test_expect_success 'diff can read from stdin' '
test_must_fail git diff --no-index -- MN - < NN |
- grep -v "^index" | sed "s#/-#/NN#" >.test-a &&
+ sed "/^index/d; s#/-#/NN#" >.test-a &&
test_must_fail git diff --no-index -- MN NN |
grep -v "^index" >.test-b &&
test_cmp .test-a .test-b