1.3 Testing Principles Flashcards
Does testing show the presence or absence of defects?
Testing shows the presence, not the absence of defects.
Is exhaustive testing feasible?
Exhaustive testing is impossible except in trivial cases.
How do we decide what to test if we don’t test everything?
Test techniques, test case prioritization, and risk-based testing should be used to focus test efforts.
What does early testing accomplish?
Early testing saves time and money.
Defects that are removed early in the process will not cause subsequent defects in derived work products. The cost of quality will be reduced since fewer failures will occur later in the SDLC
Do defects cluster together or spread out?
Defects cluster together.
A small number of system components usually contain most of the defects discovered or are responsible for most of the operational failures.
This phenomenon is an illustration of the Pareto principle.
Why should you not re-use the same tests too much?
Tests wear out.
If the same tests are repeated many times, they become increasingly ineffective in detecting new defects. This is also known as the pesticide paradox.
How can we overcome the pesticide paradox (Tests wear out)?
To overcome this effect, existing tests and test data may need to be modified, and new tests may need to be written.
Are testing methods and approaches universal?
Testing is context dependent. There is no single universally applicable approach to testing. Testing is done differently in different contexts.
Thoroughly testing all the specified requirements and fixing all the defects found could still produce a system that does what?
A system that meets all specified requirements could still not fulfill the users’ needs and expectations, not help in achieving the customer’s business goals, and be inferior compared to other competing systems. This is the Absence-of-defects fallacy.
