def testGETXSSDriver(url: str, cookies: Mapping[str, str], driver: webdriver) -> Optional[str]:
""" If the given URL pops an alert box when accessed with the given cookies, return the contents of the alert box,
otherwise return None """
driver.setCookies(url, cookies)
try:
driver.get(url)
WebDriverWait(driver, config.timeout).until(expected_conditions.alert_is_present())
# Note that despite the name switch_to_alert also handles prompt:
# - http://selenium-python.readthedocs.io/navigating.html#popup-dialogs
alert = driver.switch_to_alert()
text = alert.text
driver.reset()
return text
except (TimeoutException, URLError):
driver.reset()
return None
