public function testGetCollected()
 {
     $params = array('other' => 'pickles');
     $url = '/invoices?other=pickles&state=collected';
     $this->client->addResponse('GET', $url, 'invoices/index-200.xml');
     $invoices = Recurly_InvoiceList::getCollected($params, $this->client);
     $this->assertInstanceOf('Recurly_InvoiceList', $invoices);
     $this->assertEquals($url, $invoices->getHref());
 }