Fix `test_importlib` under WASI SDK 21

[brettcannon]

Bug report

Bug description:

This very likely stems from dlopen() being available in WASI SDK 21 but not being usable dynamically as-is.

Test failure output

======================================================================
ERROR: test_is_package (test.test_importlib.extension.test_loader.Frozen_LoaderTests.test_is_package)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 86, in test_is_package
    self.assertFalse(self.loader.is_package(util.EXTENSIONS.name))
                     ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap_external>", line 1322, in is_package
  File "<frozen importlib._bootstrap_external>", line 134, in _path_split
  File "<frozen importlib._bootstrap_external>", line 134, in <genexpr>
AttributeError: 'NoneType' object has no attribute 'rfind'

======================================================================
ERROR: test_load_module_API (test.test_importlib.extension.test_loader.Frozen_LoaderTests.test_load_module_API)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 48, in test_load_module_API
    self.loader.load_module()
    ~~~~~~~~~~~~~~~~~~~~~~~^^
  File "<frozen importlib._bootstrap_external>", line 668, in _check_name_wrapper
  File "<frozen importlib._bootstrap_external>", line 1195, in load_module
  File "<frozen importlib._bootstrap_external>", line 1019, in load_module
  File "<frozen importlib._bootstrap>", line 531, in _load_module_shim
  File "<frozen importlib._bootstrap>", line 673, in spec_from_loader
  File "<frozen importlib._bootstrap_external>", line 875, in spec_from_file_location
  File "<frozen importlib._bootstrap_external>", line 1322, in is_package
  File "<frozen importlib._bootstrap_external>", line 134, in _path_split
  File "<frozen importlib._bootstrap_external>", line 134, in <genexpr>
AttributeError: 'NoneType' object has no attribute 'rfind'

======================================================================
ERROR: test_module (test.test_importlib.extension.test_loader.Frozen_LoaderTests.test_module)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 55, in test_module
    module = self.load_module(util.EXTENSIONS.name)
             ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^
  File "/Lib/test/test_importlib/extension/test_loader.py", line 32, in load_module
    return self.loader.load_module(fullname)
           ~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^
  File "<frozen importlib._bootstrap_external>", line 668, in _check_name_wrapper
  File "<frozen importlib._bootstrap_external>", line 1195, in load_module
  File "<frozen importlib._bootstrap_external>", line 1019, in load_module
  File "<frozen importlib._bootstrap>", line 531, in _load_module_shim
  File "<frozen importlib._bootstrap>", line 673, in spec_from_loader
  File "<frozen importlib._bootstrap_external>", line 875, in spec_from_file_location
  File "<frozen importlib._bootstrap_external>", line 1322, in is_package
  File "<frozen importlib._bootstrap_external>", line 134, in _path_split
  File "<frozen importlib._bootstrap_external>", line 134, in <genexpr>
AttributeError: 'NoneType' object has no attribute 'rfind'

======================================================================
ERROR: test_module_reuse (test.test_importlib.extension.test_loader.Frozen_LoaderTests.test_module_reuse)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 81, in test_module_reuse
    module1 = self.load_module(util.EXTENSIONS.name)
              ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^
  File "/Lib/test/test_importlib/extension/test_loader.py", line 32, in load_module
    return self.loader.load_module(fullname)
           ~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^
  File "<frozen importlib._bootstrap_external>", line 668, in _check_name_wrapper
  File "<frozen importlib._bootstrap_external>", line 1195, in load_module
  File "<frozen importlib._bootstrap_external>", line 1019, in load_module
  File "<frozen importlib._bootstrap>", line 531, in _load_module_shim
  File "<frozen importlib._bootstrap>", line 673, in spec_from_loader
  File "<frozen importlib._bootstrap_external>", line 875, in spec_from_file_location
  File "<frozen importlib._bootstrap_external>", line 1322, in is_package
  File "<frozen importlib._bootstrap_external>", line 134, in _path_split
  File "<frozen importlib._bootstrap_external>", line 134, in <genexpr>
AttributeError: 'NoneType' object has no attribute 'rfind'

======================================================================
ERROR: test_is_package (test.test_importlib.extension.test_loader.Source_LoaderTests.test_is_package)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 86, in test_is_package
    self.assertFalse(self.loader.is_package(util.EXTENSIONS.name))
                     ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^
  File "/Lib/importlib/_bootstrap_external.py", line 1322, in is_package
    file_name = _path_split(self.path)[1]
                ~~~~~~~~~~~^^^^^^^^^^^
  File "/Lib/importlib/_bootstrap_external.py", line 134, in _path_split
    i = max(path.rfind(p) for p in path_separators)
        ~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Lib/importlib/_bootstrap_external.py", line 134, in <genexpr>
    i = max(path.rfind(p) for p in path_separators)
            ^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'rfind'

======================================================================
ERROR: test_load_module_API (test.test_importlib.extension.test_loader.Source_LoaderTests.test_load_module_API)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 48, in test_load_module_API
    self.loader.load_module()
    ~~~~~~~~~~~~~~~~~~~~~~~^^
  File "/Lib/importlib/_bootstrap_external.py", line 668, in _check_name_wrapper
    return method(self, name, *args, **kwargs)
           ~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Lib/importlib/_bootstrap_external.py", line 1195, in load_module
    return super(FileLoader, self).load_module(fullname)
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^
  File "/Lib/importlib/_bootstrap_external.py", line 1019, in load_module
    return _bootstrap._load_module_shim(self, fullname)
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^
  File "/Lib/importlib/_bootstrap.py", line 531, in _load_module_shim
    spec = spec_from_loader(fullname, self)
           ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^
  File "/Lib/importlib/_bootstrap.py", line 673, in spec_from_loader
    return spec_from_file_location(name, loader=loader)
           ~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^
  File "/Lib/importlib/_bootstrap_external.py", line 875, in spec_from_file_location
    is_package = loader.is_package(name)
                 ~~~~~~~~~~~~~~~~~^^^^^^
  File "/Lib/importlib/_bootstrap_external.py", line 1322, in is_package
    file_name = _path_split(self.path)[1]
                ~~~~~~~~~~~^^^^^^^^^^^
  File "/Lib/importlib/_bootstrap_external.py", line 134, in _path_split
    i = max(path.rfind(p) for p in path_separators)
        ~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Lib/importlib/_bootstrap_external.py", line 134, in <genexpr>
    i = max(path.rfind(p) for p in path_separators)
            ^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'rfind'

======================================================================
ERROR: test_module (test.test_importlib.extension.test_loader.Source_LoaderTests.test_module)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 55, in test_module
    module = self.load_module(util.EXTENSIONS.name)
             ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^
  File "/Lib/test/test_importlib/extension/test_loader.py", line 32, in load_module
    return self.loader.load_module(fullname)
           ~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^
  File "/Lib/importlib/_bootstrap_external.py", line 668, in _check_name_wrapper
    return method(self, name, *args, **kwargs)
           ~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Lib/importlib/_bootstrap_external.py", line 1195, in load_module
    return super(FileLoader, self).load_module(fullname)
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^
  File "/Lib/importlib/_bootstrap_external.py", line 1019, in load_module
    return _bootstrap._load_module_shim(self, fullname)
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^
  File "/Lib/importlib/_bootstrap.py", line 531, in _load_module_shim
    spec = spec_from_loader(fullname, self)
           ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^
  File "/Lib/importlib/_bootstrap.py", line 673, in spec_from_loader
    return spec_from_file_location(name, loader=loader)
           ~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^
  File "/Lib/importlib/_bootstrap_external.py", line 875, in spec_from_file_location
    is_package = loader.is_package(name)
                 ~~~~~~~~~~~~~~~~~^^^^^^
  File "/Lib/importlib/_bootstrap_external.py", line 1322, in is_package
    file_name = _path_split(self.path)[1]
                ~~~~~~~~~~~^^^^^^^^^^^
  File "/Lib/importlib/_bootstrap_external.py", line 134, in _path_split
    i = max(path.rfind(p) for p in path_separators)
        ~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Lib/importlib/_bootstrap_external.py", line 134, in <genexpr>
    i = max(path.rfind(p) for p in path_separators)
            ^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'rfind'

======================================================================
ERROR: test_module_reuse (test.test_importlib.extension.test_loader.Source_LoaderTests.test_module_reuse)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 81, in test_module_reuse
    module1 = self.load_module(util.EXTENSIONS.name)
              ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^
  File "/Lib/test/test_importlib/extension/test_loader.py", line 32, in load_module
    return self.loader.load_module(fullname)
           ~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^
  File "/Lib/importlib/_bootstrap_external.py", line 668, in _check_name_wrapper
    return method(self, name, *args, **kwargs)
           ~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Lib/importlib/_bootstrap_external.py", line 1195, in load_module
    return super(FileLoader, self).load_module(fullname)
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^
  File "/Lib/importlib/_bootstrap_external.py", line 1019, in load_module
    return _bootstrap._load_module_shim(self, fullname)
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^
  File "/Lib/importlib/_bootstrap.py", line 531, in _load_module_shim
    spec = spec_from_loader(fullname, self)
           ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^
  File "/Lib/importlib/_bootstrap.py", line 673, in spec_from_loader
    return spec_from_file_location(name, loader=loader)
           ~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^
  File "/Lib/importlib/_bootstrap_external.py", line 875, in spec_from_file_location
    is_package = loader.is_package(name)
                 ~~~~~~~~~~~~~~~~~^^^^^^
  File "/Lib/importlib/_bootstrap_external.py", line 1322, in is_package
    file_name = _path_split(self.path)[1]
                ~~~~~~~~~~~^^^^^^^^^^^
  File "/Lib/importlib/_bootstrap_external.py", line 134, in _path_split
    i = max(path.rfind(p) for p in path_separators)
        ~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Lib/importlib/_bootstrap_external.py", line 134, in <genexpr>
    i = max(path.rfind(p) for p in path_separators)
            ^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'rfind'

======================================================================
FAIL: test_module (test.test_importlib.extension.test_finder.Frozen_FinderTests.test_module)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_finder.py", line 29, in test_module
    self.assertTrue(self.find_spec(util.EXTENSIONS.name))
    ~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: None is not true

======================================================================
FAIL: test_module (test.test_importlib.extension.test_finder.Source_FinderTests.test_module)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_finder.py", line 29, in test_module
    self.assertTrue(self.find_spec(util.EXTENSIONS.name))
    ~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: None is not true

======================================================================
FAIL: test_bad_modules (test.test_importlib.extension.test_loader.Frozen_MultiPhaseExtensionModuleTests.test_bad_modules)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 192, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_functionality (test.test_importlib.extension.test_loader.Frozen_MultiPhaseExtensionModuleTests.test_functionality)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 192, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_load_short_name (test.test_importlib.extension.test_loader.Frozen_MultiPhaseExtensionModuleTests.test_load_short_name)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 192, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_load_submodule (test.test_importlib.extension.test_loader.Frozen_MultiPhaseExtensionModuleTests.test_load_submodule)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 192, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_load_twice (test.test_importlib.extension.test_loader.Frozen_MultiPhaseExtensionModuleTests.test_load_twice)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 192, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_module (test.test_importlib.extension.test_loader.Frozen_MultiPhaseExtensionModuleTests.test_module)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 192, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_nonascii (test.test_importlib.extension.test_loader.Frozen_MultiPhaseExtensionModuleTests.test_nonascii)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 192, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_nonmodule (test.test_importlib.extension.test_loader.Frozen_MultiPhaseExtensionModuleTests.test_nonmodule)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 192, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_nonmodule_with_methods (test.test_importlib.extension.test_loader.Frozen_MultiPhaseExtensionModuleTests.test_nonmodule_with_methods)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 192, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_null_slots (test.test_importlib.extension.test_loader.Frozen_MultiPhaseExtensionModuleTests.test_null_slots)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 192, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_reload (test.test_importlib.extension.test_loader.Frozen_MultiPhaseExtensionModuleTests.test_reload)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 192, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_try_registration (test.test_importlib.extension.test_loader.Frozen_MultiPhaseExtensionModuleTests.test_try_registration)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 192, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_unloadable (test.test_importlib.extension.test_loader.Frozen_MultiPhaseExtensionModuleTests.test_unloadable)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 192, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_unloadable_nonascii (test.test_importlib.extension.test_loader.Frozen_MultiPhaseExtensionModuleTests.test_unloadable_nonascii)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 192, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_module (test.test_importlib.extension.test_loader.Frozen_SinglePhaseExtensionModuleTests.test_module)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 111, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_unloadable (test.test_importlib.extension.test_loader.Frozen_SinglePhaseExtensionModuleTests.test_unloadable)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 111, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_unloadable_nonascii (test.test_importlib.extension.test_loader.Frozen_SinglePhaseExtensionModuleTests.test_unloadable_nonascii)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 111, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_bad_modules (test.test_importlib.extension.test_loader.Source_MultiPhaseExtensionModuleTests.test_bad_modules)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 192, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_functionality (test.test_importlib.extension.test_loader.Source_MultiPhaseExtensionModuleTests.test_functionality)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 192, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_load_short_name (test.test_importlib.extension.test_loader.Source_MultiPhaseExtensionModuleTests.test_load_short_name)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 192, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_load_submodule (test.test_importlib.extension.test_loader.Source_MultiPhaseExtensionModuleTests.test_load_submodule)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 192, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_load_twice (test.test_importlib.extension.test_loader.Source_MultiPhaseExtensionModuleTests.test_load_twice)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 192, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_module (test.test_importlib.extension.test_loader.Source_MultiPhaseExtensionModuleTests.test_module)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 192, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_nonascii (test.test_importlib.extension.test_loader.Source_MultiPhaseExtensionModuleTests.test_nonascii)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 192, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_nonmodule (test.test_importlib.extension.test_loader.Source_MultiPhaseExtensionModuleTests.test_nonmodule)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 192, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_nonmodule_with_methods (test.test_importlib.extension.test_loader.Source_MultiPhaseExtensionModuleTests.test_nonmodule_with_methods)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 192, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_null_slots (test.test_importlib.extension.test_loader.Source_MultiPhaseExtensionModuleTests.test_null_slots)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 192, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_reload (test.test_importlib.extension.test_loader.Source_MultiPhaseExtensionModuleTests.test_reload)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 192, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_try_registration (test.test_importlib.extension.test_loader.Source_MultiPhaseExtensionModuleTests.test_try_registration)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 192, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_unloadable (test.test_importlib.extension.test_loader.Source_MultiPhaseExtensionModuleTests.test_unloadable)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 192, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_unloadable_nonascii (test.test_importlib.extension.test_loader.Source_MultiPhaseExtensionModuleTests.test_unloadable_nonascii)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 192, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_module (test.test_importlib.extension.test_loader.Source_SinglePhaseExtensionModuleTests.test_module)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 111, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_unloadable (test.test_importlib.extension.test_loader.Source_SinglePhaseExtensionModuleTests.test_unloadable)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 111, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_unloadable_nonascii (test.test_importlib.extension.test_loader.Source_SinglePhaseExtensionModuleTests.test_unloadable_nonascii)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/extension/test_loader.py", line 111, in setUp
    assert self.spec
           ^^^^^^^^^
AssertionError

======================================================================
FAIL: test_spec_from_file_location_smsl_default (test.test_importlib.test_spec.Frozen_FactoryTests.test_spec_from_file_location_smsl_default)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/test_spec.py", line 629, in test_spec_from_file_location_smsl_default
    self.assertEqual(spec.submodule_search_locations, [os.getcwd()])
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: Lists differ: [''] != ['/']

First differing element 0:
''
'/'

- ['']
+ ['/']
?   +


======================================================================
FAIL: test_spec_from_file_location_smsl_empty (test.test_importlib.test_spec.Frozen_FactoryTests.test_spec_from_file_location_smsl_empty)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/test_spec.py", line 604, in test_spec_from_file_location_smsl_empty
    self.assertEqual(spec.submodule_search_locations, [os.getcwd()])
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: Lists differ: [''] != ['/']

First differing element 0:
''
'/'

- ['']
+ ['/']
?   +


======================================================================
FAIL: test_spec_from_loader_is_package_true_with_fileloader (test.test_importlib.test_spec.Frozen_FactoryTests.test_spec_from_loader_is_package_true_with_fileloader)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/test_spec.py", line 505, in test_spec_from_loader_is_package_true_with_fileloader
    self.assertEqual(spec.submodule_search_locations, [os.getcwd()])
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: Lists differ: [''] != ['/']

First differing element 0:
''
'/'

- ['']
+ ['/']
?   +


======================================================================
FAIL: test_spec_from_file_location_smsl_default (test.test_importlib.test_spec.Source_FactoryTests.test_spec_from_file_location_smsl_default)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/test_spec.py", line 629, in test_spec_from_file_location_smsl_default
    self.assertEqual(spec.submodule_search_locations, [os.getcwd()])
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: Lists differ: [''] != ['/']

First differing element 0:
''
'/'

- ['']
+ ['/']
?   +


======================================================================
FAIL: test_spec_from_file_location_smsl_empty (test.test_importlib.test_spec.Source_FactoryTests.test_spec_from_file_location_smsl_empty)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/test_spec.py", line 604, in test_spec_from_file_location_smsl_empty
    self.assertEqual(spec.submodule_search_locations, [os.getcwd()])
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: Lists differ: [''] != ['/']

First differing element 0:
''
'/'

- ['']
+ ['/']
?   +


======================================================================
FAIL: test_spec_from_loader_is_package_true_with_fileloader (test.test_importlib.test_spec.Source_FactoryTests.test_spec_from_loader_is_package_true_with_fileloader)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/test_spec.py", line 505, in test_spec_from_loader_is_package_true_with_fileloader
    self.assertEqual(spec.submodule_search_locations, [os.getcwd()])
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: Lists differ: [''] != ['/']

First differing element 0:
''
'/'

- ['']
+ ['/']
?   +


======================================================================
FAIL: test_cache_from_source_respects_pycache_prefix_relative (test.test_importlib.test_util.Frozen_PEP3147Tests.test_cache_from_source_respects_pycache_prefix_relative)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/test_util.py", line 578, in test_cache_from_source_respects_pycache_prefix_relative
    self.assertEqual(
    ~~~~~~~~~~~~~~~~^
        self.util.cache_from_source(path, optimization=''),
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        expect)
        ^^^^^^^
AssertionError: '/tmp/bytecode/foo/bar/baz/qux.cpython-313.pyc' != '/tmp/bytecode/./foo/bar/baz/qux.cpython-313.pyc'
- /tmp/bytecode/foo/bar/baz/qux.cpython-313.pyc
+ /tmp/bytecode/./foo/bar/baz/qux.cpython-313.pyc
?              ++


======================================================================
FAIL: test_cache_from_source_respects_pycache_prefix_relative (test.test_importlib.test_util.Source_PEP3147Tests.test_cache_from_source_respects_pycache_prefix_relative)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/test/test_importlib/test_util.py", line 578, in test_cache_from_source_respects_pycache_prefix_relative
    self.assertEqual(
    ~~~~~~~~~~~~~~~~^
        self.util.cache_from_source(path, optimization=''),
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        expect)
        ^^^^^^^
AssertionError: '/tmp/bytecode/foo/bar/baz/qux.cpython-313.pyc' != '/tmp/bytecode/./foo/bar/baz/qux.cpython-313.pyc'
- /tmp/bytecode/foo/bar/baz/qux.cpython-313.pyc
+ /tmp/bytecode/./foo/bar/baz/qux.cpython-313.pyc
?              ++

CPython versions tested on:

CPython main branch

Operating systems tested on:

Other

Linked PRs

• GH-115979: update test_importlib to work under WASI SDK 21 #116754
• [3.12] GH-115979: update test_importlib to work under WASI SDK 21 (GH-116754) #116759
• [3.11] GH-115979: update test_importlib to work under WASI SDK 21 (GH-116754) #116762

[brettcannon]

I've started fixing this in https://github.com/brettcannon/cpython/tree/issue115979-test_importlib-wasi-sdk-21 .