01-runner.t

#! perl
use strict;
use warnings;

use Test::Class::Moose::Load 't/lib/';
Test::Class::Moose->new->runtests;

Bar.pm

package Tests::Bar;
use Test::Class::Moose;
extends 'Base::Foo';

has '+foo' => ( default => 'baz' );

sub test_foo :Tests {
  my $test = shift;
  diag "wtf";

  is( $test->foo , 'baz' , 'yay' );
}

1;

Foo.pm

package Base::Foo;
use Moose;

has 'foo' => ( is => 'ro' , isa => 'Str' , required => 1 );

1;

result

% prove -I./t/lib  t/01-runner.t                                                                                                                                                                                                              23:02:10
t/01-runner.t .. You said to run 0 tests at t/01-runner.t line 6.
t/01-runner.t .. Dubious, test returned 255 (wstat 65280, 0xff00)
No subtests run

Test Summary Report
-------------------
t/01-runner.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 ( 0.01 usr  0.00 sys +  0.32 cusr  0.02 csys =  0.35 CPU)
Result: FAIL