tests: show lsof output on deleted-file-check failures

This may help track down some occasional test failures I'm
seeing.

1 files changed, 3 insertions, 2 deletions

diff --git a/t/nntpd.t b/t/nntpd.t
index 7db371dd..ce4d7cf9 100644
--- a/t/nntpd.t
+++ b/t/nntpd.t
@@ -365,8 +365,9 @@ Date: Fri, 02 Oct 1993 00:00:00 +0000
                 $lsof or skip 'lsof missing', 1;
                 ($^O =~ /\A(?:linux)\z/) or
                         skip "lsof /(deleted)/ check untested on $^O", 1;
-                my @of = xqx([$lsof, '-p', $td->{pid}], undef, $noerr);
-                is(scalar(grep(/\(deleted\)/, @of)), 0, 'no deleted files');
+                my @lsof = xqx([$lsof, '-p', $td->{pid}], undef, $noerr);
+                my $d = [ grep(/\(deleted\)/, @lsof) ];
+                is_deeply($d, [], 'no deleted files') or diag explain($d);
         };
         SKIP: { test_watch($tmpdir, $host_port, $group) };
         {