rewrite unittests to reflect log error on empty file list
rewrite unittests to reflect log error on empty file list

funginstitute/patentprocessor,nikken1/patentprocessor,nikken1/patentprocessor,funginstitute/patentprocessor,yngcan/patentprocessor,yngcan/patentprocessor,yngcan/patentprocessor,nikken1/patentprocessor,funginstitute/patentprocessor