A system and method for testing functionality of an application for compatibility with a foreign character set (e.g., a character set other than a "native" or original character set of the application). Input or output of a master test case designed to test the functionality of the application is converted or mapped to the foreign character set. The mapped test case is then executed or otherwise used to test the application functionality and a log file or output is collected. The log file is mapped back to the native character set and compared to expected test results. Prior to testing, the size of a buffer or data structure used in the testing may be altered according to the character size of the foreign character set, and contents of a database used for testing may be converted to the foreign character set.