Software Testing - Concepts and Principles

Purposes of Software Testing are

• Analyzing a program to prevent failures

• To check whether the users need are satisfied

• To show good knowledge

• To check if the system does what it is expected to do

Defect Masking

• a fault is shown by one or more other faults in other parts of the program

• a fault is hidden by one or more other faults in other parts of the program

• a fault is hidden by one or more developers

• a fault is hidden by one or more other codes in other parts of the program

Software Failure

• Present from the time the software was developed but only when the software is executed, becoming visible as a failure

• An incorrect internal state that is the manifestation (symptom/sign) of some fault.

• Discrepancy between the actual result/behavior and the expected result/behavior

• Also known as bug, defect or internal error.

Software Fault

• Present from the time the software was developed but only when the software is executed, becoming visible as a failure

• An incorrect internal state that is the manifestation (symptom/sign) of some fault.

• Discrepancy between the actual result/behavior and the expected result/behavior

• Also known as bug, defect or internal error.

Software Error

• Present from the time the software was developed but only when the software is executed, becoming visible as a failure

• An incorrect internal state that is the manifestation (symptom/sign) of some fault.

• Discrepancy between the actual result/behavior and the expected result/behavior

• Also known as bug, defect or internal error.

"Finding failures and repairing defects does not guarantee that the system meets user expectations and needs" relate to principle -

• Exhaustive testing is impossible

• Testing shows the presence of defects, not their absence

• No failures means the system is useful,

  is a fallacy

• The pesticide paradox

"It’s impossible to run an exhaustive test that includes all possible values for all inputs and their combinations combined with all different preconditions." relate to principle -

• Exhaustive testing is impossible

• Testing shows the presence of defects, not their absence

• No failures means the system is useful,

  is a fallacy

• The pesticide paradox

"Testing can show that the product fails, i.e., that there are defects" relate to principle -

• Exhaustive testing is impossible

• Testing shows the presence of defects, not their absence

• No failures means the system is useful,

  is a fallacy

• The pesticide paradox

"if the same tests are repeated over and over, they tend to lose their effectiveness - not able to disclose new defects" relate to principle -

• Exhaustive testing is impossible

• Testing shows the presence of defects, not their absence

• No failures means the system is useful,

  is a fallacy

• The pesticide paradox

Debugging and Testing,

• Debugging is not testing

• Both are same

• Debugging supports testing

• Debugging is the process of analyzing and locating bugs