--- /dev/null
+#!/usr/bin/perl
+use strict;
+use warnings;
+use Test::More qw/no_plan/;
+
+use_ok("RT");
+
+RT::LoadConfig();
+RT::Init();
+
+use RT::Interface::Email;
+
+# normal use case, regexp set to rtname
+$RT::rtname = "site";
+$RT::EmailSubjectTagRegex = qr/$RT::rtname/ ;
+$RT::rtname = undef;
+is(RT::Interface::Email::ParseTicketId("[site #123] test"), 123);
+is(RT::Interface::Email::ParseTicketId("[othersite #123] test"), undef);
+
+# oops usecase, where the regexp is scragged
+$RT::rtname = "site";
+$RT::EmailSubjectTagRegex = undef;
+is(RT::Interface::Email::ParseTicketId("[site #123] test"), 123);
+is(RT::Interface::Email::ParseTicketId("[othersite #123] test"), undef);
+
+# set to a simple regexp. NOTE: we no longer match "site"
+$RT::rtname = "site";
+$RT::EmailSubjectTagRegex = qr/newsite/;
+is(RT::Interface::Email::ParseTicketId("[site #123] test"), undef);
+is(RT::Interface::Email::ParseTicketId("[newsite #123] test"), 123);
+
+# set to a more complex regexp
+$RT::rtname = "site";
+$RT::EmailSubjectTagRegex = qr/newsite||site/;
+is(RT::Interface::Email::ParseTicketId("[site #123] test"), 123);
+is(RT::Interface::Email::ParseTicketId("[newsite #123] test"), 123);
+is(RT::Interface::Email::ParseTicketId("[othersite #123] test"), undef);
+