Running test on Production Code/Server

Question

I'm relatively inexperienced when it comes to Unit Testing/Automated Testing, so pardon the question if it doesn't make any sense.

The current code base I'm working on is so tightly coupled that I'll need to refactor most of the code before ever being able to run unit tests on it, so I read some posts and discovered Selenium, which I think is a really cool program.

My client would like specific automated tests to run every ten minutes on our production server to ensure that our site is operational, and that certain features/aspects are running normally.

I've never really thought to run tests against a production server because you're adding additional stress to the site. I always thought you would run all tests against a staging server, and if those work, you can just assume the prouction site is operational as long as the hosting provider doesn't experience an issue.

Any thoughts on your end on testing production code on the actual production server?

Thanks a lot guys!

Answer 1

Maybe it would help if you thought of the selenium scripts as "monitoring" instead of "testing"? I would hope that every major web site out there has some kind of monitoring going on, even if it's just a periodic PING, or loading the homepage every so often. While it is possible to take this way too far, don't be afraid of the concept in general. So what might some of the benefits of this monitoring/testing to you and your client?

1. Somehow not all the best testing in the world can predict the odd things users will do, either intentionally or by sheer force of numbers (if 1 million monkeys on typewriters can write Hamlet, imagine what a few hundred click happy users can do? Pinging a site can tell you if it's up, but not if a table is corrupted and a report is now failing, all because a user typed in a value with a umlaut in it.

2. While your site might perform great on the staging servers, maybe it will start to degrade over time. If you are monitoring the performance of those selenium tests, you can stay ahead of slowness complaints. Of course as you mentioned, be sure your monitoring isn't causing problems either! You may have to convince your client that certain test are appropriate to run every X minutes, and others should only be run once a day, at 3am.

3. If you end up making an emergency change to the live site, you'll be more confident knowing that tests are running to make sure everything is ok.