Test the server with the delta sharing client

[matar993]

wip testing queryTable using a spark-shell with the delta-sharing-spark connector

[tmnd1991]

In order to run the test (that we run through spark-shell last Friday) I suggest you to create a separate gradle module, make it depend on the app and run the app as a simple jar (https://stackoverflow.com/questions/20728621/running-an-executable-jar-file-built-from-a-gradle-based-project). Then you can write a test using spark (i.e. the test is a spark project), having a class path completely separated from the server one.

[tmnd1991]

Very good first step, I think to complete we need:

• add needed gradle code to start the server before running the test
• add needed gradle code to stop the server at the end of the tests
• run these tests on (a dedicated step of) CI

[tmnd1991]

Overall a very good job, a couple of points not pointed out in comments:

• you can generate the http client used in the integration tests starting from the openapi spec, it support java native http client as well (the one you used) that should reduce code duplication and avoid maintenance burden
• you can share a bit more "build side" in this new module (through the internal plugin)