ActionPack provides conventions for building and testing MVC web applications. These work with any Rack-compatible server.

Solargraph provides a comprehensive suite of tools for Ruby programming: intellisense, diagnostics, inline documentation, and type checking.

This package adds step-by-step debugging and stack navigation capabilities to pry, using byebug.

This Ruby library is controlling and communicating with spawned processes. It is designed after Python's subprocess module.

Bio-logger is a wrapper around Log4r adding extra logging features such as filtering and fine grained logging.

The SnakyHash Ruby library provides classes for normalizing hash keys and look-ups, and a pseudo-object interface.

pkg-config can be used in your extconf.rb to properly detect need libraries for compiling Ruby native extensions.

rb-inotify is a simple wrapper over the inotify Linux kernel subsystem for monitoring changes to files and directories.

Prawn::Icon provides various icon fonts including FontAwesome, PaymentFont and Foundation Icons for use with the Prawn PDF toolkit.

Given a string pattern, Mustermann will turn it into an object that behaves like a regular expression and has comparable performance characteristics.

This extends the bacon testing framework with useful extensions to disable tests, have before and after blocks that run once and more.

Deep Merge is a set of utility functions for Hash. It permits you to merge elements inside a hash together recursively.

Given_core is the basic functionality behind rspec-given and minitest-given, extensions that allow the use of Given/When/Then terminology when defining specifications.

multi_test provides a uniform interface onto whatever testing libraries that have been loaded into a running Ruby process to help control rogue test/unit/autorun requires.

This package provides actionable code coverage reports for Ruby projects. It has very little overhead and can be easily integrated with development tools to catch coverage problems early.

This package provides a common interface to multiple JSON libraries, including Oj, Yajl, the JSON gem (with C-extensions), the pure-Ruby JSON gem, NSJSONSerialization, gson.rb, JrJackson, and OkJson.

Rack::Cache is suitable as a drop-in component to enable HTTP caching for Rack-based applications that produce freshness (Expires, Cache-Control) and/or validation (Last-Modified, ETag) information.

Lumberjack is a simple logging utility that can be a drop in replacement for Logger or ActiveSupport::BufferedLogger. It provides support for automatically rolling log files even with multiple processes writing the same log file.

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).

The PDF::Reader library implements a PDF parser conforming as much as possible to the PDF specification from Adobe. It provides programmatic access to the contents of a PDF file with a high degree of flexibility.

The mime-types library provides a library and registry for information about Multipurpose Internet Mail Extensions (MIME) content type definitions. It can be used to determine defined filename extensions for MIME types, or to use filename extensions to look up the likely MIME type definitions.

The httpclient ruby library provides functionality related to HTTP. Compared to the net/http library, httpclient also provides Cookie, multithreading and authentication (digest, NTLM) support.

Also provided is a httpclient command, which can perform HTTP requests either using arguments or with an interactive prompt.

The test-queue module is a parallel test runner, built using a centralized queue to ensure optimal distribution of tests between workers. It is specifically optimized for Continuous Integration (CI) environments: build statistics from each run are stored locally and used to sort the queue at the beginning of the next run.

With Serverspec, you can write RSpec tests for checking your servers are configured correctly.

Serverspec tests your servers’ actual state by executing command locally, via SSH, via WinRM, via Docker API and so on. So you don’t need to install any agent software on your servers and can use any configuration management tools, Puppet, Ansible, CFEngine, Itamae and so on.

But the true aim of Serverspec is to help refactoring infrastructure code.