fix: fetch dataset scope options from WorldQuant platform

backend/tests/catalog_fake.py

@@ -21,6 +21,8 @@ def field_records(dataset="TEST_FIN", count=123):
 
 def catalog_response(request, fields=None):
     path, params = request.url.path, request.url.params
+    if request.method == "OPTIONS" and path == "/simulations":
+        return httpx.Response(200, json=platform_response())
     if path not in ("/data-sets", "/data-fields"):
         return None
     assert request.method == "GET"
@@ -53,3 +55,18 @@ def catalog_response(request, fields=None):
         rows = rows[:50] + [rows[49]] + rows[50:]
     offset, limit = int(params.get("offset", 0)), int(params.get("limit", 50))
     return httpx.Response(200, json={"results": rows[offset : offset + limit]})
+
+
+def platform_response():
+    """Synthetic upstream options include a previously unsupported market and delay."""
+    def values(items):
+        return [{"value": item} for item in items]
+    regions = {"USA": ["TOP3000", "TOP1000"], "CHN": ["TOP2000U"], "IND": ["TOP500"]}
+    children = {"instrumentType": {"choices": values(["EQUITY"])},
+                "region": {"choices": {"instrumentType": {"EQUITY": values(regions)}}}}
+    for key in ("universe", "delay"):
+        children[key] = {"choices": {"instrumentType": {"EQUITY": {"region": {
+            region: values(universes if key == "universe" else [0, 1] if region == "USA" else [1])
+            for region, universes in regions.items()
+        }}}}}
+    return {"actions": {"POST": {"settings": {"children": children}}}}