Discovered a bug in Test::WWW::Mechanize, at least using the Catalyst framework.
ok($mech->put(),"returns true, though the RESTful PUT fails!");
$mech->put_ok($put, "returns false, though the RESTful PUT succeeds!?");
This bug really degrades the quality of TAP as any subsequent tests within a subtest are skipped on failure. Futher, the $mech->put() failure proscribes a work-around. More research for me, for sure.