test.pl

# Sequential non-blocking selects
$db = $pg->db;
($fail, $result) = ();
Mojo::IOLoop->delay(
  sub {
    my $delay = shift;
    $db->query('select 1 as one' => $delay->begin);
  },
  sub {
    my ($delay, $err, $one) = @_;
    $fail = $err;
    push @$result, $one->hash;
    $db->query('select 2 as two' => $delay->begin);
  },
  sub {
    my ($delay, $err, $two) = @_;
    $fail ||= $err;
    push @$result, $two->hash;
  }
)->wait;
ok !$fail, 'no error';
is_deeply $result, [{one => 1}, {two => 2}], 'right structure';