Maintainable and Testable Code in the Age of AI

For more than 30 years, I've been searching for the right balance between maintainable code and effective test coverage. During the last 15 years, I've practiced Test-Driven Development extensively and learned first-hand that even well-established practices can be applied poorly. The same is true for coding standards, object-oriented design, SOLID principles, and many of the other ideas that have shaped our profession. Today, AI tools such as JetBrains Junie, Anthropic Claude, and GitHub Copilot have become part of my daily workflow. In this interactive two-hour workshop, we'll explore the principles behind maintainable, testable code and examine how AI can help—or hinder—our efforts. Drawing on lessons from both client projects and open-source work, including a project with more than 700 million downloads, I'll share practical techniques that have stood the test of time and discuss how they fit into modern AI-assisted development. The workshop is designed to be highly interactive. Alongside short presentations, participants will analyze code, discuss design decisions, refactor existing code, and write tests. Most examples will be based on Fluent Assertions, but the concepts apply broadly, and we'll adapt the exercises to the experience level of the audience.