tests: Add tests for missing format-patch long options

Exercise format-patch's --signoff, --in-reply-to and --start-number long
options.

Signed-off-by: Stephen Boyd <bebarino@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t4014-format-patch.sh

@@ -505,4 +505,15 @@ test_expect_success 'format-patch from a subdirectory (3)' '
 	test -f "$basename"
 '
 
+test_expect_success 'format-patch --in-reply-to' '
+	git format-patch -1 --stdout --in-reply-to "baz@foo.bar" > patch8 &&
+	grep "^In-Reply-To: <baz@foo.bar>" patch8 &&
+	grep "^References: <baz@foo.bar>" patch8
+'
+
+test_expect_success 'format-patch --signoff' '
+	git format-patch -1 --signoff --stdout |
+	grep "^Signed-off-by: $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL>"
+'
+
 test_done

t/t4021-format-patch-numbered.sh

@@ -108,4 +108,10 @@ test_expect_success 'format.numbered = auto && --no-numbered' '
 
 '
 
+test_expect_success '--start-number && --numbered' '
+
+	git format-patch --start-number 3 --numbered --stdout HEAD~1 > patch8 &&
+	grep "^Subject: \[PATCH 3/3\]" patch8
+'
+
 test_done