diff --git a/conftest.py b/conftest.py
index fb67017d..e209b26d 100644
--- a/conftest.py
+++ b/conftest.py
@@ -6,7 +6,7 @@ from django.utils.translation import activate
 @pytest.fixture(scope="session")
 def django_db_setup(django_db_setup, django_db_blocker):
     with django_db_blocker.unblock():
-        call_command("setup")
+        call_command("populate")
 
 
 @pytest.fixture(scope="session", autouse=True)
diff --git a/core/management/commands/populate.py b/core/management/commands/populate.py
index a9285653..d42d9987 100644
--- a/core/management/commands/populate.py
+++ b/core/management/commands/populate.py
@@ -1098,8 +1098,10 @@ Welcome to the wiki page!
             n = News(
                 title="Repas barman",
                 summary="Enjoy la fin du semestre!",
-                content="Viens donc t'enjailler avec les autres barmans aux "
-                "frais du BdF! \o/",
+                content=(
+                    "Viens donc t'enjailler avec les autres barmans aux "
+                    "frais du BdF! \\o/"
+                ),
                 type="EVENT",
                 club=bar_club,
                 author=subscriber,
diff --git a/counter/models.py b/counter/models.py
index 29dfb92d..44818da5 100644
--- a/counter/models.py
+++ b/counter/models.py
@@ -19,7 +19,8 @@ import base64
 import os
 import random
 import string
-from datetime import date, datetime, timedelta, timezone
+from datetime import date, datetime, timedelta
+from datetime import timezone as tz
 from typing import Tuple
 
 from dict2xml import dict2xml
@@ -549,7 +550,7 @@ class Counter(models.Model):
         if since is None:
             since = get_start_of_semester()
         if isinstance(since, date):
-            since = datetime(since.year, since.month, since.day, tzinfo=timezone.utc)
+            since = datetime(since.year, since.month, since.day, tzinfo=tz.utc)
         return (
             self.sellings.filter(date__gte=since)
             .annotate(
@@ -583,7 +584,7 @@ class Counter(models.Model):
         if since is None:
             since = get_start_of_semester()
         if isinstance(since, date):
-            since = datetime(since.year, since.month, since.day, tzinfo=timezone.utc)
+            since = datetime(since.year, since.month, since.day, tzinfo=tz.utc)
         total = self.sellings.filter(date__gte=since).aggregate(
             total=Sum(F("quantity") * F("unit_price"), output_field=CurrencyField())
         )["total"]
diff --git a/doc/start/install.rst b/doc/start/install.rst
index fdb639ce..257fcf46 100644
--- a/doc/start/install.rst
+++ b/doc/start/install.rst
@@ -207,6 +207,29 @@ Pour lancer les tests il suffit d'utiliser la commande intégrée à django.
     # Lancer une méthode en particulier de cette même classe
     pytest core.tests.UserRegistrationTest.test_register_user_form_ok
 
+.. note::
+
+    Certains tests sont un peu longs à tourner.
+    Pour ne faire tourner que les tests les plus rapides,
+    vous pouvez exécutez pytest ainsi :
+
+    .. code-block:: bash
+
+        pytest -m "not slow"
+
+        # vous pouvez toujours faire comme au-dessus
+        pytest core -m "not slow"
+
+    A l'inverse, vous pouvez ne faire tourner que les tests
+    lents en remplaçant `-m "not slow"` par `-m slow`.
+
+    De cette manière, votre processus de développement
+    devrait être un peu plus fluide.
+    Cependant, n'oubliez pas de bien faire tourner
+    tous les tests avant de push un commit.
+
+
+
 Vérifier les dépendances Javascript
 -----------------------------------
 
diff --git a/eboutic/tests.py b/eboutic/tests.py
index b5e82e8e..b1ea9873 100644
--- a/eboutic/tests.py
+++ b/eboutic/tests.py
@@ -220,10 +220,11 @@ class EbouticTest(TestCase):
         self.client.get(reverse("eboutic:command"))
         response = self.client.get(et_answer_url)
         assert response.status_code == 500
-        assert (
-            "Basket processing failed with error: SuspiciousOperation('Basket total and amount do not match'"
-            in response.content.decode("utf-8"),
+        msg = (
+            "Basket processing failed with error: "
+            "SuspiciousOperation('Basket total and amount do not match'"
         )
+        assert msg in response.content.decode("utf-8")
 
     def test_buy_simple_product_with_credit_card(self):
         self.client.force_login(self.subscriber)
diff --git a/galaxy/management/commands/generate_galaxy_test_data.py b/galaxy/management/commands/generate_galaxy_test_data.py
index 191198f7..a1ff05a1 100644
--- a/galaxy/management/commands/generate_galaxy_test_data.py
+++ b/galaxy/management/commands/generate_galaxy_test_data.py
@@ -147,20 +147,20 @@ class Command(BaseCommand):
             self.logger.info(f"Creating {u}")
             self.users.append(u)
         User.objects.bulk_create(self.users)
-        self.users = User.objects.filter(username__startswith="galaxy-").all()
+        self.users = list(User.objects.filter(username__startswith="galaxy-").all())
 
         # now that users are created, create their subscription
         subs = []
-        for i in range(self.NB_USERS):
-            u = self.users[i]
-            self.logger.info(f"Registering {u}")
+        end = Subscription.compute_end(duration=2)
+        for i, user in enumerate(self.users):
+            self.logger.info(f"Registering {user}")
             subs.append(
                 Subscription(
-                    member=u,
+                    member=user,
                     subscription_start=Subscription.compute_start(
                         self.now - timedelta(days=self.NB_USERS - i)
                     ),
-                    subscription_end=Subscription.compute_end(duration=2),
+                    subscription_end=end,
                 )
             )
         Subscription.objects.bulk_create(subs)
@@ -381,28 +381,15 @@ class Command(BaseCommand):
         u1.godchildren.add(u3)
         self.logger.info(f"{u1} will be important and close to {u2} and {u3}")
         pictures_tags = []
-        for p in range(  # Mix them with other citizen for more chaos
-            uid - 400, uid - 200
-        ):
-            # users may already be on the pictures
-            if not self.picts[p].people.filter(user=u1).exists():
-                pictures_tags.append(
-                    PeoplePictureRelation(user=u1, picture=self.picts[p])
-                )
-            if not self.picts[p].people.filter(user=u2).exists():
-                pictures_tags.append(
-                    PeoplePictureRelation(user=u2, picture=self.picts[p])
-                )
-            if not self.picts[p + self.NB_USERS].people.filter(user=u1).exists():
-                pictures_tags.append(
-                    PeoplePictureRelation(
-                        user=u1, picture=self.picts[p + self.NB_USERS]
-                    )
-                )
-            if not self.picts[p + self.NB_USERS].people.filter(user=u2).exists():
-                pictures_tags.append(
-                    PeoplePictureRelation(
-                        user=u2, picture=self.picts[p + self.NB_USERS]
-                    )
-                )
-        PeoplePictureRelation.objects.bulk_create(pictures_tags)
+        for p in range(uid - 400, uid - 200):
+            # Mix them with other citizen for more chaos
+            pictures_tags += [
+                PeoplePictureRelation(user=u1, picture=self.picts[p]),
+                PeoplePictureRelation(user=u2, picture=self.picts[p]),
+                PeoplePictureRelation(user=u1, picture=self.picts[p + self.NB_USERS]),
+                PeoplePictureRelation(user=u2, picture=self.picts[p + self.NB_USERS]),
+            ]
+        # users may already be on the pictures.
+        # In this case the conflict will just be ignored
+        # and nothing will happen for this entry
+        PeoplePictureRelation.objects.bulk_create(pictures_tags, ignore_conflicts=True)
diff --git a/galaxy/tests.py b/galaxy/tests.py
index f1a3f092..cfbaf5ca 100644
--- a/galaxy/tests.py
+++ b/galaxy/tests.py
@@ -25,6 +25,7 @@
 import json
 from pathlib import Path
 
+import pytest
 from django.core.management import call_command
 from django.test import TestCase
 from django.urls import reverse
@@ -147,6 +148,7 @@ class GalaxyTestModel(TestCase):
             galaxy.rule(0)  # We want everybody here
 
 
+@pytest.mark.slow
 class GalaxyTestView(TestCase):
     @classmethod
     def setUpTestData(cls):
@@ -196,6 +198,4 @@ class GalaxyTestView(TestCase):
         # Dump computed state, either for easier debugging, or to copy as new reference if changes are legit
         (galaxy_dir / "test_galaxy_state.json").write_text(json.dumps(state))
 
-        assert (
-            state == json.loads((galaxy_dir / "ref_galaxy_state.json").read_text()),
-        )
+        assert state == json.loads((galaxy_dir / "ref_galaxy_state.json").read_text())
diff --git a/poetry.lock b/poetry.lock
index 06085a2a..318a5623 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -573,17 +573,17 @@ test = ["testfixtures"]
 
 [[package]]
 name = "djangorestframework"
-version = "3.15.1"
+version = "3.15.2"
 description = "Web APIs for Django, made easy."
 optional = false
-python-versions = ">=3.6"
+python-versions = ">=3.8"
 files = [
-    {file = "djangorestframework-3.15.1-py3-none-any.whl", hash = "sha256:3ccc0475bce968608cf30d07fb17d8e52d1d7fc8bfe779c905463200750cbca6"},
-    {file = "djangorestframework-3.15.1.tar.gz", hash = "sha256:f88fad74183dfc7144b2756d0d2ac716ea5b4c7c9840995ac3bfd8ec034333c1"},
+    {file = "djangorestframework-3.15.2-py3-none-any.whl", hash = "sha256:2b8871b062ba1aefc2de01f773875441a961fefbf79f5eed1e32b2f096944b20"},
+    {file = "djangorestframework-3.15.2.tar.gz", hash = "sha256:36fe88cd2d6c6bec23dca9804bab2ba5517a8bb9d8f47ebc68981b56840107ad"},
 ]
 
 [package.dependencies]
-django = ">=3.0"
+django = ">=4.2"
 
 [[package]]
 name = "docutils"
diff --git a/pyproject.toml b/pyproject.toml
index a2b9fe90..02d916ac 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -76,6 +76,7 @@ select = ["I", "F401"]
 [tool.pytest.ini_options]
 DJANGO_SETTINGS_MODULE = "sith.settings"
 python_files = ["tests.py", "test_*.py", "*_tests.py"]
+markers = ["slow"]
 
 [build-system]
 requires = ["poetry-core>=1.0.0"]
diff --git a/rootplace/tests.py b/rootplace/tests.py
index 81d0b616..5b9e2af1 100644
--- a/rootplace/tests.py
+++ b/rootplace/tests.py
@@ -72,7 +72,7 @@ class MergeUserTest(TestCase):
         assert "B'ian" == self.to_keep.nick_name
         assert "Jerusalem" == self.to_keep.address
         assert "Rome" == self.to_keep.parent_address
-        assert (3, self.to_keep.groups.count())
+        assert self.to_keep.groups.count() == 3
         groups = sorted(self.to_keep.groups.all(), key=lambda i: i.id)
         expected = sorted([subscribers, mde_admin, sas_admin], key=lambda i: i.id)
         assert groups == expected
diff --git a/sith/settings.py b/sith/settings.py
index 0489a8b1..b8d0541d 100644
--- a/sith/settings.py
+++ b/sith/settings.py
@@ -696,6 +696,17 @@ if DEBUG:
 
 if TESTING:
     CAPTCHA_TEST_MODE = True
+    PASSWORD_HASHERS = [  # not secure, but faster password hasher
+        "django.contrib.auth.hashers.MD5PasswordHasher",
+    ]
+    STORAGES = {  # store files in memory rather than using the hard drive
+        "default": {
+            "BACKEND": "django.core.files.storage.InMemoryStorage",
+        },
+        "staticfiles": {
+            "BACKEND": "django.contrib.staticfiles.storage.StaticFilesStorage",
+        },
+    }
 
 if SENTRY_DSN:
     # Connection to sentry