This is in preperation for adding more optional arguments. Adds a
generic get_arg function, tests for it, and converts get_size to use it.
(cherry picked from commit 4a4128af23)
Related: rhbz#1859680
The callers, and the documentation, all expect int 0/1 to use as the
exit status for the program. Not True/False, even though that works most
of the time.
(cherry picked from commit fad9b324f7)
Related: rhbz#1779301
Some results have errors and no status, others have status and errors.
Update the function to return the final rc to exit with, and a bool
indicating whether or not to continue processing the other fields.
Add a bunch of tests for the new function to make sure I have the logic
correct.
(cherry picked from commit 35fa067219)
