public function testWriteExpiryDefault()
{
$xCache = new XCache(array('expiry' => '+5 seconds'));
$key = 'default_key';
$data = 'value';
$keys = array($key => $data);
$time = strtotime('+5 seconds');
$result = $xCache->write($keys);
$this->assertTrue($result);
$expected = $data;
$result = xcache_get($key);
$this->assertEqual($expected, $result);
$result = xcache_unset($key);
$this->assertTrue($result);
}