Testing Principles
- 1. Risma Rustiyan R Testing Principles Information System Department Faculty of Science and Technology State Islamic University of Sulthan Syarif Kasim Riau 2017
- 2. Agenda 1. Testing shows presence of defects 2. Exhaustive testing is impossible 3. Early testing 4. Defect clustering 5. Pesticide paradox 6. Testing is context dependent 7. Absence-of-errorsfallacy
- 3. Principle 1 Testing can show that defects are present, but cannot prove that there are no defects. Testing reduces the probability of undiscovered defects remaining in the software but, even if no defects are found, it is not a proof of correctness. Testing shows presence of defects
- 4. Principle 2 Testing everything (all combinations of inputs and preconditions) is not feasible except for trivial cases. Instead of exhaustive testing, we use risks and priorities to focus testing efforts. Exhaustive testing is impossible
- 5. Principle 3 Testing activities should start as early as possible in the software or system development life cycle and should be focused on defined objectives. Early testing
- 6. Principle 4 A small number of modules contain most of the defects discovered during pre- release testing or show the most operational failures. Defect clustering
- 7. Principle 5 If the same tests are repeated over and over again, eventually the same set of test cases will no longer find any new bugs. To overcome this 'pesticide paradox', the test cases need to be regularly reviewed and revised, and new and different tests need to be written to exercise different parts of the software or system to potentially find more defects. Pesticide paradox
- 8. Principle 6 Testing is done differently in different contexts. For example, safety-critical software is tested differently from an e- commerce site. Testing is context dependent
- 9. Principle 7 Finding and fixing defects does not help if the system built is unusable and does not fulfill the users' needs and expectations. Absence-of- errorsfallacy
- 10. Reference Graham, Dorothy, et al. âFoundation of Software Testing ISTQB Certificationâ. Chapter 1 Fundamentals of Testing. 2011