstract base class with no predefined methods (except for __send__ and __id__). BlankSlate is useful as a base class when writing classes that depend upon method_missing (e.g. dynamic proxies).

This package provides a MiniTest plugin for displaying the slowest tests in a minitest suite.

This package provides a drop-in replacement for the prettyprint gem, with more functionality.

Asciidoctor is a text processor and publishing toolchain for converting AsciiDoc content to HTML5, DocBook 5, PDF, and other formats.

Launchy is helper class for launching applications in a fire and forget manner. The aim of Launchy is to provide a common approach to launching external applications from within Ruby programs.

This package provides a simple block-driven assertion library for both testing and for production code that attempts to make test definitions more readable.

Assertive Expressive (AE) is an assertions library specifically designed for reuse by other test frameworks.

Systemu can be used on any platform to return status, stdout, and stderr of any command. Unlike other methods like open3 and popen4 there is no danger of full pipes or threading issues hanging your process or subprocess.

Rerun is a tool to launch programs, then monitor the file system, and restart the program when any of the monitored files change. It's written in Ruby, but can be used for all programs.

Swagger::Diff is a utility for comparing two different Open API Initiative (OAI) specifications (formerly known as Swagger specifications). It is intended to determine whether a newer API specification is backwards-compatible with an older API specification.

Psych is a YAML parser and emitter. Psych leverages libyaml for its YAML parsing and emitting capabilities. In addition to wrapping libyaml, Psych also knows how to serialize and de-serialize most Ruby objects to and from the YAML format.

This package provides a Ruby port of EventEmitter from Node.js.

Formatador is a Ruby library to format text printed to the standard output stream.

This library contains some useful functionality to support the development of Ruby gems.