Testing Alone Is Not Enough
Watts S. Humphrey, a renowned expert on software quality, defines a software defect as anything that must be changed before delivery of the program
Testing does not sufficiently prevent software defects because:
The number of ways to test a complex system is huge
Users will continue to invent new ways to use a system that its developers never considered
Humphrey suggests that people rethink the software development process to provide no potential defects when you enter system testing; developers must be responsible for providing error-free code at each stage of testing