Regression
The running of a suite of tests repeatedly in some cycle, in order to determine forward progress of a design/verification activity, and catch any unexpected backwards progress (regression) so that debug may determine whether a design bug or a verification bug exists, and what needs to be done to move that test to a passing state and continue with forward progress. A regression suite has various attributes - it may require one or more verification environments / testbenches, it may use parameters to alter design or testbench configuration, there may be test stimulus which is directed, or constrained random, or graph-based, and there may be different knobs controlling checks to be performed, amount of debug data to collect, and extent of simulation. Underlying machinery is used to distribute the compilation and running of the various tests on simulators and other tools, often requiring parallel run distribution across multiple compute environments. Underlying machinery can control the intent of the regression (what stimulus to run) and capture the results of that run and/or cumulative runs on order to present data to the verification resources to aid their productivity or their ability to achieve Coverage Closure.
