diff --git a/Lib/test/pickletester.py b/Lib/test/pickletester.py
index 51dd0fc..e3a929f 100644
--- a/Lib/test/pickletester.py
+++ b/Lib/test/pickletester.py
@@ -1,3 +1,4 @@
+import io
 import unittest
 import pickle
 import pickletools
@@ -842,7 +843,7 @@
         self.assertEqual(x.bar, y.bar)
 
     def test_reduce_overrides_default_reduce_ex(self):
-        for proto in 0, 1, 2:
+        for proto in protocols:
             x = REX_one()
             self.assertEqual(x._reduce_called, 0)
             s = self.dumps(x, proto)
@@ -851,7 +852,7 @@
             self.assertEqual(y._reduce_called, 0)
 
     def test_reduce_ex_called(self):
-        for proto in 0, 1, 2:
+        for proto in protocols:
             x = REX_two()
             self.assertEqual(x._proto, None)
             s = self.dumps(x, proto)
@@ -860,7 +861,7 @@
             self.assertEqual(y._proto, None)
 
     def test_reduce_ex_overrides_reduce(self):
-        for proto in 0, 1, 2:
+        for proto in protocols:
             x = REX_three()
             self.assertEqual(x._proto, None)
             s = self.dumps(x, proto)
@@ -869,7 +870,7 @@
             self.assertEqual(y._proto, None)
 
     def test_reduce_ex_calls_base(self):
-        for proto in 0, 1, 2:
+        for proto in protocols:
             x = REX_four()
             self.assertEqual(x._proto, None)
             s = self.dumps(x, proto)
@@ -878,7 +879,7 @@
             self.assertEqual(y._proto, proto)
 
     def test_reduce_calls_base(self):
-        for proto in 0, 1, 2:
+        for proto in protocols:
             x = REX_five()
             self.assertEqual(x._reduce_called, 0)
             s = self.dumps(x, proto)
@@ -917,6 +918,20 @@
             except (pickle.PickleError):
                 pass
 
+    def test_many_puts_and_gets(self):
+        # Test that internal data structures correctly deal with lots of
+        # puts/gets.
+        keys = ("aaa" + str(i) for i in range(100))
+        large_dict = dict((k, [4, 5, 6]) for k in keys)
+        obj = [dict(large_dict), dict(large_dict), dict(large_dict)]
+
+        for proto in protocols:
+            dumped = self.dumps(obj, proto)
+            loaded = self.loads(dumped)
+            self.assertEqual(loaded, obj,
+                             "Failed protocol %d: %r != %r"
+                             % (proto, obj, loaded))
+
 # Test classes for reduce_ex
 
 class REX_one(object):
@@ -1002,6 +1017,7 @@
     def __getattr__(self, key):
         self.foo
 
+
 class AbstractPickleModuleTests(unittest.TestCase):
 
     def test_dump_closed_file(self):
@@ -1022,13 +1038,20 @@
         finally:
             os.remove(TESTFN)
 
+    def test_load_from_and_dump_to_file(self):
+        stream = io.BytesIO()
+        data = [123, {}, 124]
+        pickle.dump(data, stream)
+        stream.seek(0)
+        unpickled = pickle.load(stream)
+        self.assertEqual(unpickled, data)
+
     def test_highest_protocol(self):
         # Of course this needs to be changed when HIGHEST_PROTOCOL changes.
         self.assertEqual(pickle.HIGHEST_PROTOCOL, 3)
 
     def test_callapi(self):
-        from io import BytesIO
-        f = BytesIO()
+        f = io.BytesIO()
         # With and without keyword arguments
         pickle.dump(123, f, -1)
         pickle.dump(123, file=f, protocol=-1)
@@ -1039,7 +1062,6 @@
 
     def test_bad_init(self):
         # Test issue3664 (pickle can segfault from a badly initialized Pickler).
-        from io import BytesIO
         # Override initialization without calling __init__() of the superclass.
         class BadPickler(pickle.Pickler):
             def __init__(self): pass
@@ -1091,6 +1113,121 @@
         self.assertEqual(self.id_count, 5)
         self.assertEqual(self.load_count, 5)
 
+
+class AbstractPicklerUnpicklerObjectTests(unittest.TestCase):
+
+    pickler_class = None
+    unpickler_class = None
+
+    def setUp(self):
+        assert self.pickler_class
+        assert self.unpickler_class
+
+    def test_clear_pickler_memo(self):
+        # To test whether clear_memo() has any effect, we pickle an object,
+        # then pickle it again without clearing the memo; the two serialized
+        # forms should be different. If we clear_memo() and then pickle the
+        # object again, the third serialized form should be identical to the
+        # first one we obtained.
+        data = ["abcdefg", "abcdefg", 44]
+        f = io.BytesIO()
+        pickler = self.pickler_class(f)
+
+        pickler.dump(data)
+        first_pickled = f.getvalue()
+
+        # Reset StringIO object.
+        f.seek(0)
+        f.truncate()
+
+        pickler.dump(data)
+        second_pickled = f.getvalue()
+
+        # Reset the Pickler and StringIO objects.
+        pickler.clear_memo()
+        f.seek(0)
+        f.truncate()
+
+        pickler.dump(data)
+        third_pickled = f.getvalue()
+
+        self.assertNotEqual(first_pickled, second_pickled)
+        self.assertEqual(first_pickled, third_pickled)
+
+    def test_priming_pickler_memo(self):
+        # Verify that we can set the Pickler's memo attribute.
+        data = ["abcdefg", "abcdefg", 44]
+        f = io.BytesIO()
+        pickler = self.pickler_class(f)
+
+        pickler.dump(data)
+        first_pickled = f.getvalue()
+
+        f = io.BytesIO()
+        primed = self.pickler_class(f)
+        primed.memo = pickler.memo
+
+        primed.dump(data)
+        primed_pickled = f.getvalue()
+
+        self.assertNotEqual(first_pickled, primed_pickled)
+
+    def test_priming_unpickler_memo(self):
+        # Verify that we can set the Unpickler's memo attribute.
+        data = ["abcdefg", "abcdefg", 44]
+        f = io.BytesIO()
+        pickler = self.pickler_class(f)
+
+        pickler.dump(data)
+        first_pickled = f.getvalue()
+
+        f = io.BytesIO()
+        primed = self.pickler_class(f)
+        primed.memo = pickler.memo
+
+        primed.dump(data)
+        primed_pickled = f.getvalue()
+
+        unpickler = self.unpickler_class(io.BytesIO(first_pickled))
+        unpickled_data1 = unpickler.load()
+
+        self.assertEqual(unpickled_data1, data)
+
+        primed = self.unpickler_class(io.BytesIO(primed_pickled))
+        primed.memo = unpickler.memo
+        unpickled_data2 = primed.load()
+
+        primed.memo.clear()
+
+        self.assertEqual(unpickled_data2, data)
+        self.assertTrue(unpickled_data2 is unpickled_data1)
+
+    def test_reusing_unpickler_objects(self):
+        data1 = ["abcdefg", "abcdefg", 44]
+        f = io.BytesIO()
+        pickler = self.pickler_class(f)
+        pickler.dump(data1)
+        pickled1 = f.getvalue()
+
+        data2 = ["abcdefg", 44, 44]
+        f = io.BytesIO()
+        pickler = self.pickler_class(f)
+        pickler.dump(data2)
+        pickled2 = f.getvalue()
+
+        f = io.BytesIO()
+        f.write(pickled1)
+        f.seek(0)
+        unpickler = self.unpickler_class(f)
+        self.assertEqual(unpickler.load(), data1)
+
+        f.seek(0)
+        f.truncate()
+        f.write(pickled2)
+        f.seek(0)
+        self.assertEqual(unpickler.load(), data2)
+
+
 if __name__ == "__main__":
     # Print some stuff that can be used to rewrite DATA{0,1,2}
     from pickletools import dis