Add test for custom authentication backends and fix a little bit

aleksis/core/apps.py

@@ -2,6 +2,7 @@ from typing import Any, List, Optional, Tuple
 
 import django.apps
 from django.conf import settings
+from django.db import ProgrammingError
 from django.http import HttpRequest
 from django.utils.module_loading import autodiscover_modules
 
@@ -51,15 +52,23 @@ class CoreConfig(AppConfig):
 
         self._refresh_authentication_backends()
 
-    def _refresh_authentication_backends(self):
+    @classmethod
+    def _refresh_authentication_backends(cls):
         """Refresh config list of enabled authentication backends."""
         from .preferences import AuthenticationBackends  # noqa
 
         idx = settings.AUTHENTICATION_BACKENDS.index("django.contrib.auth.backends.ModelBackend")
 
-        for backend in get_site_preferences()["auth__backends"]:
-            settings._wrapped.AUTHENTICATION_BACKENDS.insert(idx, backend)
-            idx += 1
+        try:
+            # Don't set array directly in order to keep object reference
+            settings._wrapped.AUTHENTICATION_BACKENDS.clear()
+            settings._wrapped.AUTHENTICATION_BACKENDS += settings.ORIGINAL_AUTHENTICATION_BACKENDS
+
+            for backend in get_site_preferences()["auth__backends"]:
+                settings._wrapped.AUTHENTICATION_BACKENDS.insert(idx, backend)
+                idx += 1
+        except ProgrammingError:
+            pass
 
     def preference_updated(
         self,

aleksis/core/preferences.py

@@ -191,5 +191,7 @@ class AuthenticationBackends(MultipleChoicePreference):
     section = auth
     name = "backends"
     default = None
-    choices = [(b, b) for b in settings.CUSTOM_AUTHENTICATION_BACKENDS]
     verbose_name = _("Enabled custom authentication backends")
+
+    def get_choices(self):
+        return [(b, b) for b in settings.CUSTOM_AUTHENTICATION_BACKENDS]

aleksis/core/settings.py

@@ -690,3 +690,5 @@ HEALTH_CHECK = {
     "DISK_USAGE_MAX": _settings.get("health.disk_usage_max_percent", 90),
     "MEMORY_MIN": _settings.get("health.memory_min_mb", 500),
 }
+
+ORIGINAL_AUTHENTICATION_BACKENDS = AUTHENTICATION_BACKENDS[:]

aleksis/core/tests/test_authentication_backends.py

+from typing import Optional
+
+from django.contrib.auth import authenticate
+from django.contrib.auth.backends import BaseBackend
+from django.contrib.auth.base_user import AbstractBaseUser
+from django.contrib.auth.models import User
+
+import pytest
+
+from aleksis.core.apps import CoreConfig
+from aleksis.core.util.core_helpers import get_site_preferences
+
+pytestmark = pytest.mark.django_db
+
+
+class DummyBackend(BaseBackend):
+    def authenticate(
+        self, request, username: str, password: str, **kwargs
+    ) -> Optional[AbstractBaseUser]:
+        if username == "foo" and password == "baz":
+            return User.objects.get_or_create(username="foo")[0]
+
+
+backend_name = "aleksis.core.tests.test_authentication_backends.DummyBackend"
+
+
+def test_backends_simple(settings):
+
+    assert not authenticate(username="foo", password="baz")
+
+    assert backend_name not in settings.AUTHENTICATION_BACKENDS
+
+    settings.AUTHENTICATION_BACKENDS.append(backend_name)
+    assert backend_name in settings.AUTHENTICATION_BACKENDS
+
+    assert authenticate(username="foo", password="baz")
+
+    settings.AUTHENTICATION_BACKENDS.remove(backend_name)
+
+    assert not authenticate(username="foo", password="baz")
+
+
+def test_backends_with_activation(settings):
+    assert not authenticate(username="foo", password="baz")
+
+    settings.CUSTOM_AUTHENTICATION_BACKENDS.append(backend_name)
+
+    assert backend_name not in get_site_preferences()["auth__backends"]
+    assert backend_name not in settings.AUTHENTICATION_BACKENDS
+    assert not authenticate(username="foo", password="baz")
+
+    print(get_site_preferences()["auth__backends"])
+    print(get_site_preferences()["auth__backends"].append(backend_name))
+
+    get_site_preferences()["auth__backends"] = [backend_name]
+
+    assert backend_name in get_site_preferences()["auth__backends"]
+    assert backend_name in settings.AUTHENTICATION_BACKENDS
+    assert authenticate(username="foo", password="baz")
+
+    get_site_preferences()["auth__backends"] = []
+
+    assert backend_name not in get_site_preferences()["auth__backends"]
+    assert backend_name not in settings.AUTHENTICATION_BACKENDS