Priniciple of Software Testing and Difference between QC and QA

Basics of Testing

Testing is a quality control activity with objectives as finding defects, gaining confidence on the quality of products and preventing defect. Testing should start as early as possible and should be planned for different phases of software life cycle. Early detection of defects reduces the cost of fixing defects.

Principles of Testing

Below are the principles of testing which should be taken into consideration while performing testing:

• Testing shows presence of defect but we cannot ensure there are no defects in the system. The reason for this is described in next principle

• Exhaustive testing is not possible as covering all combination of data and scenario is not feasible as it will take lot of cost and resources & time.

• Testing Activity should start as soon as possible. This will result in defect fixed with less effort in development and development can more easily accommodate the changes in early phases than latter.

• So now the question arises, which things to test first. Most of the defects are concentrated to small number of modules, which is defect clustering. So we need to concentrate more on modules more prone to defects.

• Next test case needs to be updated regularly to avoid pesticide paradox i.e same test cases if executed again and again will not be able to find more defects.

• Testing should be context sensitive, i.e before considering testing, we should take into consideration the impact and importance area of the application

• And finally the product delivered and tested should match the client expectation, and is no purpose even if no defect is found, but product does not fulfill client requirement.

    

 Quality Control and Quality Assurance

Last point in the Testing principles mentions the product delivered to the customer should be quality product. To ensure quality of the product, we must follow quality assurance and quality control activities.

Quality Assurance ensures proper quality processes are followed during product development .For example. There are regular audits, inspections, review activities, estimations, testing process standards during the software life cycle to assure the quality of product.

Quality Control is the testing activities in which product quality is compared with expected standards and issue is raised in case of defects or non conformance being encountered.

Some of the most important Quality Factors are Correctness, Reliability, Efficiency, Integrity, Usability, Maintainability, Reusability, and portability.