update test to better version, also py3.13 compat

tests/test_examples.py

@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: Apache-2.0
 """Tests of example Python scripts."""
 import os
+import runpy
 from pathlib import Path
 
 
@@ -9,11 +10,7 @@ def test_load_example() -> None:
     cwd = Path.cwd()
     parent = Path(__file__).resolve().parent
     os.chdir(parent.parent)
-    exec(
-        open(parent / "load_cwl_by_path.py").read(),
-        globals(),
-        locals(),
-    )
+    result_raw = runpy.run_path(str(parent / "load_cwl_by_path.py"))
     os.chdir(cwd)
-    result = locals()["saved_obj"]
+    result = result_raw["saved_obj"]
     assert result["class"] == "Workflow"