Cover AST function-source helper top-level extraction semantics

Co-authored-by: Shri Sukhani <shrisukhani@users.noreply.github.com>

Author: cursoragent

tests/test_ast_function_source_utils.py

@@ -21,3 +21,23 @@ def test_collect_function_sources_reads_sync_and_async_functions():
     assert "post_model_response_data_async(" in function_sources[
         "post_model_request_async"
     ]
+
+
+def test_collect_function_sources_returns_top_level_functions_only(tmp_path):
+    module_path = tmp_path / "sample_module.py"
+    module_path.write_text(
+        "def top_level():\n"
+        "    return 'ok'\n\n"
+        "class Example:\n"
+        "    def method(self):\n"
+        "        return 'method'\n\n"
+        "def wrapper():\n"
+        "    def nested():\n"
+        "        return 'nested'\n"
+        "    return nested()\n",
+        encoding="utf-8",
+    )
+
+    function_sources = collect_function_sources(str(module_path))
+
+    assert sorted(function_sources.keys()) == ["top_level", "wrapper"]