public function testListCollections()
 {
     $ns = $this->object->selectCollection('system.namespaces');
     for ($i = 0; $i < 10; $i++) {
         $c = $this->object->selectCollection("x{$i}");
         $c->insert((object) array("foo" => "bar"), array("safe" => true));
     }
     $list = $this->object->listCollections();
     for ($i = 0; $i < 10; $i++) {
         $this->assertTrue($list[$i] instanceof MongoCollection);
         if (!preg_match("/5\\.1\\../", phpversion())) {
             $this->assertTrue(in_array("phpunit.x{$i}", $list));
         }
     }
 }