Allow object permissions with dots.

AUTHORS

@@ -58,3 +58,4 @@ Authors ordered by first contribution
 - Adam Dobrawy <guardian@jawnosc.tk>
 - Jeff Hackshaw <intrepidevio@gmail.com>
 - Chase Bennett <ch@se.gd>
+- Jonny Arnold <jonny.arnold89@gmail.com>

guardian/shortcuts.py

@@ -89,7 +89,8 @@ def assign_perm(perm, user_or_group, obj=None):
             return perm
 
     if not isinstance(perm, Permission):
-        perm = perm.split('.')[-1]
+        if '.' in perm:
+            app_label, perm = perm.split(".", 1)
 
     if isinstance(obj, QuerySet):
         if isinstance(user_or_group, (QuerySet, list)):

guardian/testapp/tests/test_shortcuts.py

@@ -118,6 +118,15 @@ def test_group_assign_perm_global(self):
         self.assertTrue(self.user.has_perm("contenttypes.change_contenttype"))
         self.assertTrue(isinstance(perm, Permission))
 
+    def test_assign_perm_with_dots(self):
+        Permission.objects.create(
+            codename="contenttype.reorder",
+            content_type=ContentType.objects.get_for_model(self.ctype)
+        )
+
+        assign_perm("contenttypes.contenttype.reorder", self.user, self.ctype)
+        self.assertTrue(self.user.has_perm("contenttypes.contenttype.reorder", self.ctype))
+
     def test_deprecation_warning(self):
         with warnings.catch_warnings(record=True) as warns:
             warnings.simplefilter('always')