* test: `require_unless_one` with second argument
Add the `require_unless_one_2` test. This tests that when the second
argument in the array is used at the command line, that the required
argument is not present. This test was added because it appears the
`require_unless_one` function only works for the first argument in the
array.
* Fix: assertions for test
The assertions did not check for the `infile` to be present.
