Drupal_TDD is a resource that offers code and sample applications designed to facilitate Test Driven Development (TDD) and unit testing within the Drupal framework. It includes a GitHub repository managed by Pat Shaughnessy, which provides tools and examples for developers looking to implement TDD practices in their Drupal projects. Regular updates and additional information are available through Mark Bennett's blog, ensuring that users have access to the latest advancements and discussions in the field. The initiative is part of a broader effort to enhance testing methodologies in Drupal, as highlighted by contributors such as Chris Wanstrath.