from django.contrib.messages import constants

from django.contrib.messages.storage.base import Message

from django.contrib.messages.storage.session import SessionStorage

from django.core.exceptions import ImproperlyConfigured

from django.http import HttpRequest

from django.test import TestCase

from django.utils.safestring import SafeData, mark_safe

from .base import BaseTests

def set_session_data(storage, messages):

    """

    Sets the messages into the backend request's session and remove the

    backend's loaded data cache.

    """

    storage.request.session[storage.session_key] = storage.serialize_messages(messages)

    if hasattr(storage, "_loaded_data"):

        del storage._loaded_data

def stored_session_messages_count(storage):

    data = storage.deserialize_messages(

        storage.request.session.get(storage.session_key, [])

    )

    return len(data)

class SessionTests(BaseTests, TestCase):

    storage_class = SessionStorage

    def get_request(self):

        self.session = {}

        request = super().get_request()

        request.session = self.session

        return request

    def stored_messages_count(self, storage, response):

        return stored_session_messages_count(storage)

    def test_no_session(self):

        msg = (

            "The session-based temporary message storage requires session "

            "middleware to be installed, and come before the message "

            "middleware in the MIDDLEWARE list."

        )

        with self.assertRaisesMessage(ImproperlyConfigured, msg):

            self.storage_class(HttpRequest())

    def test_get(self):

        storage = self.storage_class(self.get_request())

        example_messages = ["test", "me"]

        set_session_data(storage, example_messages)

        self.assertEqual(list(storage), example_messages)

    def test_safedata(self):

        """

        A message containing SafeData keeps its safe status when retrieved from

        the message storage.

        """

        storage = self.get_storage()

        message = Message(constants.DEBUG, mark_safe("<b>Hello Django!</b>"))

        set_session_data(storage, [message])

        self.assertIsInstance(list(storage)[0].message, SafeData)