Add regression tests for code_interpreter middleware PTC allowlist

- Ensure 'task' is excluded from the default PTC allowlist to prevent ValueError in langchain-quickjs >=0.3.
- Verify that essential async dispatch tools remain in the allowlist.
- Confirm that the live quickjs filter accepts the default allowlist even with a 'task' tool present.
- Test the creation of the code_interpreter middleware to ensure it builds correctly.

tests/test_code_interpreter_middleware.py

@@ -0,0 +1,47 @@
+"""Regression tests for the code_interpreter PTC allowlist.
+
+langchain-quickjs >=0.3 reserves the ``task`` sub-agent dispatch tool as the
+top-level REPL global and raises ``ValueError`` if ``task`` appears in the
+``ptc`` allowlist. EvoScientist must therefore keep ``task`` out of the
+allowlist (``task()`` stays reachable as the REPL global, with responseSchema).
+"""
+
+from __future__ import annotations
+
+import pytest
+
+from EvoScientist.middleware.code_interpreter import (
+    _DEFAULT_PTC_ALLOWLIST,
+    create_code_interpreter_middleware,
+)
+
+
+def test_task_excluded_from_ptc_allowlist():
+    # Exposing `task` via ptc raises on quickjs >=0.3 — it is the REPL global.
+    assert "task" not in _DEFAULT_PTC_ALLOWLIST
+
+
+def test_async_dispatch_tools_remain_in_allowlist():
+    # Guard against over-deletion: async fan-out is the killer PTC use case.
+    for name in ("start_async_task", "check_async_task", "list_async_tasks"):
+        assert name in _DEFAULT_PTC_ALLOWLIST
+
+
+def test_filter_tools_for_ptc_accepts_default_allowlist():
+    # End-to-end guard: the live quickjs filter must accept our allowlist even
+    # when a `task` tool is present in the agent toolset.
+    _ptc = pytest.importorskip("langchain_quickjs._ptc")
+    from langchain_core.tools import tool
+
+    @tool
+    def task(description: str) -> str:
+        """dummy sub-agent dispatch tool"""
+        return "ok"
+
+    _ptc.filter_tools_for_ptc(
+        [task], _DEFAULT_PTC_ALLOWLIST, self_tool_name="code_interpreter"
+    )
+
+
+def test_create_code_interpreter_middleware_builds():
+    assert create_code_interpreter_middleware() is not None