Fixed #19802 -- Fixed HttpResponse.set_cookie() with unicode data on Python 2.

Thanks django at patrickbregman.eu for the report.

django/http/response.py

@@ -13,7 +13,7 @@ from django.core.exceptions import DisallowedRedirect
 from django.core.serializers.json import DjangoJSONEncoder
 from django.http.cookie import SimpleCookie
 from django.utils import six, timezone
-from django.utils.encoding import force_bytes, force_text, iri_to_uri
+from django.utils.encoding import force_bytes, force_text, force_str, iri_to_uri
 from django.utils.http import cookie_date
 from django.utils.six.moves import map
 from django.utils.six.moves.urllib.parse import urlparse
@@ -221,6 +221,7 @@ class HttpResponseBase(six.Iterator):
         If it is a ``datetime.datetime`` object then ``max_age`` will be calculated.
 
         """
+        value = force_str(value)
         self.cookies[key] = value
         if expires is not None:
             if isinstance(expires, datetime.datetime):

tests/requests/tests.py

@@ -14,6 +14,7 @@ from django.test import SimpleTestCase, RequestFactory, override_settings
 from django.test.client import FakePayload
 from django.test.utils import str_prefix
 from django.utils import six
+from django.utils.encoding import force_str
 from django.utils.http import cookie_date, urlencode
 from django.utils.six.moves.urllib.parse import urlencode as original_urlencode
 from django.utils.timezone import utc
@@ -193,6 +194,13 @@ class RequestsTests(SimpleTestCase):
         self.assertTrue('; httponly' in str(example_cookie))
         self.assertTrue(example_cookie['httponly'])
 
+    def test_unicode_cookie(self):
+        "Verify HttpResponse.set_cookie() works with unicode data."
+        response = HttpResponse()
+        cookie_value = '清風'
+        response.set_cookie('test', cookie_value)
+        self.assertEqual(force_str(cookie_value), response.cookies['test'].value)
+
     def test_limited_stream(self):
         # Read all of a limited stream
         stream = LimitedStream(BytesIO(b'test'), 2)