My First Day Agile Programming

Today was the first day i started doing Test First Development. I had been thinking that i was doing TDD for the past couple of months. After my TDD training during the last 3 days, i realised that all i had been doing was just glorified unit testing and not TDD.

I used to have a pre-conceived class diagram and the methods which should be present in a class and then go about writing Junit and Java classes in parallel. What i learnt and was a bit surprised to learn was TDD was nothing but it..

I started working on a web application today and wanted to give what i learnt a shot. The application was a typical web-app. There was a screen which had a list of search results. On clicking on a row, it was supposed to bring the details of the entry..

Typically i would have started off with a basic class diagram and a sequence diagram (if time permits) and then would have set out coding... Today i did the opposite...

- I first came up with the list of test cases.. I was surprised to come up with 24 high level test cases for what seemed a not so complex problem

- Then picked up the smallest test case.. This is what Brian Button taught me in my class. Start off with a small test case and then build towards the complex ones..

- I wrote a test which did not even compile.

- Then did just enough to make sure the test compiles.. Then ran the test and saw it failing. But that's what you expect..

- Then wrote a hard-coded implementation to make the test pass..

- Kept doing up to three tests until i saw a pattern emerging.. The way interfaces emerge out of nowhere and a beautiful inheritance tree emerge was so pleasing to see.

- By end of the day i had a working system of high quality.. Not all tests were implemented, but the ones that were implemented was beautiful to see..

Compared to my last 7 years of Java experience, it would have at least taken 3 - 4 days before i started coding and within 3 to 4 hours of coding, i would have changed my design at least a little bit... It really does make sense developing this way.

I gave the estimate for this work before the agile class. It was assuming an RUP way of development. It will be interesting to see how much effort i actually take with this approach.

I should also try to learn how i do TDD f0r the code that lives close to the persistence layer. I am not sure how to get that done.. If anyone has any ideas do post it in here...

Thanks for reading, am sure i will be posting more of my experiences...