public function testClear()
{
$time = strtotime('+1 minute');
$result = $this->_conn->set('key', 'value', $time);
$this->assertTrue($result);
$result = $this->_conn->set('another_key', 'value', $time);
$this->assertTrue($result);
$result = $this->memcache->clear();
$this->assertTrue($result);
$this->assertFalse($this->_conn->get('key'));
$this->assertFalse($this->_conn->get('another_key'));
}