Concept: Quality Dimensions
Experts generally recognize several distinct dimensions of quality that vary in importance depending on the context in which a QA effort takes place. These dimensions provide a useful framework that helps to define, analyze, and measure the extent to which QA standards, policies and procedures are being met.
Main Description

We can categorize quality using the FURPS+ model [GRA92 -  Robert Grady 1992. Practical Software Metrics for Project Management and Process Improvement. Prentice-Hall]:

  • Functionality
  • Usability
  • Reliability
  • Performance
  • Supportability
  • + (and others)

This is the same categorization scheme that could be used for requirements.

For each of these dimensions, one or more individual types of tests should be implemented and executed during one or more of the different levels of test.