✅(backend) fix test suites relying on boto3

In a5b2c2d0bc, we mocked `socket.getaddrinfo`
module but this one is also used by boto3 under the hood, so the mock brokes
all tests using boto3.

src/backend/core/tests/api/test_messages_import.py

@@ -2,7 +2,6 @@
 # pylint: disable=redefined-outer-name, unused-argument, no-value-for-parameter, too-many-lines
 
 import datetime
-import socket
 from unittest.mock import patch
 
 from django.core.files.storage import storages
@@ -27,14 +26,14 @@ def _mock_ssrf_dns():
 
     The IMAP endpoint validates the server hostname via
     ``core.services.ssrf.validate_hostname``; tests use unresolvable fixtures
-    like ``imap.example.com`` so we return a public IP to reach the mocked
-    IMAP task code.
+    like ``imap.example.com`` so we bypass validation to reach the mocked IMAP
+    task code. We patch the symbol imported into
+    ``core.services.importer.imap`` rather than ``socket.getaddrinfo``, which
+    would also break real DNS lookups (e.g. boto3 reaching the S3 bucket).
     """
     with patch(
-        "core.services.ssrf.socket.getaddrinfo",
-        return_value=[
-            (socket.AF_INET, socket.SOCK_STREAM, 6, "", ("93.184.216.34", 0))
-        ],
+        "core.services.importer.imap.validate_hostname",
+        return_value=["93.184.216.34"],
     ):
         yield
 

src/backend/core/tests/importer/conftest.py

@@ -1,6 +1,5 @@
 """Shared fixtures for importer tests."""
 
-import socket
 from unittest import mock
 
 import pytest
@@ -11,14 +10,14 @@ def _mock_ssrf_dns():
     """Short-circuit SSRF DNS validation for IMAP tests.
 
     The IMAP import path validates the server hostname via
-    ``core.services.ssrf.validate_hostname`` which calls ``socket.getaddrinfo``.
-    Test fixtures use unresolvable hostnames like ``imap.example.com``, so we
-    return a valid public IP here to let tests reach the mocked IMAP code.
+    ``core.services.ssrf.validate_hostname``. Test fixtures use unresolvable
+    hostnames like ``imap.example.com``, so we bypass validation here to let
+    tests reach the mocked IMAP code. We patch the symbol imported into
+    ``core.services.importer.imap`` rather than ``socket.getaddrinfo``, which
+    would also break real DNS lookups (e.g. boto3 reaching the S3 bucket).
     """
     with mock.patch(
-        "core.services.ssrf.socket.getaddrinfo",
-        return_value=[
-            (socket.AF_INET, socket.SOCK_STREAM, 6, "", ("93.184.216.34", 0))
-        ],
+        "core.services.importer.imap.validate_hostname",
+        return_value=["93.184.216.34"],
     ):
         yield

src/backend/messages/settings.py

@@ -1239,6 +1239,8 @@ class Test(Base):
     # Add a test encryption key for django-fernet-encrypted-fields
     SALT_KEY = ["test-salt-for-development-only"]
 
+    FEATURE_MAILBOX_ADMIN_CHANNELS = ["api_key", "widget"]
+
     SCHEMA_CUSTOM_ATTRIBUTES_USER = {}
     SCHEMA_CUSTOM_ATTRIBUTES_MAILDOMAIN = {}