We just finished day 1 of TDD master class in Norway. Here’s what people had to say about TDD and Pair Programming which they did half of the day:

When doing TDD it is:

• Easier to isolate a problem
• Probably less bugs
• Better API design
• More thinking about what you are writing
• More tests
• Cleaner tests
• Less debugger
• More confidence in the code
• Api documentation (up to date)
• Able to ”move on” to other tasks once finished
• More focus
• Code coverage (everyone has 94-100%)
• Quick feedback when you fail or break
• Didn't write extra unneeded code
• Think about requirements of API
• Easy refactoring

When working in pairs:

• better Interacting (sparing)
• You learn something from the other person
• Good for teaching and mentoring
• Instant code review
• Very productive and focused
• No time wasted
• Mostly fun
• Shared code ownership (bus factor)