Ergo\Http\QueryString::__toString PHP Method

    function __toString()
    {
        return http_build_query($this->toArray());
    }

 public function testAddParameters()
 {
     $source = "key1=1&key2=2";
     $qs = new Http\QueryString($source);
     $qs->addParameters(array('key2' => 3, 'key3' => 2));
     $this->assertEquals($qs->key2, 3);
     $this->assertEquals("key1=1&key2=3&key3=2", $qs->__toString());
 }