Add automation test coverage for "union all", by searching through the q-tests in "ql/src/test/queries/clientpositive/" for union tests (like union*.q) and verifying/enabling them on spark.
Steps to do:
1. Enable a qtest <q-test-name>.q in itests/src/test/resources/testconfiguration.properties by adding the .q test files to spark.query.files.
2. Run mvn test -Dtest=TestSparkCliDriver -Dqfile=<q-test-name>.q -Dtest.output.overwrite=true -Phadoop-2 to generate the output (located in ql/src/test/results/clientpositive/spark). File will be called <q-test-name>.q.out.
3. Check the generated output is good by verifying the results. For comparison, check the MR version in ql/src/test/results/clientpositive/<q-test-name>.q.out. The reason its separate is because the explain plan outputs are different for Spark/MR.
4. Checkin the modification to testconfiguration.properties, and the generated q.out file as well. You only have to generate the output once.