Apparently the Hive tests do not run successfully after a clean unless you run
ant package first. Not sure why build.xml doesn't encode this dependency.
Adding new unit tests
As of version 0.13 Hive uses Maven instead of Ant for its build. The following instructions are not up to date.
First, write a new myname.q in ql/src/test/queries/clientpositive.
Similarly, to add negative client tests, write a new query input file in ql/src/test/queries/clientnegative and run the same command, this time specifying the testcase name as TestNegativeCliDriver instead of TestCliDriver. Note that for negative client tests, the output file if created using the overwrite flag can be be found in the directory ql/src/test/results/clientnegative.
See also Tips for Adding New Tests in Hive.
Debugging Hive Code
Hive code includes both client-side code (e.g., compiler, semantic analyzer, and optimizer of HiveQL) and server-side code (e.g., operator/task/SerDe implementations). Debugging is different for client-side and server-side code, as described below.