Hello, I'd like to push https://issues.apache.org/jira/browse/CALCITE-2185 futher by adding more tests to the Spark adapter, this time using external data sources.
I am familiar with accessing external data from Spark in a Spark application (CSV, JDBC etc.), but I don't know how this could be achieved with the existing test environment in Calcite. I had a look at the existing test suites for other adapters, but they were of no help, as they are aiming at loading data, and not at using other data sources (that is my target now). Did I miss something and any existing tests for other adapters could be re-used? If no, any suggestions on how to set external data sources to be used in Spark tests? PS: if you agree that this new test addition is beneficial, shall I open a new JIRA case for it? Best regards, Alessandro
