public function testWriteAndReadNullMulti()
{
$expiry = '+1 minute';
$keys = array('key1' => null, 'key2' => 'data2');
$result = $this->Apc->write($keys);
$this->assertTrue($result);
$expected = $keys;
$result = $this->Apc->read(array_keys($keys));
$this->assertEqual($expected, $result);
$keys = array('key1' => null, 'key2' => null);
$result = $this->Apc->write($keys);
$this->assertTrue($result);
}