Just a comment on testing strategy:

While I like the idea of these sorts of end to end integration tests, I think our goal should be to have a small number of these for smoke testing and regression testing, with the majority of our tests done at the NDC level (ie. issue NDC requests and assert against NDC responses) using ndc-test.

This decouples our tests from the engine, which is useful when developing features that the engine doesn't yet support, simplifies the tests a lot (no metadata required), and also isolates our tests from breaking changes in the engine (less important, since this is not supposed to happen much). It also focuses our testing investment into ndc-test which can be used by any connector to implement snapshot-style testing. We have failed to do this so far, with every connector either not doing testing or rolling their own testing setup. It would be good to see investment in testing be share-able across connectors, though I know that will take some upfront time and investment. cc @codedmart

@hallettj I agree with @daniel-chambers here. These are great, but I do want to use them less and for the reasons @daniel-chambers listed above. We should put more emphasis on ndc-test.