test_expect_success 'format-patch --zero-commit' '
git format-patch --zero-commit --stdout v2..v1 >patch2 &&
grep "^From " patch2 | sort | uniq >actual &&
- echo "From $_z40 Mon Sep 17 00:00:00 2001" >expect &&
+ echo "From $ZERO_OID Mon Sep 17 00:00:00 2001" >expect &&
test_cmp expect actual
'