Add tests for git tag

These tests check whether git-tag properly sends a comment into the
editor, and whether it reuses previous annotation when overwriting
an existing tag.

Signed-off-by: Mike Hommey <mh@glandium.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t7004-tag.sh

@@ -1004,4 +1004,20 @@ test_expect_failure \
 	'verify signed tag fails when public key is not present' \
 	'git-tag -v signed-tag'
 
+test_expect_success \
+	'message in editor has initial comment' '
+	GIT_EDITOR=cat git tag -a initial-comment > actual || true &&
+	test $(sed -n "/^\(#\|\$\)/p" actual | wc -l) -gt 0
+'
+
+get_tag_header reuse $commit commit $time >expect
+echo "An annotation to be reused" >> expect
+test_expect_success \
+	'overwriting an annoted tag should use its previous body' '
+	git tag -a -m "An annotation to be reused" reuse &&
+	GIT_EDITOR=true git tag -f -a reuse &&
+	get_tag_msg reuse >actual &&
+	git diff expect actual
+'
+
 test_done