✨(backend) serialize user language and timezone for frontend use

Add user language and timezone to serialized user data to enable frontend
customization. Allows backend email notifications to respect user's
localization preferences for improved communication relevance.

src/backend/core/api/serializers.py

@@ -4,6 +4,7 @@ from django.utils.translation import gettext_lazy as _
 
 from rest_framework import serializers
 from rest_framework.exceptions import PermissionDenied
+from timezone_field.rest_framework import TimeZoneSerializerField
 
 from core import models, utils
 
@@ -11,9 +12,11 @@ from core import models, utils
 class UserSerializer(serializers.ModelSerializer):
     """Serialize users."""
 
+    timezone = TimeZoneSerializerField()
+
     class Meta:
         model = models.User
-        fields = ["id", "email", "full_name", "short_name"]
+        fields = ["id", "email", "full_name", "short_name", "timezone", "language"]
         read_only_fields = ["id", "email", "full_name", "short_name"]
 
 

src/backend/core/tests/rooms/test_api_rooms_retrieve.py

@@ -336,10 +336,11 @@ def test_api_rooms_retrieve_authenticated():
         "url": "test_url_value",
     }
 )
-def test_api_rooms_retrieve_members(mock_token, django_assert_num_queries):
+def test_api_rooms_retrieve_members(mock_token, django_assert_num_queries, settings):
     """
     Users who are members of a room should be allowed to see related users.
     """
+    settings.TIME_ZONE = "UTC"
     user = UserFactory()
     other_user = UserFactory()
 
@@ -369,6 +370,8 @@ def test_api_rooms_retrieve_members(mock_token, django_assert_num_queries):
                     "email": user_access.user.email,
                     "full_name": user_access.user.full_name,
                     "short_name": user_access.user.short_name,
+                    "timezone": "UTC",
+                    "language": user_access.user.language,
                 },
                 "resource": str(room.id),
                 "role": user_access.role,
@@ -380,6 +383,8 @@ def test_api_rooms_retrieve_members(mock_token, django_assert_num_queries):
                     "email": other_user_access.user.email,
                     "full_name": other_user_access.user.full_name,
                     "short_name": other_user_access.user.short_name,
+                    "timezone": "UTC",
+                    "language": other_user_access.user.language,
                 },
                 "resource": str(room.id),
                 "role": other_user_access.role,
@@ -415,11 +420,14 @@ def test_api_rooms_retrieve_members(mock_token, django_assert_num_queries):
         "url": "test_url_value",
     }
 )
-def test_api_rooms_retrieve_administrators(mock_token, django_assert_num_queries):
+def test_api_rooms_retrieve_administrators(
+    mock_token, django_assert_num_queries, settings
+):
     """
     A user who is an administrator or owner of a room should be allowed
     to see related users.
     """
+    settings.TIME_ZONE = "UTC"
     user = UserFactory()
     other_user = UserFactory()
     room = RoomFactory()
@@ -448,6 +456,8 @@ def test_api_rooms_retrieve_administrators(mock_token, django_assert_num_queries
                     "email": other_user_access.user.email,
                     "full_name": other_user_access.user.full_name,
                     "short_name": other_user_access.user.short_name,
+                    "timezone": "UTC",
+                    "language": other_user_access.user.language,
                 },
                 "resource": str(room.id),
                 "role": other_user_access.role,
@@ -459,6 +469,8 @@ def test_api_rooms_retrieve_administrators(mock_token, django_assert_num_queries
                     "email": user_access.user.email,
                     "full_name": user_access.user.full_name,
                     "short_name": user_access.user.short_name,
+                    "timezone": "UTC",
+                    "language": user_access.user.language,
                 },
                 "resource": str(room.id),
                 "role": user_access.role,

src/backend/core/tests/test_api_users.py

@@ -103,8 +103,10 @@ def test_api_users_retrieve_me_anonymous():
     }
 
 
-def test_api_users_retrieve_me_authenticated():
+def test_api_users_retrieve_me_authenticated(settings):
     """Authenticated users should be able to retrieve their own user via the "/users/me" path."""
+
+    settings.TIME_ZONE = "UTC"
     user = factories.UserFactory()
 
     client = APIClient()
@@ -121,6 +123,8 @@ def test_api_users_retrieve_me_authenticated():
         "email": user.email,
         "full_name": user.full_name,
         "short_name": user.short_name,
+        "language": user.language,
+        "timezone": "UTC",
     }