test_expect_success 'pre-receive hook input' '
        (echo $commit0 $commit1 refs/heads/master;
         echo $commit1 $commit0 refs/heads/tofail
-       ) | git diff - victim/.git/pre-receive.stdin
+       ) | test_cmp - victim/.git/pre-receive.stdin
 '
 
 test_expect_success 'update hook arguments' '
        (echo refs/heads/master $commit0 $commit1;
         echo refs/heads/tofail $commit1 $commit0
-       ) | git diff - victim/.git/update.args
+       ) | test_cmp - victim/.git/update.args
 '
 
 test_expect_success 'post-receive hook input' '
        echo $commit0 $commit1 refs/heads/master |
-       git diff - victim/.git/post-receive.stdin
+       test_cmp - victim/.git/post-receive.stdin
 '
 
 test_expect_success 'post-update hook arguments' '
        echo refs/heads/master |
-       git diff - victim/.git/post-update.args
+       test_cmp - victim/.git/post-update.args
 '
 
 test_expect_success 'all hook stdin is /dev/null' '
 EOF
 test_expect_success 'send-pack stderr contains hook messages' '
        grep ^STD send.err >actual &&
-       git diff - actual <expect
+       test_cmp - actual <expect
 '
 
 test_done