test: move import_helper out

Author: deantvv

Lib/test/support/__init__.py

@@ -79,9 +79,7 @@
     # exceptions
     "Error", "TestFailed", "TestDidNotRun", "ResourceDenied",
     # imports
-    "import_module", "import_fresh_module", "CleanImport",
     # modules
-    "unload", "forget",
     # io
     "record_original_stdout", "get_original_stdout", "captured_stdout",
     "captured_stdin", "captured_stderr",
@@ -198,21 +196,6 @@ class ResourceDenied(unittest.SkipTest):
     and unexpected skips.
     """
 
-@contextlib.contextmanager
-def _ignore_deprecated_imports(ignore=True):
-    """Context manager to suppress package and module deprecation
-    warnings when importing them.
-
-    If ignore is False, this context manager has no effect.
-    """
-    if ignore:
-        with warnings.catch_warnings():
-            warnings.filterwarnings("ignore", ".+ (module|package)",
-                                    DeprecationWarning)
-            yield
-    else:
-        yield
-
 
 def ignore_warnings(*, category):
     """Decorator to suppress deprecation warnings.
@@ -230,52 +213,6 @@ def wrapper(self, *args, **kwargs):
     return decorator
 
 
-def import_module(name, deprecated=False, *, required_on=()):
-    """Import and return the module to be tested, raising SkipTest if
-    it is not available.
-
-    If deprecated is True, any module or package deprecation messages
-    will be suppressed. If a module is required on a platform but optional for
-    others, set required_on to an iterable of platform prefixes which will be
-    compared against sys.platform.
-    """
-    with _ignore_deprecated_imports(deprecated):
-        try:
-            return importlib.import_module(name)
-        except ImportError as msg:
-            if sys.platform.startswith(tuple(required_on)):
-                raise
-            raise unittest.SkipTest(str(msg))
-
-
-def _save_and_remove_module(name, orig_modules):
-    """Helper function to save and remove a module from sys.modules
-
-    Raise ImportError if the module can't be imported.
-    """
-    # try to import the module and raise an error if it can't be imported
-    if name not in sys.modules:
-        __import__(name)
-        del sys.modules[name]
-    for modname in list(sys.modules):
-        if modname == name or modname.startswith(name + '.'):
-            orig_modules[modname] = sys.modules[modname]
-            del sys.modules[modname]
-
-def _save_and_block_module(name, orig_modules):
-    """Helper function to save and block a module in sys.modules
-
-    Return True if the module was in sys.modules, False otherwise.
-    """
-    saved = True
-    try:
-        orig_modules[name] = sys.modules[name]
-    except KeyError:
-        saved = False
-    sys.modules[name] = None
-    return saved
-
-
 def anticipate_failure(condition):
     """Decorator to mark a test that is known to be broken in some cases
 
@@ -304,56 +241,6 @@ def load_tests(*args):
     return standard_tests
 
 
-def import_fresh_module(name, fresh=(), blocked=(), deprecated=False):
-    """Import and return a module, deliberately bypassing sys.modules.
-
-    This function imports and returns a fresh copy of the named Python module
-    by removing the named module from sys.modules before doing the import.
-    Note that unlike reload, the original module is not affected by
-    this operation.
-
-    *fresh* is an iterable of additional module names that are also removed
-    from the sys.modules cache before doing the import.
-
-    *blocked* is an iterable of module names that are replaced with None
-    in the module cache during the import to ensure that attempts to import
-    them raise ImportError.
-
-    The named module and any modules named in the *fresh* and *blocked*
-    parameters are saved before starting the import and then reinserted into
-    sys.modules when the fresh import is complete.
-
-    Module and package deprecation messages are suppressed during this import
-    if *deprecated* is True.
-
-    This function will raise ImportError if the named module cannot be
-    imported.
-    """
-    # NOTE: test_heapq, test_json and test_warnings include extra sanity checks
-    # to make sure that this utility function is working as expected
-    with _ignore_deprecated_imports(deprecated):
-        # Keep track of modules saved for later restoration as well
-        # as those which just need a blocking entry removed
-        orig_modules = {}
-        names_to_remove = []
-        _save_and_remove_module(name, orig_modules)
-        try:
-            for fresh_name in fresh:
-                _save_and_remove_module(fresh_name, orig_modules)
-            for blocked_name in blocked:
-                if not _save_and_block_module(blocked_name, orig_modules):
-                    names_to_remove.append(blocked_name)
-            fresh_module = importlib.import_module(name)
-        except ImportError:
-            fresh_module = None
-        finally:
-            for orig_name, module in orig_modules.items():
-                sys.modules[orig_name] = module
-            for name_to_remove in names_to_remove:
-                del sys.modules[name_to_remove]
-        return fresh_module
-
-
 def get_attribute(obj, name):
     """Get an attribute, raising SkipTest if AttributeError is raised."""
     try:
@@ -382,12 +269,6 @@ def record_original_stdout(stdout):
 def get_original_stdout():
     return _original_stdout or sys.stdout
 
-def unload(name):
-    try:
-        del sys.modules[name]
-    except KeyError:
-        pass
-
 def _force_run(path, func, *args):
     try:
         return func(*args)
@@ -528,34 +409,6 @@ def rmtree(path):
     except FileNotFoundError:
         pass
 
-def make_legacy_pyc(source):
-    """Move a PEP 3147/488 pyc file to its legacy pyc location.
-
-    :param source: The file system path to the source file.  The source file
-        does not need to exist, however the PEP 3147/488 pyc file must exist.
-    :return: The file system path to the legacy pyc file.
-    """
-    pyc_file = importlib.util.cache_from_source(source)
-    up_one = os.path.dirname(os.path.abspath(source))
-    legacy_pyc = os.path.join(up_one, source + 'c')
-    os.rename(pyc_file, legacy_pyc)
-    return legacy_pyc
-
-def forget(modname):
-    """'Forget' a module was ever imported.
-
-    This removes the module from sys.modules and deletes any PEP 3147/488 or
-    legacy .pyc files.
-    """
-    unload(modname)
-    for dirname in sys.path:
-        source = os.path.join(dirname, modname + '.py')
-        # It doesn't matter if they exist or not, unlink all possible
-        # combinations of PEP 3147/488 and legacy pyc files.
-        unlink(source + 'c')
-        for opt in ('', 1, 2):
-            unlink(importlib.util.cache_from_source(source, optimization=opt))
-
 # Check whether a gui is actually available
 def _is_gui_available():
     if hasattr(_is_gui_available, 'result'):
@@ -1225,62 +1078,6 @@ def check_no_resource_warning(testcase):
         yield
 
 
-class CleanImport(object):
-    """Context manager to force import to return a new module reference.
-
-    This is useful for testing module-level behaviours, such as
-    the emission of a DeprecationWarning on import.
-
-    Use like this:
-
-        with CleanImport("foo"):
-            importlib.import_module("foo") # new reference
-    """
-
-    def __init__(self, *module_names):
-        self.original_modules = sys.modules.copy()
-        for module_name in module_names:
-            if module_name in sys.modules:
-                module = sys.modules[module_name]
-                # It is possible that module_name is just an alias for
-                # another module (e.g. stub for modules renamed in 3.x).
-                # In that case, we also need delete the real module to clear
-                # the import cache.
-                if module.__name__ != module_name:
-                    del sys.modules[module.__name__]
-                del sys.modules[module_name]
-
-    def __enter__(self):
-        return self
-
-    def __exit__(self, *ignore_exc):
-        sys.modules.update(self.original_modules)
-
-
-class DirsOnSysPath(object):
-    """Context manager to temporarily add directories to sys.path.
-
-    This makes a copy of sys.path, appends any directories given
-    as positional arguments, then reverts sys.path to the copied
-    settings when the context ends.
-
-    Note that *all* sys.path modifications in the body of the
-    context manager, including replacement of the object,
-    will be reverted at the end of the block.
-    """
-
-    def __init__(self, *paths):
-        self.original_value = sys.path[:]
-        self.original_object = sys.path
-        sys.path.extend(paths)
-
-    def __enter__(self):
-        return self
-
-    def __exit__(self, *ignore_exc):
-        sys.path = self.original_object
-        sys.path[:] = self.original_value
-
 
 class TransientResource(object):
 
@@ -2024,25 +1821,6 @@ def print_warning(msg):
 # log warnings even if sys.stderr is captured temporarily by a test.
 print_warning.orig_stderr = sys.stderr
 
-def modules_setup():
-    return sys.modules.copy(),
-
-def modules_cleanup(oldmodules):
-    # Encoders/decoders are registered permanently within the internal
-    # codec cache. If we destroy the corresponding modules their
-    # globals will be set to None which will trip up the cached functions.
-    encodings = [(k, v) for k, v in sys.modules.items()
-                 if k.startswith('encodings.')]
-    sys.modules.clear()
-    sys.modules.update(encodings)
-    # XXX: This kind of problem can affect more than just encodings. In particular
-    # extension modules (such as _ssl) don't cope with reloading properly.
-    # Really, test modules should be cleaning out the test specific modules they
-    # know they added (ala test_runpy) rather than relying on this function (as
-    # test_importhooks and test_pkg do currently).
-    # Implicitly imported *real* modules should be left alone (see issue 10556).
-    sys.modules.update(oldmodules)
-
 #=======================================================================
 # Threading support to prevent reporting refleaks when running regrtest.py -R
 
@@ -2075,8 +1853,7 @@ def threading_cleanup(*original_values):
         if values == original_values:
             break
 
-        if not count:
-            # Display a warning at the first iteration
+        if not count: # Display a warning at the first iteration
             environment_altered = True
             dangling_threads = values[1]
             print_warning(f"threading_cleanup() failed to cleanup "