After attempt to implement the mockserver separately, deploy it to Wendy and test it there (that didn't end up well - I hit a few issues that would make the integration testing ineffective:
1. Long mockserver response time - I did not have this kind of issue when testing it locally, not sure what causes this
2. Random java.io.IOException: Connection reset by peer exceptions I couldn't really resolve easily
)

After discussion with Adam Saleh I've decided to implement some sort of integration testing of our sdks in a following way:
1. Implement a simple integration test(s) in android/ios sdks to call /metrics endpoint with (in)valid data in json
2. Run this test on Wendy together with https://github.com/aerogear/aerogear-metrics-api running in a separate container

Wdyt about this approach Peter Braun, David Martin?