4)DOES “TESTING ALONE DOES NOT ENSURE GURANTEED SOFTWARE”?
EVERY METHOD we use is to prevent and find bugs leaves a residue of subtler bugs against which those methods are ineffectual.
TESTING alone will not gurantee to make software better complexity barrier states.software complexity grows to limit of our ability to manage that complexity
By eliminating easy bugs you allowed another escalation of features &complexity,but this time you have subtler bugs to face ,just to retain reliability you had before.
If a failure occour during prelimnary testing &code is changed software may now work for testCase that is didn’t work previously.But its behaviour on pre-error test case is passedbefore can no longer be guaranteed.
Software bugs will almost exists in any software module with moderate size,not because programmes are careless or irresponsible but because complexity of software is generally intraceble and human have only limited ability to manage complexity.
SO by this we can conclude that SOFTWARE TESTING is process of executing a program or system
Intent of finding error.software is unlike other physical where input are received and output are
Produced.SO detecting all different failure mode for software is generally infeasible.