.NET Rocks!

You write tests - but are they valuable tests? Carl and Richard talk to Egil Hansen about his approach to creating tests for applications. Egil discusses the types of testing and who they impact. Testing isn't only for you! Valuable tests are also durable, being able to persist between changes where it makes sense, and help to understand when updates are going to create problems. The role of LLMs in generating code comes into play: should AI write your tests, evaluate them, or do both? Lots of great thinking from someone who's been helping developers build better tests for years!

AI in the cloud dominates, but what can you run locally? Carl and Richard speak with Joe Finney about his work in setting up local machine learning models. Joe discusses the non-LLM aspects of machine learning, including the vast array of models available at sites like Hugging Face. These models can help with image recognition, OCR, classifiers, and much more. Local LLMs are also a possibility, but the hardware requirements become more significant - a balance must be found between cost, security, and productivity!

James Montemagno, a Microsoft developer advocate focused on cross-platform .NET and AI tools, shares his insights on the evolution of coding with AI in Visual Studio Code. He contrasts various LLMs like GPT and Claude, explaining their strengths in coding tasks. The discussion dives into 'vibe coding', where AI is harnessed to streamline development while ensuring quality control. Montemagno emphasizes the importance of verifying AI outputs and the shift in developer roles toward greater architectural responsibility. A must-listen for those curious about AI's impact on development!

David Wengier, a principal software engineer at Microsoft, leads the Razor tooling experience for Visual Studio and VS Code. In this chat, he reveals the exciting co-hosting model with Roslyn that turbocharges Razor performance and reliability. David dives into the shared capabilities between Visual Studio and VS Code, enhancing developer tools through the Language Service Protocol. He also shares upcoming improvements in Visual Studio 2026, including faster Hot Reload and bug-fixing guidance, making for a more seamless coding experience.

In this engaging chat, Mads Kristensen, a Program Manager for the Visual Studio team at Microsoft and extension enthusiast, shares exciting developments for the upcoming Visual Studio 2026. He discusses deep AI integration for tasks like code completion and debugging, making the developer experience smoother than ever. The conversation also touches on Visual Studio's role in project management and its seamless integration with cloud services and GitHub, while recalling humorous moments from the past and the evolution of development tools.

In this engaging discussion, Michael Levan, a seasoned engineer and Microsoft MVP, shares insights on the transformation of DevOps in 2025. He highlights how AI tools are streamlining workflows from coding to deployment. Michael also tackles pressing security challenges, including misconfigurations and the importance of maintaining a software bill of materials. His emphasis on collaboration and proactive security measures sets the stage for a future where teams can effectively focus on enhancing customer value.

How did the design of GitHub evolve? Carl and Richard speak with Diana Mounter about her experiences at GitHub, including her role as head of design. Diana discusses how she was drawn to GitHub as a designer and how her career evolved to lead design for the company. The conversation ranges over different design concepts, the Primer design language, and how to effectively combine design and development to achieve great results.

What's coming in C#14? Carl and Richard chat with Dustin Campbell about the next version of C#, discussing what it takes to continue advancing software development in the Microsoft ecosystem. Dustin discusses how features are selected from version to version, including long-developed features like extension members, which have been in development for years. The conversation also turns to Razor Pages, which Dustin helps contribute to, and the dynamic of what should be language, what should be framework, and what should be tooling. And there's much more to come!

Michael Howard, Senior Director at Microsoft Red Team with over 33 years in security, dives into the evolution of application security. He explores the role of Red Teams in identifying vulnerabilities by simulating black hat attacks. The discussion spans improved security tools, the significance of integrating security into agile development, and the need for user-friendly solutions. They also touch on the challenges of memory-safe programming, historical security failures, and the critical impact of human behavior on cybersecurity.

Can you improve a legacy application? What's the right way to go about it? Carl and Richard talk with Billy Hollis about his work updating legacy applications, starting with the most essential question: should you? Billy begins by defining what it means to be a legacy application and how, invariably, these applications are critical to the organization, so you have to tread lightly. Typically, the focus is on modernizing the client-side of the app, which brings us to the crux of the matter: Are the workflows of the company today well reflected in the older application? Lots of great thoughts from one of the longest-serving guests of .NET Rocks!