In module Test§

See primary documentation in context for sub dies-ok

multi sub dies-ok(Callable $code$reason = '')

Marks a test as passed if the given $code throws an exception.

The function accepts an optional description of the test.

sub saruman(Bool :$ents-destroy-isengard{
    die "Killed by Wormtongue" if $ents-destroy-isengard;
}
 
dies-ok { saruman(ents-destroy-isengard => True}"Saruman dies";