fix get_metadata test to use getattribute, and expand coverage
fix get_metadata test to use getattribute, and expand coverage

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