HDFS-8826 added an option -source to specify the source node list so that balancer only selects blocks to move from those nodes. This is very efficient in some cases. It also added a new test, testMinBlockSizeAndSourceNodes.
However, testMinBlockSizeAndSourceNodes does not test -source option parsing, for both valid and invalid cases. It builds the parameters directly instead of parsing them from CLI. This JIRA is to track the effort of changing the test for that. In fact, we can refactor the existing code by replacing code that manually creates BalancerParameters with new code that explores the Balancer$Cli#parse().
Thanks jingzhao for the initial proposal.