Test::Time

Use Test::Scheduler to use on your tests, not only Promises, but sleep, now and time.

my $started = now;
$*SCHEDULER = mock-time :auto-advance;

sleep 10;
say "did it passed { now - $started } seconds?";
unmock-time;

say "No, just passed { now - $started } seconds!";

#`{{{
Output:
    did it passed 10.0016178 seconds?
    No, just passed 0.07388266 seconds!
}}}

Or you can use $*SCHEDULER.advance-by: 10 as you would when using Test::Scheduler