The source files are tut3.tv, and counter1.v or counter1.vhd. tut3.tv is simply a "safer" version of tut2.tv, which may be considered to be more appropriate for large testbenches. The use of implicit variables is disabled, and two variables are instead explicitly declared. The program also enables a higher level of type safety, which enforces a restriction that the 4-bit DUT ports can only be driven with, or tested against, 4-bit expressions. These are the defaults when the program does not explicitly change the value of the _StrictChecking pragma.
The expected output is:
(Log) (200 ns) 20 vectors executed (20 passes, 0 fails)