Test the random number generator.
This function checks that the
RNG is working properly and has not been changed. If the RNG does not return
values as in previous versions of R then the function executes
stop(). Since changes to the RNG will cause comparisons of
simulation results to fail, this is a useful check before investigating more
complicated problems that may be a result of other "improvements" in your
simulation or estimation programs.
stop() if the tests fail.