I believe this may be fixed in the following commit. I'll include it in the next release, which I hope to happen soon.
commit 20d1dce836f7ecba7ae4cbb0449fa4540e1c6e92
Author: Rocco Caputo <rcaputo@cpan.org>
Date: Mon Jul 15 02:24:41 2013 -0400
Remove a TestServer shutdown race condition.
Counted after 14 cpantesters.org failures of the form "Failed test
'first request honored asynchronously'". Added detailed error
information to the failure. If it happens again, I'll be better
prepared to fix it.
Stopped relying on the order of first/second connection callbacks.
Previously, if the second fired first, we'd shut down the TestServer
too early. The first connection would then fail because.
Meanwhile, always shutdown the connection manager (not just after the
second response). Each session has its own, and they both need to go.
Otherwise the program waits the obligatory connection pool timeout.
