+my $git = PublicInbox::Git->new($git_dir);
+is('public-inbox 1.0.0',
+ $git->commit_title('cb7c42b1e15577ed2215356a2bf925aef59cdd8d'),
+ 'commit_title works on 1.0.0');
+
+is(undef, $git->commit_title('impossible'), 'undef on impossible object');
+
+$ibx->{-repo_objs} = [ $git ];