Complete integration tests for the get patient endpoint

[rcrichton]

For this endpoint we need to ensure that the following cases are tested:

• Test with valid message structure and valid message content
  • Test the case where endpoint returns a positive (ie 200 or 201) response
  • Test the case where endpoint returns a negative (ie 404 etc) response
  • Test others cases if the endpoint can respond in other ways ...
• Test with invalid message structure
• Test with valid message structure and invalid message content that would cause specific failure cases in that endpoint. This will be different for each endpoint.