The Art Of Unit Testing, Second Edition Direct

A significant portion is dedicated to the "untestable." It offers strategies for breaking dependencies in tightly coupled code, allowing you to wrap older systems in tests without a total rewrite.

Osherove emphasizes that a test suite is useless if developers don’t trust it. He provides concrete techniques to eliminate "flickering" or flaky tests and ensures your suite acts as a reliable safety net rather than a maintenance burden. The Art of Unit Testing, Second Edition

While examples primarily use C# , the principles are designed to be universally applicable to Java, JavaScript, Python, and other object-oriented languages. A significant portion is dedicated to the "untestable