python3: auth_oidc mocked endpoint jwt encoding

tests/test_auth_oidc.py

@@ -32,6 +32,7 @@ from httmock import urlmatch, HTTMock
 from django.utils.timezone import utc
 from django.core.urlresolvers import reverse
 from django.contrib.auth import get_user_model
+from django.utils.encoding import force_text
 from django.utils.timezone import now
 from django.utils.six.moves.urllib import parse as urlparse
 
@@ -234,7 +235,7 @@ def oidc_provider_mock(oidc_provider, oidc_provider_jwkset, code, extra_id_token
                 k = base64url_encode(oidc_provider.client_secret.encode('utf-8'))
                 jwt.make_signed_token(
                     JWK(kty='oct',
-                        k=k.decode('ascii')))
+                        k=force_text(k)))
 
             content = {
                 'access_token': '1234',