Add py3k warnings for object, type, cell and dict comparisons. This should resolve issue2342 and partly resolve issue2373.

Lib/test/test_undocumented_details.py

@@ -0,0 +1,39 @@
+from test.test_support import run_unittest, have_unicode
+import unittest
+import sys
+
+class TestImplementationComparisons(unittest.TestCase):
+
+    def test_type_comparisons(self):
+        self.assertTrue(str < int or str > int)
+        self.assertTrue(int <= str or int >= str)
+        self.assertTrue(cmp(int, str) != 0)
+        self.assertTrue(int is int)
+        self.assertTrue(str == str)
+        self.assertTrue(int != str)
+
+    def test_cell_comparisons(self):
+        def f(x):
+            if x:
+                y = 1
+            def g():
+                return x
+            def h():
+                return y
+            return g, h
+        g, h = f(0)
+        g_cell, = g.func_closure
+        h_cell, = h.func_closure
+        self.assertTrue(h_cell < g_cell)
+        self.assertTrue(g_cell >= h_cell)
+        self.assertEqual(cmp(g_cell, h_cell), 1)
+        self.assertTrue(g_cell is g_cell)
+        self.assertTrue(g_cell == g_cell)
+        self.assertTrue(h_cell == h_cell)
+        self.assertTrue(g_cell != h_cell)
+
+def test_main():
+    run_unittest(TestImplementationComparisons)
+
+if __name__ == '__main__':
+    test_main()