--- /dev/null
+# Copyright (C) 2017 all contributors <meta@public-inbox.org>
+# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
+use strict;
+use warnings;
+use Test::More;
+use Email::MIME;
+use File::Temp qw/tempdir/;
+use_ok 'PublicInbox::Filter::RubyLang';
+
+my $f = PublicInbox::Filter::RubyLang->new;
+ok($f, 'created PublicInbox::Filter::RubyLang object');
+my $msg = <<'EOF';
+Subject: test
+
+keep this
+
+Unsubscribe: <mailto:ruby-core-request@ruby-lang.org?subject=unsubscribe>
+<http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>
+EOF
+my $mime = Email::MIME->new($msg);
+my $ret = $f->delivery($mime);
+is($ret, $mime, "delivery successful");
+is($mime->body, "keep this\n", 'normal message filtered OK');
+
+SKIP: {
+ eval 'require DBD::SQLite';
+ skip 'DBD::SQLite missing for altid mapping', 4 if $@;
+ use_ok 'PublicInbox::Inbox';
+ my $git_dir = tempdir('pi-filter_rubylang-XXXXXX',
+ TMPDIR => 1, CLEANUP => 1);
+ is(mkdir("$git_dir/public-inbox"), 1, "created public-inbox dir");
+ my $altid = [ "serial:ruby-core:file=msgmap.sqlite3" ];
+ my $ibx = PublicInbox::Inbox->new({ mainrepo => $git_dir,
+ altid => $altid });
+ $f = PublicInbox::Filter::RubyLang->new(-inbox => $ibx);
+ $msg = <<'EOF';
+X-Mail-Count: 12
+Message-ID: <a@b>
+
+EOF
+ $mime = Email::MIME->new($msg);
+ $ret = $f->delivery($mime);
+ is($ret, $mime, "delivery successful");
+ my $mm = PublicInbox::Msgmap->new($git_dir);
+ is($mm->num_for('a@b'), 12, 'MM entry created based on X-ML-Count');
+
+ $msg = <<'EOF';
+X-Mail-Cout: 12
+Message-ID: <b@b>
+
+EOF
+
+ $mime = Email::MIME->new($msg);
+ $ret = $f->delivery($mime);
+ is($ret, 100, "delivery rejected without X-Mail-Count");
+}
+
+done_testing();