ZenTest provides 4 different tools: zentest, unit_diff, autotest, and multiruby. zentest scans your target and unit-test code and writes your missing code based on simple naming rules, enabling XP at a much quicker pace. zentest only works with Ruby and Minitest or Test::Unit. There is enough evidence to show that this is still proving useful to users, so it stays. unit_diff is a command-line filter to diff expected results from actual results and allow you to quickly see exactly what is wrong. Do note that minitest 2.2+ provides an enhanced assert_equal obviating the need for unit_diff autotest is a continous testing facility meant to be used during development. As soon as you save a file, autotest will run the corresponding dependent tests. multiruby runs anything you want on multiple versions of ruby. Great for compatibility checking! Use multiruby_setup to manage your installed versions. *NOTE:* The next major release of zentest will not include autotest (use minitest-autotest instead) and multiruby will use rbenv / ruby-build for version management.

Hoe is a rake/rubygems helper for project Rakefiles. It helps you manage, maintain, and release your project and includes a dynamic plug-in system allowing for easy extensibility. Hoe ships with plug-ins for all your usual project tasks including rdoc generation, testing, packaging, deployment, and announcement. See class rdoc for help. Hint: `ri Hoe` or any of the plugins listed below. For extra goodness, see: http://docs.seattlerb.org/hoe/Hoe.pdf

A general classifier module to allow Bayesian and other types of classifications.

A Ruby library for text classification featuring Naive Bayes, LSI (Latent Semantic Indexing), Logistic Regression, and k-Nearest Neighbors classifiers. Includes TF-IDF vectorization, streaming/incremental training, pluggable persistence backends, thread safety, and a native C extension for fast LSI operations.

Authy plugin to add two factor authentication to Devise. This gem is deprecated, please see the README for details.

OCRA (One-Click Ruby Application) builds Windows executables from Ruby source code. The executable is a self-extracting, self-running executable that contains the Ruby interpreter, your source code and any additionally needed ruby libraries or DLL.

Serve is a small Rack-based web server that makes it easy to serve ERB or HAML from any directory. Serve is an ideal tool for building HTML prototypes of Rails applications. Serve can also handle SASS, Textile, and Markdown if the appropriate gems are installed.

Inline allows you to write foreign code within your ruby code. It automatically determines if the code in question has changed and builds it only when necessary. The extensions are then automatically loaded into the class/module that defines it. You can even write extra builders that will allow you to write inlined code in any language. Use Inline::C as a template and look at Module#inline for the required API.

Bit fields for ActiveRecord: This gem lets you use a single integer column in an ActiveRecord model to store a collection of boolean attributes (flags). Each flag can be used almost in the same way you would use any boolean attribute on an ActiveRecord object.

NMatrix is a linear algebra library for Ruby, written mostly in C and C++.

Active Record (>=3.0) plugin which allows you to hide and restore records without actually deleting them. Check its GitHub page for more in-depth information.

RubyTree is a Ruby implementation of the generic tree data structure. It provides simple APIs to store named nodes, and to access, modify, and traverse the tree. The data model is node-centric, where nodes in the tree are the primary structural elements. It supports all common tree-traversal methods (pre-order, post-order, and breadth first). RubyTree mixes in the Enumerable and Comparable modules and behaves like a standard Ruby collection (iteration, comparison, etc.). RubyTree also includes a binary tree implementation, which provides in-order node traversal besides the other methods. RubyTree can import from and export to JSON, and supports Ruby’s object marshaling.

SchemaPlus is a gem that simply pulls in a collection of other gems from the SchemaPlus family of ActiveRecord extensions

Ball Aerospace COSMOS provides all the functionality needed to send commands to and receive data from one or more embedded systems referred to as "targets". Out of the box functionality includes: Telemetry Display, Telemetry Graphing, Operational and Test Scripting, Command Sending, Logging, and more.

Ever needed to assign roles to a model, say a User, and build conditional behaviour on top of that? Enter RoleModel -- roles have never been easier! Just declare your roles and you are done. Assigned roles will be stored as a bitmask.

Ruby WebHDFS/HttpFs client

Send notifications via hipchat, slack, IRC, and email

Client library for accessing the EasyPost shipping API via Ruby.

Allows you to focus on a few tests with ease without having to use command-line arguments. Good for tools like guard that don't have enough brains to understand test output. Cf. minitest-autotest (an example of a test runner with strong testing logic). Inspired by https://github.com/seattlerb/minitest/issues/213

Adds Minitest as the default testing library in Rails