Software testing combination at Google

From IT Inform

However, simply looking at the collective whole does not find a lot of problems. At least it doesn’t find a lot of important problems.

Test driving a car is looking at a car holistically. But how often does a test drive find a real bug? A test drive is about look and feel; it’s too high level to be a good bug finding exercise. To find a bug, you hire a mechanic to look at the car, component by component and subsystem by subsystem. Mechanics don’t test by driving the car on a date or by taking a Sunday drive. They test by monitoring specific subsystems and by looking for specific types of problems that eventually work their way out as a bug on a Sunday drive. A mechanic finds flaws quickly in the fuel system, the exhaust system, the electrical system. Sunday drivers must be patient for such flaws to work their way into their line of sight.

Proper software testing requires a combination of Sunday driving and a mechanic’s analysis. It is about looking at the big picture and analysing individual components and capabilities and how they contribute to the collective whole. The way we now do exploratory testing at Google treats it as such.