Log details obfuscated to not leak info

backend/tests/test_api.py

@@ -227,7 +227,31 @@ def test_admin_reports_smtp_validation_errors():
             'smtp_use_tls': False,
         })
     assert failed_validation.status_code == 503
-    assert 'connection refused' in failed_validation.json()['detail']
+    assert failed_validation.json()['detail'].startswith('SMTP validation failed. Reference: ')
+    assert 'connection refused' not in failed_validation.json()['detail']
+    assert failed_validation.headers['X-Request-ID']
+
+
+def test_request_id_is_preserved_and_sensitive_error_text_is_not_returned():
+    headers = login_headers()
+    with get_connection() as conn:
+        conn.execute('DELETE FROM app_settings WHERE name = ?', ('admin_smtp_mail_rate',))
+        conn.commit()
+    with patch('backend.app.api.admin.send_test_email', side_effect=RuntimeError('password=super-secret token=abc123')):
+        response = client.post(
+            '/api/admin/smtp/test',
+            headers={**headers, 'X-Request-ID': 'audit-test-123'},
+            json={
+                'smtp_host': 'smtp.example.com',
+                'smtp_port': 2525,
+                'smtp_from': 'admin@example.com',
+            },
+        )
+    assert response.status_code == 503
+    assert response.headers['X-Request-ID'] == 'audit-test-123'
+    assert response.json()['detail'] == 'SMTP validation failed. Reference: audit-test-123'
+    assert 'super-secret' not in response.text
+    assert 'abc123' not in response.text
 
 
 def test_admin_can_add_list_and_remove_users():