'Tests an URL for eval() usage vulnerabilities using echo strings.
:param freq: A FuzzableRequest'

def _fuzz_with_echo(self, freq, orig_response):

    print_strings = [(pstr % (self._rnd,)) for pstr in self.PRINT_STRINGS]
    mutants = create_mutants(freq, print_strings, orig_resp=orig_response)
    self._send_mutants_in_threads(self._uri_opener.send_mutant, mutants, self._analyze_echo)
