commit_msg_is "standard input msg"
'
+test_expect_success 'using alternate GIT_INDEX_FILE (1)' '
+
+ cp .git/index saved-index &&
+ (
+ echo some new content >file &&
+ GIT_INDEX_FILE=.git/another_index &&
+ export GIT_INDEX_FILE &&
+ git add file &&
+ git commit -m "commit using another index" &&
+ git diff-index --exit-code HEAD &&
+ git diff-files --exit-code
+ ) &&
+ cmp .git/index saved-index >/dev/null
+
+'
+
+test_expect_success 'using alternate GIT_INDEX_FILE (2)' '
+
+ cp .git/index saved-index &&
+ (
+ rm -f .git/no-such-index &&
+ GIT_INDEX_FILE=.git/no-such-index &&
+ export GIT_INDEX_FILE &&
+ git commit -m "commit using nonexistent index" &&
+ test -z "$(git ls-files)" &&
+ test -z "$(git ls-tree HEAD)"
+
+ ) &&
+ cmp .git/index saved-index >/dev/null
+
+'
+
test_done