fix: werkzeug query parameter serialization

Author: azmeuk

doc/changelog.rst

@@ -1,6 +1,13 @@
 Changelog
 =========
 
+[unreleased]
+------------
+
+Fixed
+^^^^^
+- Werkzeug engine now correctly serializes list query parameters (``attributes``, ``excludedAttributes``).
+
 [0.7.4] - 2026-04-02
 --------------------
 

scim2_client/engines/werkzeug.py

@@ -161,7 +161,7 @@ def query(
             **kwargs,
         )
 
-        query_string = urlencode(req.payload, doseq=False) if req.payload else None
+        query_string = urlencode(req.payload, doseq=True) if req.payload else None
         environ = {**self.environ, **req.request_kwargs}
         response = self.client.get(
             self._make_url(req.url), query_string=query_string, **environ

tests/engines/test_werkzeug.py

@@ -1,6 +1,7 @@
 import pytest
 from scim2_models import PatchOp
 from scim2_models import PatchOperation
+from scim2_models import ResponseParameters
 from scim2_models import SearchRequest
 from scim2_models import User
 from werkzeug.test import Client
@@ -77,6 +78,18 @@ def test_werkzeug_engine(scim_client):
         scim_client.query(User, response_user.id)
 
 
+def test_werkzeug_query_with_attributes(scim_client):
+    """List query parameters like attributes are correctly serialized in the query string."""
+    User = scim_client.get_resource_model("User")
+    request_user = User(user_name="foo", display_name="bar", title="Engineer")
+    response_user = scim_client.create(request_user)
+
+    params = ResponseParameters(attributes=["displayName"])
+    result = scim_client.query(User, response_user.id, query_parameters=params)
+    assert result.display_name == "bar"
+    assert result.title is None
+
+
 def test_no_json():
     """Test that pages that do not return JSON raise an UnexpectedContentFormat error."""