$mime->header_set('Message-ID', '<b@example.com>');
$mime->header_set('Subject', 'msg2');
-like($im->add($mime), qr/\A:\d+\z/, 'added 2nd message');
+like($im->add($mime, sub { $mime }), qr/\A:\d+\z/, 'added 2nd message');
$im->done;
@revs = $git->qx(qw(rev-list HEAD));
is(scalar @revs, 2, '2 revisions exist');
is($msg->header('Message-ID'), '<a@example.com>', 'Message-ID matches');
isnt($msg->header('Subject'), $mime->header('Subject'), 'subject mismatch');
+$mime->header_set('Message-Id', '<failcheck@example.com>');
+is($im->add($mime, sub { undef }), undef, 'check callback fails');
+is($im->remove($mime), undef, 'message not added, so not removed');
+
$im->done;
done_testing();