Fixed #22772 -- Defer wizard temporary files deletion.

import os

import tempfile

from django.http import HttpRequest

from django.http import HttpRequest, HttpResponse

from django.conf import settings

from django.contrib.auth.models import User

from django.core.files.storage import FileSystemStorage

        self.assertTrue(storage.file_storage.exists(tmp_name))

        storage.reset()

        storage.update_response(HttpResponse())

        self.assertFalse(storage.file_storage.exists(tmp_name))

        self.request = request

        self.file_storage = file_storage

        self._files = {}

        self._tmp_files = []

    def init_data(self):

        self.data = {

        }

    def reset(self):

        # Delete temporary files before breaking reference to them.

        # Store unused temporary file names in order to delete them

        # at the end of the response cycle through a callback attached in

        # `update_response`.

        wizard_files = self.data[self.step_files_key]

        for step_files in six.itervalues(wizard_files):

            for step_file in six.itervalues(step_files):

                self.file_storage.delete(step_file['tmp_name'])

                self._tmp_files.append(step_file['tmp_name'])

        self.init_data()

    def _get_current_step(self):

            for file in self._files.values():

                if not file.closed:

                    file.close()

            for tmp_file in self._tmp_files:

                self.file_storage.delete(tmp_file)

        if hasattr(response, 'render'):

            response.add_post_render_callback(post_render_callback)