I’ve just started my Private Pilot’s License project, and the first order of business was to get a Class 2 medical. Being a triathlete and considering myself fairly healthy, I expected that to be a formality. To my surprise, the examiner detected that my blood pressure was too high, and I’ll have to work on getting it down before I can fly solo.
Similarly, I’m sure that Delta Airlines considered their data center fairly healthy. Unfortunately, they did not test. So when the power supply disappeared, they discovered that 300 out of 7,000 devices were not properly connected to backup power. And 2,000 planes were grounded.
If you don’t test, you don’t know.