:; time make test
PERL_DL_NONLAZY=1 /usr/bin/perl "-MExtUtils::Command::MM" "-e" "test_h
+arness(0, 'blib/lib', 'blib/arch')" t/*.t
t/01-conversion_0_10000................ok           
t/02-conversion_10001_999999...........ok       
t/03-conversion_1000000_and_up.........ok     
t/04-special-cases.....................ok   
t/71-version_numbers_are_the_same......ok   
t/pod-coverage.........................ok   
t/pod..................................ok   
All tests successful.
Files=7, Tests=10218,  7 wallclock secs ( 0.94 usr  0.15 sys +  6.70 c
+usr  0.14 csys =  7.93 CPU)
Result: PASS

real    0m7.180s
user    0m7.726s
sys    0m0.324s
[download]

There you go, over 10k tests in just 7 seconds.

Granted, that is not a full system, just a module. However, my answers remain: my largest test suite has over 10000 tests, and it runs in just a few seconds.

I also recall creating a system with ~400 tests that would run in just no time. Then again, the most enforced requisite of that platform was that it had to process over 1000 requests per second.

And it did.