there are some cons and pros for test  driven developement:
cons:

1 - taks twice time to write the code for a module before giving it to customer
2 - most of the changes in iran refrers to UI.how do you want to test UI automaticaly?

pros:

1- your support time would cut to one third or less.no hidden side effects when you change some part of the code.
2- time estimation for final product, would be much acceptable at the end ,and it is very important for managers.