Cost of Software TestingThe Graybox

Cost of Software Testing
The Graybox methodology reduces the
cost and the time of test software development
by automatically creating all test unique
software. It has been estimated that one line of
test unique code is developed for every ten
lines of application code (a 10% reduction in
SW test time). "The testing of each module
requires a special driver module and one or
more stub modules. Module driver tools are an
answer to a need discussed earlier, one must
write a small program to feed test-case input to
the module. Some driver tools also verify the
results of each test by allowing the user to
specify the expected results" [Myers79].
Previous studies have shown that what used to
take two days now takes less than four hours to
thoroughly test a unit of software (a 75%
reduction in test time). Since the cost of
maintaining and upgrading this test-use only
code is high, it is simply discarded after testing
thereby receiving the name "throw-away" code
[Panzl81]. "If a development hour costs $75,
and the average time to repair a defect in the
unit testing time is eight hours, the cost of a
defect is $600. If you remove the defect in the
system-testing phase, the cost escalates to
$825. Time and dollars are reduced by 27% for
each defect found during unit testing instead of
later in system testing" [Bianco99].