def create_report(self):
        """Generate json dumped report for coveralls api."""
        data = self.create_data()
        try:
            json_string = json.dumps(data)
        except UnicodeDecodeError as e:
            log.error('ERROR: While preparing JSON:', exc_info=e)
            self.debug_bad_encoding(data)
            raise

        log_string = re.sub(r'"repo_token": "(.+?)"',
                            '"repo_token": "[secure]"', json_string)
        log.debug(log_string)
        log.debug('==\nReporting %s files\n==\n', len(data['source_files']))
        for source_file in data['source_files']:
            log.debug('%s - %s/%s', source_file['name'],
                      sum(filter(None, source_file['coverage'])),
                      len(source_file['coverage']))
        return json_string
Generate json dumped report for coveralls api.