Software Testing

Software Testing

1. Testing, what is it?

   • Executing a program in the intent of finding errors

2. Objectives

   • Finding defects
   • Preventing defects
   • Gain Confidence
     • To gain confidence about the level of quality of the product or program.

3. Why It Should Occur

   • Requirements Phase
     • Review Requirements
     • Determine the Adequacy of Requirements
   • Design Phase
     • Determine consistency with requirements
     • Determine adequacy of design
     • Generate test conditions
   • Build Phase
     • Determine consistency with design
     • Determine adequacy of implementation
   • Test Phase
     • Execute test cases
     • Determine the adequacy of test plan
   • Maintenance Phase
     • Modify and Retest

4. Why Faults Occur

   • Software is written by human beings
   • Strict deadlines

5. Testing Principles

   • Testing shows presence of defects
     • Proves that defects are present but it cannot say that there are 0 defects in the system. Though we don't find any defects we cannot prove that there are no defects in the system.
   • Exhaustive testing is impossible
     • Testing all input combinations are impossible so it will be based on priority. 
   • Early testing
     • Testing should start as early as possible and it should focus on defined objectives.
   • Defect clustering
     • defects can exist in certain clusters. fixing a defect may introduce new defects in the cluster so the whole cluster should be tested for defects.
   • Pesticide Paradox
     • If same tests are repeated we won't be finding new errors. Therefore, new test cases should be designed. 
   • Context dependent
     • Each software is tested differently
   • Absence-of-errors fallacy
     • no point in finding and fixing errors if, the customer requirements are not met.

6. Test Planning & Control

   • Test Planning
     • Activity of varifying the mission of testing
     • Identify objectives
     • Specify test activities
   • Test Control
     • Monitoring progress by comparing actual against the planned
     • Takes action to meet mission objectives

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