send-email: add test for Linux's get_maintainer.pl

We had a regression that broke Linux's get_maintainer.pl. Using
Mail::Address to parse email addresses fixed it, but let's protect
against future regressions.

Note that we need --cc-cmd to be relative because this option doesn't
accept spaces in script names (probably to allow --cc-cmd="executable
--option"), while --smtp-server needs to be absolute.

Patch-edited-by: Matthieu Moy <git@matthieu-moy.fr>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Matthieu Moy <git@matthieu-moy.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t9001-send-email.sh

@@ -172,6 +172,25 @@ test_expect_success $PREREQ 'cc trailer with various syntax' '
 	test_cmp expected-cc commandline1
 '
 
+test_expect_success $PREREQ 'setup fake get_maintainer.pl script for cc trailer' "
+	write_script expected-cc-script.sh <<-EOF
+	echo 'One Person <one@example.com> (supporter:THIS (FOO/bar))'
+	echo 'Two Person <two@example.com> (maintainer:THIS THING)'
+	echo 'Third List <three@example.com> (moderated list:THIS THING (FOO/bar))'
+	echo '<four@example.com> (moderated list:FOR THING)'
+	echo 'five@example.com (open list:FOR THING (FOO/bar))'
+	echo 'six@example.com (open list)'
+	EOF
+"
+
+test_expect_success $PREREQ 'cc trailer with get_maintainer.pl output' '
+	clean_fake_sendmail &&
+	git send-email -1 --to=recipient@example.com \
+		--cc-cmd=./expected-cc-script.sh \
+		--smtp-server="$(pwd)/fake.sendmail" &&
+	test_cmp expected-cc commandline1
+'
+
 test_expect_success $PREREQ 'setup expect' "
 cat >expected-show-all-headers <<\EOF
 0001-Second.patch