3 files changed, 190 insertions, 0 deletions
diff --git a/Lib/test/test_dict.py b/Lib/test/test_dict.py
index 308143d..1c9bca8 100644
--- a/Lib/test/test_dict.py
+++ b/Lib/test/test_dict.py
@@ -665,6 +665,104 @@ class DictTest(unittest.TestCase):
             gc.collect()
             self.assert_(ref() is None, "Cycle was not collected")
 
+    def _not_tracked(self, t):
+        # Nested containers can take several collections to untrack
+        gc.collect()
+        gc.collect()
+        self.assertFalse(gc.is_tracked(t), t)
+
+    def _tracked(self, t):
+        self.assertTrue(gc.is_tracked(t), t)
+        gc.collect()
+        gc.collect()
+        self.assertTrue(gc.is_tracked(t), t)
+
+    def test_track_literals(self):
+        # Test GC-optimization of dict literals
+        x, y, z, w = 1.5, "a", (1, None), []
+
+        self._not_tracked({})
+        self._not_tracked({x:(), y:x, z:1})
+        self._not_tracked({1: "a", "b": 2})
+        self._not_tracked({1: 2, (None, True, False, ()): int})
+        self._not_tracked({1: object()})
+
+        # Dicts with mutable elements are always tracked, even if those
+        # elements are not tracked right now.
+        self._tracked({1: []})
+        self._tracked({1: ([],)})
+        self._tracked({1: {}})
+        self._tracked({1: set()})
+
+    def test_track_dynamic(self):
+        # Test GC-optimization of dynamically-created dicts
+        class MyObject(object):
+            pass
+        x, y, z, w, o = 1.5, "a", (1, object()), [], MyObject()
+
+        d = dict()
+        self._not_tracked(d)
+        d[1] = "a"
+        self._not_tracked(d)
+        d[y] = 2
+        self._not_tracked(d)
+        d[z] = 3
+        self._not_tracked(d)
+        self._not_tracked(d.copy())
+        d[4] = w
+        self._tracked(d)
+        self._tracked(d.copy())
+        d[4] = None
+        self._not_tracked(d)
+        self._not_tracked(d.copy())
+
+        # dd isn't tracked right now, but it may mutate and therefore d
+        # which contains it must be tracked.
+        d = dict()
+        dd = dict()
+        d[1] = dd
+        self._not_tracked(dd)
+        self._tracked(d)
+        dd[1] = d
+        self._tracked(dd)
+
+        d = dict.fromkeys([x, y, z])
+        self._not_tracked(d)
+        dd = dict()
+        dd.update(d)
+        self._not_tracked(dd)
+        d = dict.fromkeys([x, y, z, o])
+        self._tracked(d)
+        dd = dict()
+        dd.update(d)
+        self._tracked(dd)
+
+        d = dict(x=x, y=y, z=z)
+        self._not_tracked(d)
+        d = dict(x=x, y=y, z=z, w=w)
+        self._tracked(d)
+        d = dict()
+        d.update(x=x, y=y, z=z)
+        self._not_tracked(d)
+        d.update(w=w)
+        self._tracked(d)
+
+        d = dict([(x, y), (z, 1)])
+        self._not_tracked(d)
+        d = dict([(x, y), (z, w)])
+        self._tracked(d)
+        d = dict()
+        d.update([(x, y), (z, 1)])
+        self._not_tracked(d)
+        d.update([(x, y), (z, w)])
+        self._tracked(d)
+
+    def test_track_subtypes(self):
+        # Dict subtypes are always tracked
+        class MyDict(dict):
+            pass
+        self._tracked(MyDict())
+
 
 from test import mapping_tests
 
diff --git a/Lib/test/test_gc.py b/Lib/test/test_gc.py
index 414e17a..2262b36 100644
--- a/Lib/test/test_gc.py
+++ b/Lib/test/test_gc.py
@@ -415,6 +415,33 @@ class GCTests(unittest.TestCase):
 
         self.assertEqual(gc.get_referents(1, 'a', 4j), [])
 
+    def test_is_tracked(self):
+        # Atomic built-in types are not tracked, user-defined objects and
+        # mutable containers are.
+        # NOTE: types with special optimizations (e.g. tuple) have tests
+        # in their own test files instead.
+        self.assertFalse(gc.is_tracked(None))
+        self.assertFalse(gc.is_tracked(1))
+        self.assertFalse(gc.is_tracked(1.0))
+        self.assertFalse(gc.is_tracked(1.0 + 5.0j))
+        self.assertFalse(gc.is_tracked(True))
+        self.assertFalse(gc.is_tracked(False))
+        self.assertFalse(gc.is_tracked(b"a"))
+        self.assertFalse(gc.is_tracked("a"))
+        self.assertFalse(gc.is_tracked(bytearray(b"a")))
+        self.assertFalse(gc.is_tracked(type))
+        self.assertFalse(gc.is_tracked(int))
+        self.assertFalse(gc.is_tracked(object))
+        self.assertFalse(gc.is_tracked(object()))
+
+        class UserClass:
+            pass
+        self.assertTrue(gc.is_tracked(gc))
+        self.assertTrue(gc.is_tracked(UserClass))
+        self.assertTrue(gc.is_tracked(UserClass()))
+        self.assertTrue(gc.is_tracked([]))
+        self.assertTrue(gc.is_tracked(set()))
+
     def test_bug1055820b(self):
         # Corresponds to temp2b.py in the bug report.
 
diff --git a/Lib/test/test_tuple.py b/Lib/test/test_tuple.py
index de08131..f82af31 100644
--- a/Lib/test/test_tuple.py
+++ b/Lib/test/test_tuple.py
@@ -1,5 +1,7 @@
 from test import support, seq_tests
 
+import gc
+
 class TupleTest(seq_tests.CommonTest):
     type2test = tuple
 
@@ -82,6 +84,69 @@ class TupleTest(seq_tests.CommonTest):
         self.assertEqual(repr(a0), "()")
         self.assertEqual(repr(a2), "(0, 1, 2)")
 
+    def _not_tracked(self, t):
+        # Nested tuples can take several collections to untrack
+        gc.collect()
+        gc.collect()
+        self.assertFalse(gc.is_tracked(t), t)
+
+    def _tracked(self, t):
+        self.assertTrue(gc.is_tracked(t), t)
+        gc.collect()
+        gc.collect()
+        self.assertTrue(gc.is_tracked(t), t)
+
+    def test_track_literals(self):
+        # Test GC-optimization of tuple literals
+        x, y, z = 1.5, "a", []
+
+        self._not_tracked(())
+        self._not_tracked((1,))
+        self._not_tracked((1, 2))
+        self._not_tracked((1, 2, "a"))
+        self._not_tracked((1, 2, (None, True, False, ()), int))
+        self._not_tracked((object(),))
+        self._not_tracked(((1, x), y, (2, 3)))
+
+        # Tuples with mutable elements are always tracked, even if those
+        # elements are not tracked right now.
+        self._tracked(([],))
+        self._tracked(([1],))
+        self._tracked(({},))
+        self._tracked((set(),))
+        self._tracked((x, y, z))
+
+    def check_track_dynamic(self, tp, always_track):
+        x, y, z = 1.5, "a", []
+
+        check = self._tracked if always_track else self._not_tracked
+        check(tp())
+        check(tp([]))
+        check(tp(set()))
+        check(tp([1, x, y]))
+        check(tp(obj for obj in [1, x, y]))
+        check(tp(set([1, x, y])))
+        check(tp(tuple([obj]) for obj in [1, x, y]))
+        check(tuple(tp([obj]) for obj in [1, x, y]))
+
+        self._tracked(tp([z]))
+        self._tracked(tp([[x, y]]))
+        self._tracked(tp([{x: y}]))
+        self._tracked(tp(obj for obj in [x, y, z]))
+        self._tracked(tp(tuple([obj]) for obj in [x, y, z]))
+        self._tracked(tuple(tp([obj]) for obj in [x, y, z]))
+
+    def test_track_dynamic(self):
+        # Test GC-optimization of dynamically constructed tuples.
+        self.check_track_dynamic(tuple, False)
+
+    def test_track_subtypes(self):
+        # Tuple subtypes must always be tracked
+        class MyTuple(tuple):
+            pass
+        self.check_track_dynamic(MyTuple, True)
+
+
 def test_main():
     support.run_unittest(TupleTest)