public function testListCoupons()
{
$duration = 'once';
$percentOff = 50;
$request = $this->coupons->createCouponRequest($duration)->setPercentOff($percentOff);
$createResponse = $this->coupons->createCoupon($request);
$request = new ListRequest();
$request->setLimit(1);
$listResponse = $this->coupons->listCoupons($request);
$this->assertInstanceOf(Coupons::LIST_COUPONS_RESPONSE_CLASS, $listResponse);
$this->assertEquals(1, sizeof($listResponse->getData()));
$this->client->delete('coupons/' . $createResponse->getId());
}