name : test_lazyloading.py import sys import importlib from importlib.util import LazyLoader, find_spec, module_from_spec import pytest # Warning raised by _reload_guard() in numpy/__init__.py @pytest.mark.filterwarnings("ignore:The NumPy module was reloaded") def test_lazy_load(): # gh-22045. lazyload doesn't import submodule names into the namespace # muck with sys.modules to test the importing system old_numpy = sys.modules.pop("numpy") numpy_modules = {} for mod_name, mod in list(sys.modules.items()): if mod_name[:6] == "numpy.": numpy_modules[mod_name] = mod sys.modules.pop(mod_name) try: # create lazy load of numpy as np spec = find_spec("numpy") module = module_from_spec(spec) sys.modules["numpy"] = module loader = LazyLoader(spec.loader) loader.exec_module(module) np = module # test a subpackage import from numpy.lib import recfunctions # test triggering the import of the package np.ndarray finally: if old_numpy: sys.modules["numpy"] = old_numpy sys.modules.update(numpy_modules)