The user has provided valid credentials (this was checked in AuthenticationForm.is_valid()). So now we
        can check the test cookie stuff and log him in.

def form_valid(self, form):
        """
        The user has provided valid credentials (this was checked in AuthenticationForm.is_valid()). So now we
        can check the test cookie stuff and log him in.
        """
        self.check_and_delete_test_cookie()
        login(self.request, form.get_user())
        return super(LoginView, self).form_valid(form)