Why is Testing Necessary?

Testing is necessary to detect the defects, to improve the quality, to make the system more reliable

- People make mistakes or errors.
- Errors made can cause faults or defects.
- Defects can cause failures.
- Failures can cause a big problem.
- Product or deliverable can end up to be defective.
- Perfection is very difficult.

Since nobody is perfect and we always make mistakes, any errors created within the system development life cycle can lead to so many faults within the software, which will eventually lead to the failure of the software.

Error – Mistake made by human.

Fault – The result of an error also known as bugs or defects.

Failure – The result of the fault. This leads to the deviation of the software from its expected results.

If a system has been well tested to the agreed specification, the result should be a reliable system that does what the user requires it to do.

Generally, the more faults or defects that are detected and corrected the more reliable the system will be.
It is also important that the testing carried out reflects the real use of the system.