t1400 (update-ref): use test_must_fail

diff --git a/t/t1200-tutorial.sh b/t/t1200-tutorial.sh
index ab55eda158bb5a6ecad77302aa2fe17bd6e92be3..bfa2c2190d0368eba533a8411df739eee77fa1be 100755 (executable)
--- a/t/t1200-tutorial.sh
+++ b/t/t1200-tutorial.sh
@@ -42,7 +42,7 @@ test_expect_success 'git diff' '
 '
 
 test_expect_success 'tree' '
-       tree=$(git write-tree 2>/dev/null)
+       tree=$(git write-tree 2>/dev/null) &&
        test 8988da15d077d4829fc51d8544c097def6644dbb = $tree
 '