t1400 (update-ref): use test_must_fail

diff --git a/t/t4015-diff-whitespace.sh b/t/t4015-diff-whitespace.sh
index 935d101fe8d880ff426452ca6f611ce8d30b8bc1..88c6b5bdcbd1df287edfe42bc06804cdb98574f5 100755 (executable)
--- a/t/t4015-diff-whitespace.sh
+++ b/t/t4015-diff-whitespace.sh
@@ -330,7 +330,7 @@ test_expect_success 'check space before tab in indent (space-before-tab: on)' '
 
 test_expect_success 'check spaces as indentation (indent-with-non-tab: off)' '
 
-       git config core.whitespace "-indent-with-non-tab"
+       git config core.whitespace "-indent-with-non-tab" &&
        echo "        foo ();" > x &&
        git diff --check