Constrained-random testing
Beginner
Letting the computer make up tests by rolling dice, with rules so every test still makes sense.
Novice
Tests whose inputs the computer picks at random, within rules (constraints) that keep them legal, such as “the length is between 1 and 64.” A starting number called the seed fixes the random sequence, so rerunning the same seed replays a failure exactly.
Expert
A constraint solver picks legal values. Weights and ordering controls in the test language decide how often each kind of case comes up, and coverage reports show engineers where to adjust them.
Explained in Verification (Design Flow).
See also: Directed test, Functional coverage.