Test Readability

When over half your codebase is composed of unit-tests its important to apply good coding practices to your unit-tests as much to non-test code.

Making Test Driven Development Work: Test Readability | Javalobby

A key characteristic of TDD that works is test readability. By focusing on test readability, a developer is forced to think about the object under test in a way that will promote good design and provide valuable documentation for the components of the system.