Correcting endpoint formatting.

[jameskbride]

Context

The endpoint for each subscription was not rendering correctly in the responses because we were URL encoding the value. This caused endpoints to render in the URL encoded format instead of the expected unencoded format. Because the response is an XML response we need to encode & characters as & instead of URL encoding the entire endpoint.

Changes

• Added an xmlEncodedEndpointUrl() method to the Subscription data class.
• Updated responses which include the endpoint value (ListSubscriptions, ListSubscriptionsByTopic, GetSubscriptionAttributes) to use the XML-encoded endpoint url.

Testing and Validation Steps

1. Create a subscription with an endpoint that includes an & character.
2. Run aws sns list-subscriptions --endpoint-url http://localhost:9911.
3. Validate that the subscription endpoint renders correctly with the &.
4. Run aws sns get-subscription-attributes --endpoint-url http://localhost:9911 --subscription-arn <subscription-arn>.
5. Validate that the subscription endpoint renders correctly with the &.
6. Run aws sns list-subscritptions-by-topic --endpoint-url http://localhost:9911 --topic-arn <subscription topic arn>.
7. Validate that the subscription endpoint renders correctly with the &.