add unittests for converting to utf8
add unittests for converting to utf8

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