diff --git a/cachalot/admin_tests/__init__.py b/cachalot/admin_tests/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/cachalot/admin_tests/admin.py b/cachalot/admin_tests/admin.py
new file mode 100644
index 0000000..dc42133
--- /dev/null
+++ b/cachalot/admin_tests/admin.py
@@ -0,0 +1,6 @@
+from django.contrib import admin
+from .models import TestModel
+
+@admin.register(TestModel)
+class TestModelAdmin(admin.ModelAdmin):
+    list_display = ('name', 'owner')
diff --git a/cachalot/admin_tests/migrations/0001_initial.py b/cachalot/admin_tests/migrations/0001_initial.py
new file mode 100644
index 0000000..9e41fe6
--- /dev/null
+++ b/cachalot/admin_tests/migrations/0001_initial.py
@@ -0,0 +1,52 @@
+# Generated by Django 4.1.7 on 2023-03-10 19:33
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+import django.db.models.functions.text
+
+
+class Migration(migrations.Migration):
+    initial = True
+
+    dependencies = [
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name="TestModel",
+            fields=[
+                (
+                    "id",
+                    models.AutoField(
+                        auto_created=True,
+                        primary_key=True,
+                        serialize=False,
+                        verbose_name="ID",
+                    ),
+                ),
+                ("name", models.CharField(max_length=20)),
+                (
+                    "owner",
+                    models.ForeignKey(
+                        blank=True,
+                        null=True,
+                        on_delete=django.db.models.deletion.SET_NULL,
+                        to=settings.AUTH_USER_MODEL,
+                    ),
+                ),
+            ],
+            options={
+                "ordering": ("name",),
+            },
+        ),
+        migrations.AddConstraint(
+            model_name="testmodel",
+            constraint=models.UniqueConstraint(
+                fields=["name"],
+                condition=models.Q(owner=None),
+                name="unique_name",
+            ),
+        ),
+    ]
diff --git a/cachalot/admin_tests/migrations/__init__.py b/cachalot/admin_tests/migrations/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/cachalot/admin_tests/models.py b/cachalot/admin_tests/models.py
new file mode 100644
index 0000000..15ce4eb
--- /dev/null
+++ b/cachalot/admin_tests/models.py
@@ -0,0 +1,18 @@
+from django.conf import settings
+from django.db.models import Q, UniqueConstraint, Model, CharField, ForeignKey, SET_NULL
+
+
+class TestModel(Model):
+    name = CharField(max_length=20)
+    owner = ForeignKey(settings.AUTH_USER_MODEL, null=True, blank=True,
+                       on_delete=SET_NULL)
+
+    class Meta:
+        ordering = ('name',)
+        constraints = [
+            UniqueConstraint(
+                fields=["name"],
+                condition=Q(owner=None),
+                name="unique_name",
+            )
+        ]
diff --git a/cachalot/admin_tests/test_admin.py b/cachalot/admin_tests/test_admin.py
new file mode 100644
index 0000000..81df0fe
--- /dev/null
+++ b/cachalot/admin_tests/test_admin.py
@@ -0,0 +1,19 @@
+from django.test import TestCase
+from django.contrib.auth.models import User
+from .models import TestModel
+from django.test import Client
+
+
+class AdminTestCase(TestCase):
+    def setUp(self):
+        self.client = Client()
+        self.user = User.objects.create(username='admin', is_staff=True, is_superuser=True)
+
+    def test_save_test_model(self):
+        """
+        Model 'TestModel' has UniqueConstraint which caused problems when saving TestModelAdmin in Django >= 4.1
+        """
+        self.client.force_login(self.user)
+        response = self.client.post('/admin/admin_tests/testmodel/add/', {'name': 'test', 'public': True})
+        self.assertEqual(response.status_code, 302)
+        self.assertEqual(TestModel.objects.count(), 1)
diff --git a/cachalot/tests/read.py b/cachalot/tests/read.py
index a08237e..f06354a 100644
--- a/cachalot/tests/read.py
+++ b/cachalot/tests/read.py
@@ -52,12 +52,13 @@ class ReadTestCase(TestUtilsMixin, TransactionTestCase):
         self.group__permissions = list(Permission.objects.all()[:3])
         self.group.permissions.add(*self.group__permissions)
         self.user = User.objects.create_user('user')
-        self.user__permissions = list(Permission.objects.all()[3:6])
+        self.user__permissions = list(Permission.objects.filter(content_type__app_label='auth')[3:6])
         self.user.groups.add(self.group)
         self.user.user_permissions.add(*self.user__permissions)
         self.admin = User.objects.create_superuser('admin', 'admin@test.me',
                                                    'password')
-        self.t1__permission = (Permission.objects.order_by('?')
+        self.t1__permission = (Permission.objects
+                               .order_by('?')
                                .select_related('content_type')[0])
         self.t1 = Test.objects.create(
             name='test1', owner=self.user,
diff --git a/runtests.py b/runtests.py
index 14496e3..11f53a0 100755
--- a/runtests.py
+++ b/runtests.py
@@ -9,6 +9,6 @@ if __name__ == '__main__':
     django.setup()
     from django.test.runner import DiscoverRunner
     test_runner = DiscoverRunner(verbosity=2, interactive=False)
-    failures = test_runner.run_tests(['cachalot.tests'])
+    failures = test_runner.run_tests(['cachalot.tests', 'cachalot.admin_tests'])
     if failures:
         sys.exit(failures)
diff --git a/runtests_urls.py b/runtests_urls.py
index b11ff8c..4ca4fd1 100644
--- a/runtests_urls.py
+++ b/runtests_urls.py
@@ -1,6 +1,7 @@
 import debug_toolbar
-from django.urls import re_path, include
+from django.urls import path, re_path, include
 from django.http import HttpResponse
+from django.contrib import admin
 
 
 def empty_page(request):
@@ -10,4 +11,5 @@ def empty_page(request):
 urlpatterns = [
     re_path(r'^$', empty_page),
     re_path(r'^__debug__/', include(debug_toolbar.urls)),
+    path('admin/', admin.site.urls),
 ]
diff --git a/settings.py b/settings.py
index 0c1a89f..19d7560 100644
--- a/settings.py
+++ b/settings.py
@@ -12,6 +12,7 @@ DATABASES = {
         'ENGINE': 'django.db.backends.postgresql',
         'NAME': 'cachalot',
         'USER': 'cachalot',
+        'PASSWORD': 'password',
         'HOST': '127.0.0.1',
     },
     'mysql': {
@@ -90,9 +91,13 @@ elif DEFAULT_CACHE_ALIAS == 'pylibmc':
 
 INSTALLED_APPS = [
     'cachalot',
+    'cachalot.admin_tests',
     'django.contrib.auth',
     'django.contrib.contenttypes',
     'django.contrib.postgres',  # Enables the unaccent lookup.
+    'django.contrib.sessions',
+    'django.contrib.admin',
+    'django.contrib.messages',
 ]
 
 MIGRATION_MODULES = {
@@ -104,6 +109,12 @@ TEMPLATES = [
         'BACKEND': 'django.template.backends.django.DjangoTemplates',
         'DIRS': [],
         'APP_DIRS': True,
+        'OPTIONS': {
+            'context_processors': [
+                'django.contrib.auth.context_processors.auth',
+                'django.contrib.messages.context_processors.messages',
+            ],
+        }
     },
     {
         'BACKEND': 'django.template.backends.jinja2.Jinja2',
@@ -116,7 +127,11 @@ TEMPLATES = [
     }
 ]
 
-MIDDLEWARE = []
+MIDDLEWARE = [
+    'django.contrib.sessions.middleware.SessionMiddleware',
+    'django.contrib.auth.middleware.AuthenticationMiddleware',
+    'django.contrib.messages.middleware.MessageMiddleware',
+]
 PASSWORD_HASHERS = ['django.contrib.auth.hashers.MD5PasswordHasher']
 SECRET_KEY = 'it’s not important in tests but we have to set it'