From CALLER@myhost.test.ex Tue Mar 02 09:44:33 1999
Received: from CALLER (helo=test.ex)
	by myhost.test.ex with local-esmtp (Exim x.yz)
	(envelope-from <CALLER@myhost.test.ex>)
	id 10HmaX-0005vi-00
	for userx@test.ex; Tue, 2 Mar 1999 09:44:33 +0000
From: Test person <tp@cam.ac.uk>
To: Me <userx@test.ex>
Subject: A real test message
Date: Tue, 2 Mar 1999 09:44:33 +0000
Message-ID: <41C2F849.3060203@projectile.test.ex>
Sender: CALLER_NAME <CALLER@myhost.test.ex>

OK, this should look like a genuine message.

From CALLER@myhost.test.ex Tue Mar 02 09:44:33 1999
Received: from CALLER (helo=test.ex)
	by myhost.test.ex with local-esmtp (Exim x.yz)
	(envelope-from <CALLER@myhost.test.ex>)
	id 10HmaY-0005vi-00
	for userx@test.ex; Tue, 2 Mar 1999 09:44:33 +0000
From: Test person <tp@cam.ac.uk>
To: Me <userx@test.ex>
Subject: A real test message
Date: Tue, 2 Mar 1999 09:44:33 +0000
Message-ID: <41C2F849.3060203@projectile.test.ex>
FakeReject: test fakereject
Sender: CALLER_NAME <CALLER@myhost.test.ex>
X-Regex: Regex matched <THIS gazornenplaz REGEX> <gazornenplaz>

OK, this should look like a genuine message, but
it will trip on THIS gazornenplaz REGEX.