Testing terms

What is Testing?
Testing is a process of idetifying defects in a software application.

Why Testing?
Inorder to ensure that product is according to requirements of customer and works fine without any defects.

WhiteBoxTesting:
It is a kind of testing where testers have access to implementation part of the application and examines it for defects. Also called glass/clear box testing or structural testing.

BlackBox testing:
It is a kind of testing where tester knows only the functionality of the system and doesnt know how it works internally.

Static testing:
Code is examined without being executed.
Eg:Code inspections, Reviews and walkthrough

Reviews:
A group of persons look for errors, mistaken assumptions, lack of clarity and deviation from standard practice.
Eg:Review of specifications and project plans.

Walk-through:
Walk-through is similar to review but informal, generally conducted by team members.
Eg:Improving program logic and design approach etc.

Regression Testing:
It is a selective retesting done to detect faults faults during the modification of system.
To verify modifications havenot caused unintended adverse effects.
To ensure that even after modification, system meets the requirements.

Performance Testing:
Performance testing is aimed at verifying if system meets the system's performance requirements like 'response time' and 'transactional throughput'.
Response time: Time taken to deliver expected output.
Throughput: Quantity of output per given time.

Security Testing:
Verifying how easily a system is subjected to security violations under different environments and conditions.


Defect Density:
Defect density is the ratio of no.of. defects detected to the size of software.

Defect density= No.of.defects/size

Here size can be LOC or Function points.

Defect density is uesful to compare quality/no.of.defects of relevant components.
Another use of Defect density is to compare subsequent releases of a product to track defect reduction and quality improvement.