For Type::Tiny I had these functions should_pass and should_fail along the lines of:

sub should_pass {
  my ($value, $constraint) = @_;
  ok( $constraint->check($value) );
}
sub should_fail {
  my ($value, $constraint) = @_;
  ok( not $constraint->check($value) );
}

should_pass(2222222, Int);
should_fail(3.14159, Int);
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Because the functions were copied-and-pasted into several different files, I factored them out into a .pm file in the "t" directory, then eventually renamed it Test::TypeTiny, documented it and moved it into "lib", so that it's a reusable testing module for people creating Type::Tiny-based type libraries.

Having these functions in one place instead of scattered about has allowed me to make improvements to them which benefit the entire test suite. For example, recently I added a "pedantic mode" which is triggered by $ENV{EXTENDED_TESTING}.