Why should I practice Test Driven Development and how should I start?

Question

Lots of people talk about writing tests for their code before they start writing their code. This practice is generally known as Test Driven Development or TDD for short. What benefits do I gain from writing software this way? How do I get started with this practice?

Answer 1

There are a lot of benefits:

• You get immediate feedback on if your code is working, so you can find bugs faster
• By seeing the test go from red to green, you know that you have both a working regression test, and working code
• You gain confidence to refactor existing code, which means you can clean up code without worrying what it might break
• At the end you have a suite of regression tests that can be run during automated builds to give you greater confidence that your codebase is solid

The best way to start is to just start. There is a great book by Kent Beck all about Test Driven Development. Just start with new code, don't worry about old code... whenever you feel you need to refactor some code, write a test for the existing functionality, then refactor it and make sure the tests stay green. Also, read this great article.