public function testGetCoupon()
 {
     $createResponse = $this->createCoupon();
     $this->assertInstanceOf(Coupons::COUPON_RESPONSE_CLASS, $createResponse);
     $getResponse = $this->coupons->getCoupon($createResponse->getId());
     $this->assertInstanceOf(Coupons::COUPON_RESPONSE_CLASS, $getResponse);
     $this->assertEquals($createResponse->getId(), $getResponse->getId());
     $this->client->delete('coupons/' . $createResponse->getId());
 }