Issue #15168: Move importlb.test to test.test_importlib.

This should make the Linux distros happy as it is now easier to leave
importlib's tests out of their base Python distribution.

Lib/test/test_importlib/test_util.py

@@ -0,0 +1,208 @@
+from importlib import util
+from . import util as test_util
+import imp
+import sys
+import types
+import unittest
+
+
+class ModuleForLoaderTests(unittest.TestCase):
+
+    """Tests for importlib.util.module_for_loader."""
+
+    def return_module(self, name):
+        fxn = util.module_for_loader(lambda self, module: module)
+        return fxn(self, name)
+
+    def raise_exception(self, name):
+        def to_wrap(self, module):
+            raise ImportError
+        fxn = util.module_for_loader(to_wrap)
+        try:
+            fxn(self, name)
+        except ImportError:
+            pass
+
+    def test_new_module(self):
+        # Test that when no module exists in sys.modules a new module is
+        # created.
+        module_name = 'a.b.c'
+        with test_util.uncache(module_name):
+            module = self.return_module(module_name)
+            self.assertIn(module_name, sys.modules)
+        self.assertIsInstance(module, types.ModuleType)
+        self.assertEqual(module.__name__, module_name)
+
+    def test_reload(self):
+        # Test that a module is reused if already in sys.modules.
+        name = 'a.b.c'
+        module = imp.new_module('a.b.c')
+        with test_util.uncache(name):
+            sys.modules[name] = module
+            returned_module = self.return_module(name)
+            self.assertIs(returned_module, sys.modules[name])
+
+    def test_new_module_failure(self):
+        # Test that a module is removed from sys.modules if added but an
+        # exception is raised.
+        name = 'a.b.c'
+        with test_util.uncache(name):
+            self.raise_exception(name)
+            self.assertNotIn(name, sys.modules)
+
+    def test_reload_failure(self):
+        # Test that a failure on reload leaves the module in-place.
+        name = 'a.b.c'
+        module = imp.new_module(name)
+        with test_util.uncache(name):
+            sys.modules[name] = module
+            self.raise_exception(name)
+            self.assertIs(module, sys.modules[name])
+
+    def test_decorator_attrs(self):
+        def fxn(self, module): pass
+        wrapped = util.module_for_loader(fxn)
+        self.assertEqual(wrapped.__name__, fxn.__name__)
+        self.assertEqual(wrapped.__qualname__, fxn.__qualname__)
+
+    def test_false_module(self):
+        # If for some odd reason a module is considered false, still return it
+        # from sys.modules.
+        class FalseModule(types.ModuleType):
+            def __bool__(self): return False
+
+        name = 'mod'
+        module = FalseModule(name)
+        with test_util.uncache(name):
+            self.assertFalse(module)
+            sys.modules[name] = module
+            given = self.return_module(name)
+            self.assertIs(given, module)
+
+    def test_attributes_set(self):
+        # __name__, __loader__, and __package__ should be set (when
+        # is_package() is defined; undefined implicitly tested elsewhere).
+        class FakeLoader:
+            def __init__(self, is_package):
+                self._pkg = is_package
+            def is_package(self, name):
+                return self._pkg
+            @util.module_for_loader
+            def load_module(self, module):
+                return module
+
+        name = 'pkg.mod'
+        with test_util.uncache(name):
+            loader = FakeLoader(False)
+            module = loader.load_module(name)
+            self.assertEqual(module.__name__, name)
+            self.assertIs(module.__loader__, loader)
+            self.assertEqual(module.__package__, 'pkg')
+
+        name = 'pkg.sub'
+        with test_util.uncache(name):
+            loader = FakeLoader(True)
+            module = loader.load_module(name)
+            self.assertEqual(module.__name__, name)
+            self.assertIs(module.__loader__, loader)
+            self.assertEqual(module.__package__, name)
+
+
+class SetPackageTests(unittest.TestCase):
+
+    """Tests for importlib.util.set_package."""
+
+    def verify(self, module, expect):
+        """Verify the module has the expected value for __package__ after
+        passing through set_package."""
+        fxn = lambda: module
+        wrapped = util.set_package(fxn)
+        wrapped()
+        self.assertTrue(hasattr(module, '__package__'))
+        self.assertEqual(expect, module.__package__)
+
+    def test_top_level(self):
+        # __package__ should be set to the empty string if a top-level module.
+        # Implicitly tests when package is set to None.
+        module = imp.new_module('module')
+        module.__package__ = None
+        self.verify(module, '')
+
+    def test_package(self):
+        # Test setting __package__ for a package.
+        module = imp.new_module('pkg')
+        module.__path__ = ['<path>']
+        module.__package__ = None
+        self.verify(module, 'pkg')
+
+    def test_submodule(self):
+        # Test __package__ for a module in a package.
+        module = imp.new_module('pkg.mod')
+        module.__package__ = None
+        self.verify(module, 'pkg')
+
+    def test_setting_if_missing(self):
+        # __package__ should be set if it is missing.
+        module = imp.new_module('mod')
+        if hasattr(module, '__package__'):
+            delattr(module, '__package__')
+        self.verify(module, '')
+
+    def test_leaving_alone(self):
+        # If __package__ is set and not None then leave it alone.
+        for value in (True, False):
+            module = imp.new_module('mod')
+            module.__package__ = value
+            self.verify(module, value)
+
+    def test_decorator_attrs(self):
+        def fxn(module): pass
+        wrapped = util.set_package(fxn)
+        self.assertEqual(wrapped.__name__, fxn.__name__)
+        self.assertEqual(wrapped.__qualname__, fxn.__qualname__)
+
+
+class ResolveNameTests(unittest.TestCase):
+
+    """Tests importlib.util.resolve_name()."""
+
+    def test_absolute(self):
+        # bacon
+        self.assertEqual('bacon', util.resolve_name('bacon', None))
+
+    def test_aboslute_within_package(self):
+        # bacon in spam
+        self.assertEqual('bacon', util.resolve_name('bacon', 'spam'))
+
+    def test_no_package(self):
+        # .bacon in ''
+        with self.assertRaises(ValueError):
+            util.resolve_name('.bacon', '')
+
+    def test_in_package(self):
+        # .bacon in spam
+        self.assertEqual('spam.eggs.bacon',
+                         util.resolve_name('.bacon', 'spam.eggs'))
+
+    def test_other_package(self):
+        # ..bacon in spam.bacon
+        self.assertEqual('spam.bacon',
+                         util.resolve_name('..bacon', 'spam.eggs'))
+
+    def test_escape(self):
+        # ..bacon in spam
+        with self.assertRaises(ValueError):
+            util.resolve_name('..bacon', 'spam')
+
+
+def test_main():
+    from test import support
+    support.run_unittest(
+            ModuleForLoaderTests,
+            SetPackageTests,
+            ResolveNameTests
+        )
+
+
+if __name__ == '__main__':
+    test_main()