am: read from the right mailbox when started from a subdirectory

diff --git a/t/t4020-diff-external.sh b/t/t4020-diff-external.sh
index ed3bd5b3fe7c8b5ca52067e3015e0d770ee79bf2..888293361d4ec39e389b321493dac8ed08886d7c 100755 (executable)
--- a/t/t4020-diff-external.sh
+++ b/t/t4020-diff-external.sh
@@ -99,7 +99,7 @@ test_expect_success 'no diff with -diff' '
        git diff | grep Binary
 '
 
-echo NULZbetweenZwords | tr Z '\0' > file
+echo NULZbetweenZwords | tr Z '\000' > file
 
 test_expect_success 'force diff with "diff"' '
        echo >.gitattributes "file diff" &&