t/repobrowse_git_httpd.t: ensure signature exists for split

I've started using "format.signature=" for an empty signature
on some of my machines to save a few lines.

1 files changed, 3 insertions, 2 deletions

diff --git a/t/repobrowse_git_httpd.t b/t/repobrowse_git_httpd.t
index 3e52b1b5..005ab173 100644
--- a/t/repobrowse_git_httpd.t
+++ b/t/repobrowse_git_httpd.t
@@ -88,9 +88,10 @@ test_psgi(uri => $uri, client => sub {
 
         # ignore signature from git-format-patch:
         my ($patch, undef) = split(/\n-- \n/s, $res->content);
+
+        my $cmd = 'format-patch --signature=git -1 -M --stdout HEAD';
         my ($exp, undef) = split(/\n-- \n/s,
-                `cd "$test->{git_dir}" && \
-                 git format-patch -1 -M --stdout HEAD`);
+                `git --git-dir=$test->{git_dir} $cmd`);
         is($patch, $exp, 'patch content matches expected');
 });