diff --git a/t/t9001-send-email.sh b/t/t9001-send-email.sh
index 3dc4a3454d..f75698016f 100755
--- a/t/t9001-send-email.sh
+++ b/t/t9001-send-email.sh
@@ -6,6 +6,12 @@ test_description='git send-email'
 # May be altered later in the test
 PREREQ="PERL"
 
+replace_variable_fields () {
+	sed	-e "s/^\(Date:\).*/\1 DATE-STRING/" \
+		-e "s/^\(Message-Id:\).*/\1 MESSAGE-ID-STRING/" \
+		-e "s/^\(X-Mailer:\).*/\1 X-MAILER-STRING/"
+}
+
 test_expect_success $PREREQ 'prepare reference tree' '
 	echo "1A quick brown fox jumps over the" >file &&
 	echo "lazy dog" >>file &&
@@ -293,10 +299,7 @@ test_expect_success $PREREQ 'Show all headers' '
 		--bcc=bcc@example.com \
 		--in-reply-to="<unique-message-id@example.com>" \
 		--smtp-server relay.example.com \
-		$patches |
-	sed	-e "s/^\(Date:\).*/\1 DATE-STRING/" \
-		-e "s/^\(Message-Id:\).*/\1 MESSAGE-ID-STRING/" \
-		-e "s/^\(X-Mailer:\).*/\1 X-MAILER-STRING/" \
+		$patches | replace_variable_fields \
 		>actual-show-all-headers &&
 	test_cmp expected-show-all-headers actual-show-all-headers
 '
@@ -551,12 +554,6 @@ Result: OK
 EOF
 "
 
-replace_variable_fields () {
-	sed	-e "s/^\(Date:\).*/\1 DATE-STRING/" \
-		-e "s/^\(Message-Id:\).*/\1 MESSAGE-ID-STRING/" \
-		-e "s/^\(X-Mailer:\).*/\1 X-MAILER-STRING/"
-}
-
 test_suppression () {
 	git send-email \
 		--dry-run \