Any way to automate - for testing - a human-dependant action?

Question

I wonder if there are any good / possible ways to automate - for a unit test perhaps - a human-dependant action on an eCommerce website?

For example, could I have a macro or a script to simulate "can user put items in basket?" or "can user reach the payment gateway?".

I am currently managing a very heavily used eCommerce codebase and would like to be able to quickly verify that any changes I implement are not going to goof things up for the end user.

Comment is free ;-)

[codebase is PHP by the way]

Answer 1

Check out Selenium... All the tests execute in a browser, so you can test your JS, etc...

Edit:

Oh, and the REALLY cool thing, is if you use Selenium Grid, you can then scale out your already written tests to multiple browsers and platforms. So you write your test once, and then can run it (simultaneously) on literally dozens of different browser/platform combinations. You'll still need to intelligently write your test cases, but once you do you can use it to detect problems on other browsers (Test for JS errors/crashes)...