Testing Principles

Testing Principles

1. Testing shows presence of defects

   • Testing can show the defects are present but cannot prove that there are no defects. Even after testing the application or product thoroughly, we can not say that the product is 100% defect free.

2. Exhaustive testing is impossible

   • Testing everything including all combinations of inputs and preconditions is not possible. So, instead of doing the exhaustive testing we can use risks and priorities to focus testing efforts.

3. Early testing

   • In the software development life cycle testing activities should start as early as possible and should be focused on defined objectives.

4. Defect clustering

   • A small number of modules contains most of the defects discovered during pre-release testing or shows the most operational failures.

5. Pesticide paradox

   • If the same kinds of tests are repeated again and again, eventually the same set of test cases will no longer be able to find any new bugs.

6. Testingis context dependent

   • Testing is basically context dependent. Different kinds of sites are tested differently. For example, safety –critical software is tested differently from an e-commerce site.

7. Absence of errors fallacy

   • If the system built is unusable and does not fulfil the user’s needs and expectations, then finding and fixing defects does not help.