num_method_tests() doesn’t work outside test module

[FGasper]

#!perl

use strict;
use warnings;

use Test::More;

package t::Base;

use base 'Test::Class';

sub mytest : Tests(2) {
}

package main;

is( t::Base->num_method_tests('mytest'), 2, 'num_method_tests()' );

done_testing();

This breaks with:

> prove -wlvm t/inheritance_count.t
t/inheritance_count.t ..
not called in a Test::Class at t/inheritance_count.t line 17.
Dubious, test returned 255 (wstat 65280, 0xff00)
No subtests run

Test Summary Report
-------------------
t/inheritance_count.t (Wstat: 65280 Tests: 0 Failed: 0)
  Non-zero exit status: 255
  Parse errors: No plan found in TAP output
Files=1, Tests=0,  0 wallclock secs ( 0.02 usr  0.01 sys +  0.04 cusr  0.00 csys =  0.07 CPU)
Result: FAIL

I’m not sure if this is fixable, but it‘s at least worth reporting.