It's all good, we were all new at some point
Here is what I would do for the tests:
Developer Guide is a really good link to read on how unit tests work in Hive:
Practically, unit tests take a long time to run on especially if you run it on 1 node (like me), so for a minor change like this, I run only the tests that are impacted.
To figure that out what's impacted, I would do something like:
grep -ri "hour" *
For results under clientpositive, I would run something like:
ant test -Dtestcase=TestCliDriver -Dqfile=<comma separated list of .q files>
For results under clientnegative, I would run something like:
ant test TestNegativeCliDriver -Dqfile=<comma separated list of .q files>
If any of the above tests fail, it may legitimately be because of the bug fix, in which case, you would want to update the test output. You can do that by using -Doverwrite=true at the end of your commands. If the outputs, do need to get updated, please include those diffs in the patch as well.
The committers would usually run the whole suite of tests (some times on faster clusters), so don't be paranoid about testing all tests but of course, do you due-diligence about finding all tests that may be impacted and making sure they run fine.
Hope this makes sense. If you have any further questions, please don't hesitate to ask. And, thanks for working on this patch!