Black Box Testing Test data derived solely from specification (i.e without knowledge of internal structure of program) Need to test every possible input X:=y·2 C(since black box, only way to be sure to detect this is to try every input condition) Valid inputs up to max size of machine(not astronomical) Also all invalid input (e.g, testing Ada compiler requires all valid and invalid programs If program has"memory,, need to test all possible unique valid and invalid sequences So for most programs, exhaustive in put testing is impractical Computers and Risk White Box Testing Derive test data by examining programs logic Exhaustic path testing Two flaws 1) Number of unique paths through program is astronomical oop≤20 5+5+5+∴+5=10 100 trillion If could develop/execute/verify one test case every five minutes= 1 billion years Q夕 If had magic test processor that could develop/executelevaluate one test per msec 3170 years (control-flow graph)c ￾✂✁✂✄☎✁✂✆☎✝✂✞✠✟✌☞✱✘ ✙✝✂✖✠✚✂✛✂✜✁✂✒✆✣✢✂✞✂✤✠✥✧✦✆☎★ Black Box Testing Test data derived solely from specification (i.e., without knowledge of internal structure of program). Need to test every possible input x := y * 2 (since black box, only way to be sure to detect this is to try every input condition) Valid inputs up to max size of machine (not astronomical) Also all invalid input (e.g., testing Ada compiler requires all valid and invalid programs) If program has ‘‘memory’’, need to test all possible unique valid and invalid sequences. So for most programs, exhaustive in put testing is impractical. c ￾✂✁✂✄☎✁✂✆☎✝✂✞✠✟✌☞✱✗ ✙✝✂✖✠✚✂✛✂✜✁✂✒✆✣✢✂✞✂✤✠✥✧✦✆☎★ White Box Testing Derive test data by examining program’s logic. Exhaustic path testing: Two flaws 1) Number of unique paths through program is astronomical. loop 20x 20 19 18 14 5 + 5 + 5 + ... + 5 = 10 = 100 trillion If could develop/execute/verify one test case every five minutes = 1 billion years If had magic test processor that could develop/execute/evaluate one test per msec = 3170 years. (control−flow graph)