Merge pull request matplotlib#27109 from QuLogic/testing-importlib

TST: Use importlib for subprocess tests

Author: timhoffm

lib/matplotlib/testing/__init__.py

@@ -122,11 +122,16 @@ def subprocess_run_helper(func, *args, timeout, extra_env=None):
     """
     target = func.__name__
     module = func.__module__
+    file = func.__code__.co_filename
     proc = subprocess_run_for_testing(
         [
             sys.executable,
             "-c",
-            f"from {module} import {target}; {target}()",
+            f"import importlib.util;"
+            f"_spec = importlib.util.spec_from_file_location({module!r}, {file!r});"
+            f"_module = importlib.util.module_from_spec(_spec);"
+            f"_spec.loader.exec_module(_module);"
+            f"_module.{target}()",
             *args
         ],
         env={**os.environ, "SOURCE_DATE_EPOCH": "0", **(extra_env or {})},