NOTE: this is the backport to next-mr.
                
This patch addresses the bug reported by checking wether 
host argument is an empty string or not. If empty, an error is
reported to the client, otherwise continue normally.
                       
This commit is based on the originally proposed patch and adds 
a test case as requested during review as well as refines comments, 
and makes test case result file less verbose (compared to previous patch).