Automation is tricky business. Knowing when to employ it (and when not to) is a decision with major consequences. Here with some good advice on test automation is James Bach, who had this to say in a 2009 interview with uTest’s Matt Johnston. Check it out:

Here’s how I think of it:

- Is the product highly controllable and observable? A command line tool that provides its output solely to the console window is inexpensive to automate, compared to an iPod touchscreen app. I want to get under the GUI.

- How expensive is the tool I’m using? I urge you not to use expensive tools, even if they work. Never let your manager buy them. Because expensive tools become something you MUST use, even if they don’t work. A free tool may be freely abandoned. This gives you flexibility.

- How well can I automate the oracle? Will the bugs be able to elude my automation because it can’t tell if a complex graphic is rendered correctly?

- What is the learning and testing value I’m giving up by using automated checks? I find that doing a test multiple times also causes me to learn and see new things in the product. Furthermore, when I re-run tests, I often run them in a different way, and that allows me to find new bugs.

- Can the automated check be parameterized and randomized, so that I get lots of similar checks for very little additional investment? I like automation more for data intensive testing, because I get new tests just by changing the database.

- Is the technology “Pyramid shaped?” In some products lot of underlying code boils up to one simple output, by placing checks on that output, we may be able to find lots of bugs. In other products, there are many different pathways, and you need a lot more checks to get decent coverage.

- How critical are the checks to the business? Is this critical functionality? Is it a common usage scenario? There are candidates for smoke testing.

- Is this part of the product especially prone to breaking? If so, that may be good for automation, UNLESS, it breaks in a way that breaks the automation.

- When I automate, I do it incrementally, in small bits.

I want automated checks for high value, highly testable parts of the product, and I want to do them in such a way as they aren’t constantly breaking or giving me false readings. I want to augment those checks periodic sapient testing as a cross-check.

Do you have some automation tips you’d like to share? The comments section is all yours.