Core

Core test issues can be found here. There is an automated testing in Drupal page in the Developing for Drupal handbook that should help you get started with those issues.

Here are some patches that affect things like the coding standards compliance, testing framework, the tests themselves, and tools that enable QA people to nitpick:

• #301005: Add "expected fail" functionality to simpletest
• #250047: Rework the SimpleTest results interface and clean-up of backend code
• #314112: Add an easy way to write debug statements
• #343502: Allow tests to require and test existance of contrib modules
• #300993: User roles and permissions API
• #348455: Provide a scalable way to ensure a clean testing environment for SimpleTest