1 files changed, 140 insertions, 0 deletions
diff --git a/Lib/test/test_importlib/util.py b/Lib/test/test_importlib/util.py
new file mode 100644
index 0000000..ef32f7d
--- /dev/null
+++ b/Lib/test/test_importlib/util.py
@@ -0,0 +1,140 @@
+from contextlib import contextmanager
+import imp
+import os.path
+from test import support
+import unittest
+import sys
+
+
+CASE_INSENSITIVE_FS = True
+# Windows is the only OS that is *always* case-insensitive
+# (OS X *can* be case-sensitive).
+if sys.platform not in ('win32', 'cygwin'):
+    changed_name = __file__.upper()
+    if changed_name == __file__:
+        changed_name = __file__.lower()
+    if not os.path.exists(changed_name):
+        CASE_INSENSITIVE_FS = False
+
+
+def case_insensitive_tests(test):
+    """Class decorator that nullifies tests requiring a case-insensitive
+    file system."""
+    return unittest.skipIf(not CASE_INSENSITIVE_FS,
+                            "requires a case-insensitive filesystem")(test)
+
+
+@contextmanager
+def uncache(*names):
+    """Uncache a module from sys.modules.
+
+    A basic sanity check is performed to prevent uncaching modules that either
+    cannot/shouldn't be uncached.
+
+    """
+    for name in names:
+        if name in ('sys', 'marshal', 'imp'):
+            raise ValueError(
+                "cannot uncache {0}".format(name))
+        try:
+            del sys.modules[name]
+        except KeyError:
+            pass
+    try:
+        yield
+    finally:
+        for name in names:
+            try:
+                del sys.modules[name]
+            except KeyError:
+                pass
+
+@contextmanager
+def import_state(**kwargs):
+    """Context manager to manage the various importers and stored state in the
+    sys module.
+
+    The 'modules' attribute is not supported as the interpreter state stores a
+    pointer to the dict that the interpreter uses internally;
+    reassigning to sys.modules does not have the desired effect.
+
+    """
+    originals = {}
+    try:
+        for attr, default in (('meta_path', []), ('path', []),
+                              ('path_hooks', []),
+                              ('path_importer_cache', {})):
+            originals[attr] = getattr(sys, attr)
+            if attr in kwargs:
+                new_value = kwargs[attr]
+                del kwargs[attr]
+            else:
+                new_value = default
+            setattr(sys, attr, new_value)
+        if len(kwargs):
+            raise ValueError(
+                    'unrecognized arguments: {0}'.format(kwargs.keys()))
+        yield
+    finally:
+        for attr, value in originals.items():
+            setattr(sys, attr, value)
+
+
+class mock_modules:
+
+    """A mock importer/loader."""
+
+    def __init__(self, *names, module_code={}):
+        self.modules = {}
+        self.module_code = {}
+        for name in names:
+            if not name.endswith('.__init__'):
+                import_name = name
+            else:
+                import_name = name[:-len('.__init__')]
+            if '.' not in name:
+                package = None
+            elif import_name == name:
+                package = name.rsplit('.', 1)[0]
+            else:
+                package = import_name
+            module = imp.new_module(import_name)
+            module.__loader__ = self
+            module.__file__ = '<mock __file__>'
+            module.__package__ = package
+            module.attr = name
+            if import_name != name:
+                module.__path__ = ['<mock __path__>']
+            self.modules[import_name] = module
+            if import_name in module_code:
+                self.module_code[import_name] = module_code[import_name]
+
+    def __getitem__(self, name):
+        return self.modules[name]
+
+    def find_module(self, fullname, path=None):
+        if fullname not in self.modules:
+            return None
+        else:
+            return self
+
+    def load_module(self, fullname):
+        if fullname not in self.modules:
+            raise ImportError
+        else:
+            sys.modules[fullname] = self.modules[fullname]
+            if fullname in self.module_code:
+                try:
+                    self.module_code[fullname]()
+                except Exception:
+                    del sys.modules[fullname]
+                    raise
+            return self.modules[fullname]
+
+    def __enter__(self):
+        self._uncache = uncache(*self.modules.keys())
+        self._uncache.__enter__()
+        return self
+
+    def __exit__(self, *exc_info):
+        self._uncache.__exit__(None, None, None)