When should I opt for test driven development?

Question

My question is same as the title. I have not done Test driven development yet,I have performed unit testing and I am aware of testing in general but I hear it is much advantageous to follow TDD?. So should I opt for it everytime or are there some preconditions... i just need to know some basic or important requirements when i should opt for TDD. Sorry if this question is too trivial.

Answer 1

IMHO if you are not comfortable with TDD, trying to apply it in projects where you will need to interact/use legacy code it's much more complex than applying it in a project from scratch. In fact, there is a whole book about this.

HTH

Answer 2

I would say whenever you are coding for a project. By this I mean where you are hoping to produce code that will be used by people. This is basically all code apart from research where you are learning and discovering new techniques.

Even if you think the project is just a small one often things spiral up out of control without care. You wil be glad for the tests when you find yourself having to refactor a big sprawl of code.

Also note that tdd isn't just about testing. It is a methodology of development that encourages you to create clean and solid designs.

As you are starting out tdd everything. Once you have more experience then perhaps you can back off and determine when to not tdd.

Answer 3

My advice would be to use unit testing as often as possible.

Caveat: In my experience TDD works best when working with technologies you already have some experience with. It's often hard to write test assertions if you do not know exactly what the desired result looks like (For example, try writing the test for an ASP.NET MVC action method if you never wrote an action method in your entire life). In those cases you're probably better off writing unit tests after implementing the code.

Answer 4

If I am developing something without a user interface, I always use TDD these days. After all, you have to test the software. You can either do the extra work and do TDD, or you can do the extra work and cludge together a user client just for testing. The former tests more completely and in a more repeatable fashion.

Doing TDD against user interface code, on the other hand, hasn't really delivered much value for me. For various business reasons I'm restricted to Visual Studio out of the box for my work, and "recording" tests with VS is a huge time sink, especially when you have to re-record them if you change the UI. I do TDD for the business logic behind the UI, but not the UI itself.