public function testReplaceSessionData() {
$this->storage
->write('foo', 'bar');
$this->storage
->write('foo', 'foobar');
$coll = self::$mongo
->selectDB($this->options['database'])
->selectCollection($this->options['collection']);
$this
->assertEquals('foobar', $this->storage
->read('foo'));
$this
->assertEquals(1, $coll
->find(array(
'sess_id' => 'foo',
))
->count());
}