1 files changed, 103 insertions, 0 deletions
diff --git a/Lib/test/test_importlib/test_abc.py b/Lib/test/test_importlib/test_abc.py
new file mode 100644
index 0000000000..c620c3771b
--- /dev/null
+++ b/Lib/test/test_importlib/test_abc.py
@@ -0,0 +1,103 @@
+from importlib import abc
+from importlib import machinery
+import inspect
+import unittest
+
+
+class InheritanceTests:
+
+    """Test that the specified class is a subclass/superclass of the expected
+    classes."""
+
+    subclasses = []
+    superclasses = []
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        assert self.subclasses or self.superclasses, self.__class__
+        self.__test = getattr(abc, self.__class__.__name__)
+
+    def test_subclasses(self):
+        # Test that the expected subclasses inherit.
+        for subclass in self.subclasses:
+            self.assertTrue(issubclass(subclass, self.__test),
+                "{0} is not a subclass of {1}".format(subclass, self.__test))
+
+    def test_superclasses(self):
+        # Test that the class inherits from the expected superclasses.
+        for superclass in self.superclasses:
+            self.assertTrue(issubclass(self.__test, superclass),
+               "{0} is not a superclass of {1}".format(superclass, self.__test))
+
+
+class MetaPathFinder(InheritanceTests, unittest.TestCase):
+
+    superclasses = [abc.Finder]
+    subclasses = [machinery.BuiltinImporter, machinery.FrozenImporter,
+                    machinery.PathFinder, machinery.WindowsRegistryFinder]
+
+
+class PathEntryFinder(InheritanceTests, unittest.TestCase):
+
+    superclasses = [abc.Finder]
+    subclasses = [machinery.FileFinder]
+
+
+class Loader(InheritanceTests, unittest.TestCase):
+
+    subclasses = [abc.PyLoader]
+
+
+class ResourceLoader(InheritanceTests, unittest.TestCase):
+
+    superclasses = [abc.Loader]
+
+
+class InspectLoader(InheritanceTests, unittest.TestCase):
+
+    superclasses = [abc.Loader]
+    subclasses = [abc.PyLoader, machinery.BuiltinImporter,
+                    machinery.FrozenImporter, machinery.ExtensionFileLoader]
+
+
+class ExecutionLoader(InheritanceTests, unittest.TestCase):
+
+    superclasses = [abc.InspectLoader]
+    subclasses = [abc.PyLoader]
+
+
+class FileLoader(InheritanceTests, unittest.TestCase):
+
+    superclasses = [abc.ResourceLoader, abc.ExecutionLoader]
+    subclasses = [machinery.SourceFileLoader, machinery.SourcelessFileLoader]
+
+
+class SourceLoader(InheritanceTests, unittest.TestCase):
+
+    superclasses = [abc.ResourceLoader, abc.ExecutionLoader]
+    subclasses = [machinery.SourceFileLoader]
+
+
+class PyLoader(InheritanceTests, unittest.TestCase):
+
+    superclasses = [abc.Loader, abc.ResourceLoader, abc.ExecutionLoader]
+
+
+class PyPycLoader(InheritanceTests, unittest.TestCase):
+
+    superclasses = [abc.PyLoader]
+
+
+def test_main():
+    from test.support import run_unittest
+    classes = []
+    for class_ in globals().values():
+        if (inspect.isclass(class_) and
+                issubclass(class_, unittest.TestCase) and
+                issubclass(class_, InheritanceTests)):
+            classes.append(class_)
+    run_unittest(*classes)
+
+
+if __name__ == '__main__':
+    test_main()