Better usage of cache for groups and clubs related operations (#634)

* Better usage of cache for group retrieval

* Cache clearing on object deletion or update

* replace signals by save and delete override

* add is_anonymous check in is_owned_by

Add in many is_owned_by(self, user) methods that user is not anonymous. Since many of those functions do db queries, this should reduce a little bit the load of the db.

* Stricter usage of User.is_in_group

Constrain the parameters that can be passed to the function to make sure only a str or an int can be used. Also force to explicitly specify if the group id or the group name is used.

* write test and correct bugs

* remove forgotten populate commands

* Correct test

com/tests.py

@@ -13,16 +13,18 @@
 # OR WITHIN THE LOCAL FILE "LICENSE"
 #
 #
-
+from django.core.files.uploadedfile import SimpleUploadedFile
 from django.test import TestCase
 from django.conf import settings
 from django.urls import reverse
 from django.core.management import call_command
 from django.utils import html
+from django.utils.timezone import localtime, now
 from django.utils.translation import gettext as _
 
-
-from core.models import User, RealGroup
+from club.models import Club, Membership
+from com.models import Sith, News, Weekmail, WeekmailArticle, Poster
+from core.models import User, RealGroup, AnonymousUser
 
 
 class ComAlertTest(TestCase):
@@ -110,3 +112,102 @@ class ComTest(TestCase):
                 _("You need an up to date subscription to access this content")
             ),
         )
+
+
+class SithTest(TestCase):
+    def test_sith_owner(self):
+        """
+        Test that the sith instance is owned by com admins
+        and nobody else
+        """
+        sith: Sith = Sith.objects.first()
+
+        com_admin = User.objects.get(username="comunity")
+        self.assertTrue(sith.is_owned_by(com_admin))
+
+        anonymous = AnonymousUser()
+        self.assertFalse(sith.is_owned_by(anonymous))
+
+        sli = User.objects.get(username="sli")
+        self.assertFalse(sith.is_owned_by(sli))
+
+
+class NewsTest(TestCase):
+    @classmethod
+    def setUpTestData(cls):
+        cls.com_admin = User.objects.get(username="comunity")
+        new = News.objects.create(
+            title="dummy new",
+            summary="This is a dummy new",
+            content="Look at that beautiful dummy new",
+            author=User.objects.get(username="subscriber"),
+            club=Club.objects.first(),
+        )
+        cls.new = new
+        cls.author = new.author
+        cls.sli = User.objects.get(username="sli")
+        cls.anonymous = AnonymousUser()
+
+    def test_news_owner(self):
+        """
+        Test that news are owned by com admins
+        or by their author but nobody else
+        """
+
+        self.assertTrue(self.new.is_owned_by(self.com_admin))
+        self.assertTrue(self.new.is_owned_by(self.author))
+        self.assertFalse(self.new.is_owned_by(self.anonymous))
+        self.assertFalse(self.new.is_owned_by(self.sli))
+
+
+class WeekmailArticleTest(TestCase):
+    @classmethod
+    def setUpTestData(cls):
+        cls.com_admin = User.objects.get(username="comunity")
+        author = User.objects.get(username="subscriber")
+        cls.article = WeekmailArticle.objects.create(
+            weekmail=Weekmail.objects.create(),
+            author=author,
+            title="title",
+            content="Some content",
+            club=Club.objects.first(),
+        )
+        cls.author = author
+        cls.sli = User.objects.get(username="sli")
+        cls.anonymous = AnonymousUser()
+
+    def test_weekmail_owner(self):
+        """
+        Test that weekmails are owned only by com admins
+        """
+        self.assertTrue(self.article.is_owned_by(self.com_admin))
+        self.assertFalse(self.article.is_owned_by(self.author))
+        self.assertFalse(self.article.is_owned_by(self.anonymous))
+        self.assertFalse(self.article.is_owned_by(self.sli))
+
+
+class PosterTest(TestCase):
+    @classmethod
+    def setUpTestData(cls):
+        cls.com_admin = User.objects.get(username="comunity")
+        cls.poster = Poster.objects.create(
+            name="dummy",
+            file=SimpleUploadedFile("dummy.jpg", b"azertyuiop"),
+            club=Club.objects.first(),
+            date_begin=localtime(now()),
+        )
+        cls.sli = User.objects.get(username="sli")
+        cls.sli.memberships.all().delete()
+        Membership(user=cls.sli, club=Club.objects.first(), role=5).save()
+        cls.susbcriber = User.objects.get(username="subscriber")
+        cls.anonymous = AnonymousUser()
+
+    def test_poster_owner(self):
+        """
+        Test that poster are owned by com admins and board members in clubs
+        """
+        self.assertTrue(self.poster.is_owned_by(self.com_admin))
+        self.assertFalse(self.poster.is_owned_by(self.anonymous))
+
+        self.assertFalse(self.poster.is_owned_by(self.susbcriber))
+        self.assertTrue(self.poster.is_owned_by(self.sli))