1 files changed, 93 insertions, 0 deletions
diff --git a/lib/python2.7/test/test_typechecks.py b/lib/python2.7/test/test_typechecks.py
new file mode 100644
index 0000000..83f0114
--- /dev/null
+++ b/lib/python2.7/test/test_typechecks.py
@@ -0,0 +1,93 @@
+"""Unit tests for __instancecheck__ and __subclasscheck__."""
+
+import unittest
+from test import test_support
+
+
+class ABC(type):
+
+    def __instancecheck__(cls, inst):
+        """Implement isinstance(inst, cls)."""
+        return any(cls.__subclasscheck__(c)
+                   for c in set([type(inst), inst.__class__]))
+
+    def __subclasscheck__(cls, sub):
+        """Implement issubclass(sub, cls)."""
+        candidates = cls.__dict__.get("__subclass__", set()) | set([cls])
+        return any(c in candidates for c in sub.mro())
+
+
+class Integer:
+
+    __metaclass__ = ABC
+
+    __subclass__ = set([int])
+
+
+class SubInt(Integer):
+
+    pass
+
+
+class TypeChecksTest(unittest.TestCase):
+
+    def testIsSubclassInternal(self):
+        self.assertEqual(Integer.__subclasscheck__(int), True)
+        self.assertEqual(Integer.__subclasscheck__(float), False)
+
+    def testIsSubclassBuiltin(self):
+        self.assertEqual(issubclass(int, Integer), True)
+        self.assertEqual(issubclass(int, (Integer,)), True)
+        self.assertEqual(issubclass(float, Integer), False)
+        self.assertEqual(issubclass(float, (Integer,)), False)
+
+    def testIsInstanceBuiltin(self):
+        self.assertEqual(isinstance(42, Integer), True)
+        self.assertEqual(isinstance(42, (Integer,)), True)
+        self.assertEqual(isinstance(3.14, Integer), False)
+        self.assertEqual(isinstance(3.14, (Integer,)), False)
+
+    def testIsInstanceActual(self):
+        self.assertEqual(isinstance(Integer(), Integer), True)
+        self.assertEqual(isinstance(Integer(), (Integer,)), True)
+
+    def testIsSubclassActual(self):
+        self.assertEqual(issubclass(Integer, Integer), True)
+        self.assertEqual(issubclass(Integer, (Integer,)), True)
+
+    def testSubclassBehavior(self):
+        self.assertEqual(issubclass(SubInt, Integer), True)
+        self.assertEqual(issubclass(SubInt, (Integer,)), True)
+        self.assertEqual(issubclass(SubInt, SubInt), True)
+        self.assertEqual(issubclass(SubInt, (SubInt,)), True)
+        self.assertEqual(issubclass(Integer, SubInt), False)
+        self.assertEqual(issubclass(Integer, (SubInt,)), False)
+        self.assertEqual(issubclass(int, SubInt), False)
+        self.assertEqual(issubclass(int, (SubInt,)), False)
+        self.assertEqual(isinstance(SubInt(), Integer), True)
+        self.assertEqual(isinstance(SubInt(), (Integer,)), True)
+        self.assertEqual(isinstance(SubInt(), SubInt), True)
+        self.assertEqual(isinstance(SubInt(), (SubInt,)), True)
+        self.assertEqual(isinstance(42, SubInt), False)
+        self.assertEqual(isinstance(42, (SubInt,)), False)
+
+    def test_oldstyle(self):
+        # These should just be ignored.
+        class X:
+            def __instancecheck__(self, inst):
+                return True
+            def __subclasscheck__(self, cls):
+                return True
+        class Sub(X): pass
+        self.assertNotIsInstance(3, X)
+        self.assertIsInstance(X(), X)
+        self.assertFalse(issubclass(int, X))
+        self.assertTrue(issubclass(Sub, X))
+
+
+def test_main():
+    test_support.run_unittest(TypeChecksTest)
+
+
+if __name__ == "__main__":
+    unittest.main()