A good threat is worth a thousand tests.
A design remedy that prevents bugs is always preferable to a test method that discovers them.
A test that reveals a bug has succeeded, not failed.
If you can't test it, don't build it. If you don't test it, rip it out.
Testing proves a programmer’s failure. Debugging is the programmer’s vindication.
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.