public function testQuery()
{
$exp1 = new Expression();
$exp1->whereGreater('b', 1);
$exp2 = new Expression();
$exp1->whereLess('b', 20);
$query = $this->collection->find();
$query->query($exp1);
$query->query($exp2);
$this->assertEquals(array('b' => array('$gt' => 1, '$lt' => 20)), $query->getMongoQuery());
}