fix: correct WorldQuant daily alpha date filters

backend/app/worldquant.py

@@ -350,9 +350,13 @@ class WqClient:
             # Daily intervals are [UTC midnight, next midnight). Submitted dates
             # use the actual submission time, independently of creation or stage.
             field = "dateCreated" if submission == "UNSUBMITTED" else "dateSubmitted"
-            params.update({f"{field}>=": date_from, f"{field}<": date_to, "order": field})
+            # BRAIN treats the query separator '=' as part of its comparison
+            # syntax: a '>=' key adds an extra '=' and makes the date invalid.
+            # Both bounds are inclusive upstream; exclude the next UTC midnight.
+            upper = (datetime.fromisoformat(date_to) - timedelta(microseconds=1)).isoformat()
+            params.update({f"{field}>": date_from, f"{field}<": upper, "order": field})
             if field == "dateCreated":
-                params["dateCreated<"] = min(before, date_to)
+                params["dateCreated<"] = min(before, upper)
         return await self.get("/users/self/alphas", params)
 
     async def alpha(self, alpha_id):

backend/tests/browser_server.py

@@ -163,7 +163,9 @@ def create_test_app():
                 r for r in records if (r["status"] == "UNSUBMITTED") == unsubmitted and r["hidden"] == hidden
             ]
             for field in ("dateCreated", "dateSubmitted"):
-                for suffix in (">=", "<"):
+                if field + ">=" in request.url.params:
+                    return httpx.Response(400, json=["Expected ISO 8601 datetime with timezone"])
+                for suffix in (">", "<"):
                     boundary = request.url.params.get(field + suffix)
                     if boundary:
                         bound = datetime.fromisoformat(boundary).replace(tzinfo=timezone.utc)
@@ -173,8 +175,8 @@ def create_test_app():
                             if r.get(field)
                             and (
                                 datetime.fromisoformat(r[field]) >= bound
-                                if suffix == ">="
-                                else datetime.fromisoformat(r[field]) < bound
+                                if suffix == ">"
+                                else datetime.fromisoformat(r[field]) <= bound
                             )
                         ]
             offset, limit = (

backend/tests/test_alpha_management.py

@@ -318,12 +318,25 @@ async def test_scoped_date_query_parameters_and_no_platform_check(settings):
 
     def handler(request):
         requests.append(request)
-        return httpx.Response(200, json={"results": []})
+        # BRAIN parses the extra '=' as part of the datetime, returning HTTP 400.
+        if any(key.endswith(">=") for key in request.url.params):
+            return httpx.Response(400, json=["Expected ISO 8601 datetime with timezone"])
+        field = "dateCreated" if "status" in request.url.params else "dateSubmitted"
+        lower = datetime.fromisoformat(request.url.params[field + ">"])
+        upper = datetime.fromisoformat(request.url.params[field + "<"])
+        records = [
+            {"id": "midnight", field: "2025-01-01T00:00:00+00:00"},
+            {"id": "last", field: "2025-01-01T23:59:59.999999+00:00"},
+            {"id": "next", field: "2025-01-02T00:00:00+00:00"},
+        ]
+        return httpx.Response(200, json={"results": [
+            row for row in records if lower <= datetime.fromisoformat(row[field]) <= upper
+        ]})
 
     client = WqClient(settings, transport=httpx.MockTransport(handler))
     client.credentials, client.authenticated = ("test@example.com", "test"), True
     for submission in ("UNSUBMITTED", "SUBMITTED"):
-        await client.alphas(
+        result = await client.alphas(
             submission,
             True,
             100,
@@ -331,10 +344,11 @@ async def test_scoped_date_query_parameters_and_no_platform_check(settings):
             date_from="2025-01-01T00:00:00+00:00",
             date_to="2025-01-02T00:00:00+00:00",
         )
+        assert [row["id"] for row in result["results"]] == ["midnight", "last"]
     first, second = [dict(r.url.params) for r in requests]
-    assert first["dateCreated>="] == "2025-01-01T00:00:00+00:00"
-    assert first["dateCreated<"] == "2025-01-02T00:00:00+00:00"
-    assert second["dateSubmitted>="] == first["dateCreated>="]
+    assert first["dateCreated>"] == "2025-01-01T00:00:00+00:00"
+    assert first["dateCreated<"] == "2025-01-01T23:59:59.999999+00:00"
+    assert second["dateSubmitted>"] == first["dateCreated>"]
     assert second["dateSubmitted<"] == first["dateCreated<"]
     assert "status!" in second and second["hidden"] == "true"
     assert all(r.method == "GET" and r.url.path == "/users/self/alphas" for r in requests)