Software Testing - core principles of software testing

The core principles of software testing are widely recognized guidelines that help ensure testing is effective and efficient. Here are the main ones:

1. Testing shows the presence of defects, not their absence

• Testing can prove bugs exist, but it can’t guarantee the software is completely error-free.

2. Exhaustive testing is impossible

• It’s impractical to test all inputs, paths, and scenarios; testing must be focused and prioritized.

3. Early testing saves time and cost

• Detecting and fixing defects early in the development lifecycle is cheaper and easier.

4. Defects cluster together

• A small number of modules often contain the majority of bugs, so testing should focus more on high-risk areas.

5. The pesticide paradox

• Running the same tests repeatedly finds fewer new defects over time; test cases need to be reviewed and updated.

6. Testing is context-dependent

• The testing approach varies based on the type of software, its risks, and its usage (e.g., safety-critical vs. web app).

7. Absence-of-errors fallacy

• A defect-free system is useless if it doesn’t meet the user’s needs and expectations.