Chance.js is a minimalist generator of random [1] strings, numbers, etc. to help reduce some monotony particularly while writing automated tests or anywhere else you need anything random.

factory_girl is a fixtures replacement with a straightforward definition syntax, support for multiple build strategies (saved instances, unsaved instances, attribute hashes, and stubbed objects), and support for multiple factories for the same class (user, admin_user, and so on), including factory inheritance.

Mongoid (pronounced mann-goyd) is an Object-Document-Mapper (ODM) for MongoDB written in Ruby. The philosophy of Mongoid is to provide a familiar API to Ruby developers who have been using Active Record or Data Mapper, while leveraging the power of MongoDB's schemaless and performant document-based design, dynamic queries, and atomic modifier operations.

Vorlon.js is an open source, extensible, platform-agnostic tool for remotely debugging and testing your JavaScript. Powered by node.js and socket.io.

Intern is a complete test system for JavaScript designed to help you write and run consistent, high-quality test cases for your JavaScript libraries and applications. It can be used to test any JavaScript code. It can even be used to test non-JavaScript Web and mobile apps, and to run tests written for other test systems.

Etherpad is a highly customizable Open Source online editor providing collaborative editing in really real-time.

CUTE is an easy to use C++ unit testing framework that leverages modern C++ libraries and features. CUTE is orthogonal, easily extendable and much simpler than other C++ unit testing approaches like CPPUnit. For example, CUTE does not require that you write a derived class for each C++ class you want to unit test.

TestArmada is a fleet of tools for making cross-browser end-to-end testing fast, user-friendly, and valuable at scale, across large teams, without those annoying false positives.

Epydoc is a tool for generating API documentation for Python modules, based on their docstrings. A lightweight markup language called epytext can be used to format docstrings, and to add information about specific fields, such as parameters and instance variables. Epydoc also understands docstrings written in reStructuredText, Javadoc, and plaintext.

NoseGAE is a nose plugin that makes it easier to write functional and unit tests for Google App Engine applications. The plugin sets up the GAE development environment before your test run. This means that you can easily write functional tests for your application without having to actually start the dev server and test over http. Note however that this kind of testing requires that your application be a wsgi application.