from django.core.exceptions import PermissionDenied

from django.template.response import TemplateResponse

from django.test import SimpleTestCase, modify_settings, override_settings

from django.urls import path

class MiddlewareAccessingContent:

    def __init__(self, get_response):

        self.get_response = get_response

    def __call__(self, request):

        response = self.get_response(request)

        # Response.content should be available in the middleware even with a

        # TemplateResponse-based exception response.

        assert response.content

        return response

def template_response_error_handler(request, exception=None):

    return TemplateResponse(request, "test_handler.html", status=403)

def permission_denied_view(request):

    raise PermissionDenied

urlpatterns = [

    path("", permission_denied_view),

]

handler403 = template_response_error_handler

@override_settings(ROOT_URLCONF="handlers.tests_custom_error_handlers")

@modify_settings(

    MIDDLEWARE={

        "append": "handlers.tests_custom_error_handlers.MiddlewareAccessingContent"

    }

)

class CustomErrorHandlerTests(SimpleTestCase):

    def test_handler_renders_template_response(self):

        """

        BaseHandler should render TemplateResponse if necessary.

        """

        response = self.client.get("/")

        self.assertContains(response, "Error handler content", status_code=403)