test_access() examines EML metadata for the presence of
a access information in additonalMetadata. The function fails with an
error if access information does not exist. The function passes with a
warning if the access information exists but is deprecated. The
function fails with an error if the information exists but is invalid.
The function passes with a warning if the access is correct but not public.
The function passes without a warning if a current, valid public access
statement exists.
Usage
test_access(metadata = load_metadata(directory))