Antelink launched in April a free byproduct from their R&D that enables the Open Source Community to check how many times a library is reused in Open Source projects. As previously discussed here, this service already demonstrate that 3% of all the open source software ever created uses the Apache Commons libraries.
In order to get the spotlight on open source projects, Antelink proposes a weekly blog article on the most reused Open Source Project.
The first project is JUnit, the famous Java automated test framework. It's interesting to see that many projects seems to be stuck on the last version of the 3.X branch, using the previous implementation based on class inheritance from the framework interfaces. JUnit 4.x introduced a new way to implement tests, based on the Java 5 annotations.
We also compared (in terme of reuse by open source project) JUnit to TestNG, which may be the most promising alternative implementation.