public function testToString()
 {
     $discountParams = array("amount" => "100.00", "description" => "some description", "id" => "1", "kind" => "discount", "name" => "php_discount", "neverExpires" => "false", "numberOfBillingCycles" => "1");
     $discount = Braintree\Discount::factory($discountParams);
     $this->assertEquals("Braintree\\Discount[amount=100.00, description=some description, id=1, kind=discount, name=php_discount, neverExpires=false, numberOfBillingCycles=1]", (string) $discount);
 }