Components of Quality Assurance

Most software quality assurance activities can be categorized into software testing (that is, verification and validation), software configuration management, and quality control. However, the success of a software quality assurance program also depends on a coherent collection of standards, practices, conventions, and specifications, as shown in Figure below.

Software testing is a popular risk management strategy. It is used to verify that functional requirements were met. The limitation of this approach, however, is that by the time testing occurs, it is too late to build quality into the product. Tests are only as good as the test cases, but they can be inspected to ensure that all the requirements are tested across all possible combinations of inputs and system states. However, not all defects are discovered during testing. Software testing includes the activities outlined in this text, including verification and validation activities. In many organizations, these activities, or their supervision, are included within the charter for the software quality assurance function. The extent to which personnel independent of design and coding should participate in software quality assurance activities is a matter of institutional, organizational, and project policy.

The major purpose of verification and validation activities is to ensure that software design, code, and documentation meet all the requirements imposed on them. Examples of requirements include user requirements; specifications derived from and designed to meet user requirements; code review and inspection criteria; test requirements at the modular, subsystem, and integrated software levels; and acceptance testing of the code after it has been fully integrated with hardware.

During software design and implementation, verification helps determine whether the products of one phase of the software development life cycle fulfill the requirements established during the previous phase. The verification effort takes less time and is less complex when conducted throughout the development process.