Nagios-Plugin-Getopt-03.t automatically tests all cases defined in the 'input' directory and expects the output to match the corresponding file in the 'expected' directory. To define a new test case, just create a new file in the 'input' directory containing the input command line, and a corresponding file in the 'expected' directory containing what you think the expanded command line should be. Note that this expansion is normalised as follows: - command line arguments are reported in alphabetical order - extraneous white space is removed Also, if you use a completely new argument than those currently defined in Nagios-Plugin-Getopt-03.t you will need to define it there as well.