There are many types of testing, almost all of which are useful. From a client perspective, usability testing is probably the most important. Having a testing

There are many types of testing, almost all of which are useful. From a client perspective, usability testing is probably the most important. Having a testing group come in, use your app, and then give you immediate feedback is invaluable. There is also penetration testing to check you web apps security. Could you maybe be more specific? I think it would help you get some great answers from the community.