an Automated Pythonic Code Tester. This package is designed to run tests on a code repository on a daily basis. It comes with a set of predefined test, essentially for python packages, and a set of predefined reports to display execution results. However, it has been designed to be highly extensible, so you could write your own test or report using the Python language.

Aqua is a new Ruby library that aims to painlessly persists objects, allowing developers to focus more on object oriented code and less on storage.

An open-source database with a flexible data model for documents, graphs, and key-values. Build high performance applications using a convenient sql-like query language or JavaScript/Ruby extensions.

Arbiter is a requirements gathering and acceptance testing tool for project managers and web developers, to help ease client interaction. The project specification can be defined in word processor format as you would normally. By adding some special items, such as titled bulleted lists and highlighted text items, both a test suite and glossary can be written right into the spec. The Arbiter server will parse these documents and run the tests, reporting the results into the documents themselves. This allows the client to see project process.

It also allows the developers, sitting next to the client, to add concrete executable examples of the use cases. This adds clarity and helps to settle disputes over required functionality. Using the glossary, developers can signal to the client that concepts are not well understood. Tests can be marked pending if a document contains unexplained glossary items.

Archetype is designed to fill the gap that other frameworks and libraries leaves in the (script removed) Structure and ease of development.

Archi is a free, open source, cross-platform tool to create ArchiMate models. ArchiMate1 is an open and independent Enterprise Architecture modelling language that supports the description, analysis and visualization of architecture within and across business domains.

ArchStudio is an open-source software and systems architecture development environment developed by the Institute for Software Research at the University of California, Irvine. It is an environment of integrated tools for modeling, visualizing, analyzing and implementing software and systems architectures. It is based on the Eclipse open development platform. It is released under a BSD-style license.

Arepa is a lightweight non-invasive tool that helps you to implement Behavior Driven Development (BDD) on .NET projects. Arepa produces guidelines of using BDD on your current tests, and customisable and portable test reports integrating XML Documentation Comments. It's developed in C# using Scrum and BDD.

ArgoUML is an open source UML modeling tool and includes support for all standard UML 1.4 diagrams. It runs on any Java platform and is available in ten languages. ArgoUML provides the following features: All 9 UML 1.4 Diagrams supported, Platform Independent: Java 1.4+, Standard UML 1.4 Metamodel, XMI Support, Export Diagrams as GIF, PNG, PS, EPS, PGML and SVG,, Advanced diagram editing and Zoom, Forward Engineering, Reverse Engineering / Jar/class file Import, Cognitive Support, Reflection-in-action, Design Critics, Opportunistic Design, Comprehension and Problem Solving

AribaWeb is the Open Source component-based web application development framework for creating rich, AJAX-enabled applications with the absolute minimum of code (and no hand-coded Javascript).