+cat > "${MAIL_DIR}"/mbox_file <<EOF
+From test_suite@notmuchmail.org Fri Jan 5 15:43:57 2001
+From: Notmuch Test Suite <test_suite@notmuchmail.org>
+To: Notmuch Test Suite <test_suite@notmuchmail.org>
+Subject: Test mbox message 1
+
+Body.
+
+From test_suite@notmuchmail.org Fri Jan 5 15:43:57 2001
+From: Notmuch Test Suite <test_suite@notmuchmail.org>
+To: Notmuch Test Suite <test_suite@notmuchmail.org>
+Subject: Test mbox message 2
+
+Body 2.
+EOF