“Software never was perfect and won’t get perfect. But is that a license to create garbage? The missing ingredient is our reluctance to quantify quality.”

More than the act of testing, the act of designing tests is one of the best bug preventers known.

First law: The pesticide paradox. Every method you use to prevent or find bugs leaves a residue of subtler bugs against which those methods are ineffective.

Bugs lurk in corners and congregate at boundaries.

If you can’t test it, don’t build it. If you don’t test it, rip it out.