Pre-loading VMs to optimize automated testing

A really cool feature we recently added to HostedQA was the ability to pre-load virtual machines in order to optimize automated testing. At first, I wasn’t sure if this was going to have any real user experience impact. But after having built it, I wish I’d done it sooner.

It turns out, if you have the RAM and you’re using VMs for automated testing, you should really think about pre-loading your VMs ahead of time. Then instead of waiting several minutes to kick off your automated tests, they can begin right away.

Now granted that if your test suite takes 10 hours, then a 3 minute gain isn’t that important. But that’s not the use case that this is designed to optimize. Instead, this feature, and the general concept of pre-loading VMs, is all based around the use case of creating new tests.

Why creating? Often when someone writes a complex test case that depends on the entire system being deployed and working properly, they don’t want to go too far without verifying they are on the right track. They do this by running the test. Now your 10 second test actually takes 10 seconds to run, instead of 3 minutes and 10 seconds. Suddenly, the environment is much more hospitable for test creators.