t3419-*.sh: Fix arithmetic expansion syntax error

diff --git a/t/t7810-grep.sh b/t/t7810-grep.sh
index 8a6322765c965bfc3a9158cc14312fdf03295090..023f225a4b1f22c66fb291a76690564696d56035 100755 (executable)
--- a/t/t7810-grep.sh
+++ b/t/t7810-grep.sh
@@ -65,7 +65,7 @@ do
 
        test_expect_success "grep -w $L (w)" '
                : >expected &&
-               ! git grep -n -w -e "^w" >actual &&
+               test_must_fail git grep -n -w -e "^w" >actual &&
                test_cmp expected actual
        '