Hey Inertia,
Since our APIs are going to change rapidly I would not advise trying to test against them.
Instead, we have a testing mechanism that generates language outputs based on JSON test data and serializes it back out to binary/JSON. It then compares the outputs of each language. This is how you could check the correctness of your implementation.
See:
https://github.com/koinos/koinos-types/blob/master/ci/test.sh#L17
We also run basic unit tests against each language individually, you can see examples of that in the test directory.
Thanks for contributing!