def _get_font_files(self):
        """Returns list of font files that should be used by the test."""
        # TODO(sergeyu): Currently FONT_FILES is valid only on Linux. Make it
        # usable on other platforms if necessary.
        result = []
        for (font_dirs, font_file, package) in FONT_FILES:
            exists = False
            for font_dir in font_dirs:
                font_path = self._filesystem.join(font_dir, font_file)
                if not self._filesystem.isabs(font_path):
                    font_path = self._build_path(font_path)
                if self._check_file_exists(font_path, '', more_logging=False):
                    result.append(font_path)
                    exists = True
                    break
            if not exists:
                message = 'You are missing %s under %s.' % (font_file,
                                                            font_dirs)
                if package:
                    message += ' Try installing %s. See build instructions.' % package

                _log.error(message)
                raise TestRunException(exit_codes.SYS_DEPS_EXIT_STATUS,
                                       message)
        return result