'Assert that `xss_content` is not present in the content of
`response`, and that its escaped version is present. Uses the
same `markupsafe.escape` function as Mako templates.
Args:
response (Response): The HTTP response
xss_content (str): The Javascript code to check for.
Returns:
None'

def assert_no_xss(self, response, xss_content):

    self.assertContains(response, escape(xss_content))
    self.assertNotContains(response, xss_content)
