public function test_del()
{
$this->mem->add(__METHOD__ . 'd1', 1);
$call = $this->mem->del(__METHOD__ . 'd1');
$this->assertTrue($call);
$check = $this->mem->read(__METHOD__ . 'd1');
$this->assertTrue(empty($check))->addCommentary('variables still in cache');
$this->mem->add(__METHOD__ . 'd1', 1);
$this->mem->add(__METHOD__ . 'd2', 1);
$call = $this->mem->del(array(__METHOD__ . 'd1', __METHOD__ . 'd2'));
$this->assertTrue($call);
$check = $this->mem->read(array(__METHOD__ . 'd1', __METHOD__ . 'd2'));
$this->assertTrue(empty($check))->addCommentary('variables still in cache: ' . print_r($check, 1));
}