Explain the concept of pairwise testing and its application in software quality assurance.

Pairwise testing is a test design method where all possible pairs of parameter values are tested, rather than all possible combinations. This significantly reduces the number of tests while maintaining a high probability of detecting defects related to the interaction of two parameters.

Application:

• When the number of parameters and their values is large, and full enumeration is impossible.
• For effective coverage of interactions between parameters.

For example, if there are 3 parameters with 3 values each, full enumeration would require 27 tests, while pairwise coverage might require about 9 tests.