Fix: fix some API crashes (#10196)

src/documents/tests/test_api_uisettings.py

@@ -117,6 +117,30 @@ class TestApiUiSettings(DirectoriesMixin, APITestCase):
 
         self.assertEqual(response.status_code, status.HTTP_200_OK)
 
+    def test_settings_must_be_dict(self):
+        """
+        GIVEN:
+            - API request to update ui_settings with settings not being a dict
+        WHEN:
+            - API is called
+        THEN:
+            - Correct HTTP 400 response
+        """
+        response = self.client.post(
+            self.ENDPOINT,
+            json.dumps(
+                {
+                    "settings": "not a dict",
+                },
+            ),
+            content_type="application/json",
+        )
+        self.assertEqual(response.status_code, status.HTTP_400_BAD_REQUEST)
+        self.assertIn(
+            "Expected a dictionary",
+            str(response.data["settings"]),
+        )
+
     @override_settings(
         OAUTH_CALLBACK_BASE_URL="http://localhost:8000",
         GMAIL_OAUTH_CLIENT_ID="abc123",