t1400 (update-ref): use test_must_fail

As t/README explains:

	When a gitcommand dies due to a segfault, test_must_fail
	diagnoses it as an error; "! git <command>" treats it as
	just another expected failure, which would let such a bug
	go unnoticed.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/t/t1400-update-ref.sh b/t/t1400-update-ref.sh
index d17551eb724a4deb4e682dcfba5a885d5a839ce2..ff747f8229bb46df070ea9aad2702f4d1c703420 100755 (executable)
--- a/t/t1400-update-ref.sh
+++ b/t/t1400-update-ref.sh
@@ -52,9 +52,8 @@ rm -f .git/$m
 
 test_expect_success \
        "fail to create $n" \
-       "touch .git/$n_dir
-        git update-ref $n $A >out 2>err"'
-        test $? != 0'
+       "touch .git/$n_dir &&
+        test_must_fail git update-ref $n $A >out 2>err"
 rm -f .git/$n_dir out err
 
 test_expect_success \