Derive AST import-helper boundary inventory from canonical guard list

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

Author: cursoragent

tests/test_ast_import_helper_import_boundary.py

@@ -3,13 +3,9 @@
 
 import pytest
 
-pytestmark = pytest.mark.architecture
-
+from tests.test_ast_import_helper_usage import AST_IMPORT_GUARD_MODULES
 
-EXPECTED_AST_IMPORT_HELPER_IMPORTERS = (
-    "tests/test_ast_function_source_helper_usage.py",
-    "tests/test_ast_function_source_import_boundary.py",
-)
+pytestmark = pytest.mark.architecture
 
 
 def _imports_ast_import_helper(module_text: str) -> bool:
@@ -32,4 +28,4 @@ def test_ast_import_helper_imports_are_centralized():
             continue
         discovered_modules.append(module_path.as_posix())
 
-    assert discovered_modules == list(EXPECTED_AST_IMPORT_HELPER_IMPORTERS)
+    assert discovered_modules == sorted(AST_IMPORT_GUARD_MODULES)