Tests for @abstractproperty by Jeffrey Yasskin.

(The previous changes to abc.py were also by him).
Put back a comment about using super() for properties
(I didn't realize this worked).

Lib/abc.py

@@ -30,6 +30,8 @@ class abstractproperty(property):
     Requires that the metaclass is ABCMeta or derived from it.  A
     class that has a metaclass derived from ABCMeta cannot be
     instantiated unless all of its abstract properties are overridden.
+    The abstract properties can be called using any of the the normal
+    'super' call mechanisms.
 
     Usage:
 

Lib/test/test_abc.py

@@ -19,9 +19,25 @@ def foo(self): pass
         def bar(self): pass
         self.assertEqual(hasattr(bar, "__isabstractmethod__"), False)
 
-    def test_abstractmethod_integration(self):
+    def test_abstractproperty_basics(self):
+        @abc.abstractproperty
+        def foo(self): pass
+        self.assertEqual(foo.__isabstractmethod__, True)
+        def bar(self): pass
+        self.assertEqual(hasattr(bar, "__isabstractmethod__"), False)
+
         class C(metaclass=abc.ABCMeta):
-            @abc.abstractmethod
+            @abc.abstractproperty
+            def foo(self): return 3
+        class D(C):
+            @property
+            def foo(self): return super().foo
+        self.assertEqual(D().foo, 3)
+
+    def test_abstractmethod_integration(self):
+        for abstractthing in [abc.abstractmethod, abc.abstractproperty]:
+            class C(metaclass=abc.ABCMeta):
+                @abstractthing
                 def foo(self): pass  # abstract
                 def bar(self): pass  # concrete
             self.assertEqual(C.__abstractmethods__, {"foo"})
@@ -35,7 +51,7 @@ def foo(self): pass
             self.assertEqual(E.__abstractmethods__, set())
             E()  # now foo is concrete, too
             class F(E):
-            @abc.abstractmethod
+                @abstractthing
                 def bar(self): pass  # abstract override of concrete
             self.assertEqual(F.__abstractmethods__, {"bar"})
             self.assertRaises(TypeError, F)  # because bar is abstract now