diff --git a/Lib/test/test_gc.py b/Lib/test/test_gc.py
index ec470c4..4cb3402 100644
--- a/Lib/test/test_gc.py
+++ b/Lib/test/test_gc.py
@@ -1,391 +1,12 @@
-from test.test_support import verify, verbose, TestFailed, vereq
+import unittest
+from test.test_support import verbose, run_unittest
 import sys
 import gc
 import weakref
 
-def expect(actual, expected, name):
-    if actual != expected:
-        raise TestFailed, "test_%s: actual %r, expected %r" % (
-            name, actual, expected)
-
-def expect_nonzero(actual, name):
-    if actual == 0:
-        raise TestFailed, "test_%s: unexpected zero" % name
-
-def run_test(name, thunk):
-    if verbose:
-        print "testing %s..." % name,
-    thunk()
-    if verbose:
-        print "ok"
-
-def test_list():
-    l = []
-    l.append(l)
-    gc.collect()
-    del l
-    expect(gc.collect(), 1, "list")
-
-def test_dict():
-    d = {}
-    d[1] = d
-    gc.collect()
-    del d
-    expect(gc.collect(), 1, "dict")
-
-def test_tuple():
-    # since tuples are immutable we close the loop with a list
-    l = []
-    t = (l,)
-    l.append(t)
-    gc.collect()
-    del t
-    del l
-    expect(gc.collect(), 2, "tuple")
-
-def test_class():
-    class A:
-        pass
-    A.a = A
-    gc.collect()
-    del A
-    expect_nonzero(gc.collect(), "class")
-
-def test_newstyleclass():
-    class A(object):
-        pass
-    gc.collect()
-    del A
-    expect_nonzero(gc.collect(), "staticclass")
-
-def test_instance():
-    class A:
-        pass
-    a = A()
-    a.a = a
-    gc.collect()
-    del a
-    expect_nonzero(gc.collect(), "instance")
-
-def test_newinstance():
-    class A(object):
-        pass
-    a = A()
-    a.a = a
-    gc.collect()
-    del a
-    expect_nonzero(gc.collect(), "newinstance")
-    class B(list):
-        pass
-    class C(B, A):
-        pass
-    a = C()
-    a.a = a
-    gc.collect()
-    del a
-    expect_nonzero(gc.collect(), "newinstance(2)")
-    del B, C
-    expect_nonzero(gc.collect(), "newinstance(3)")
-    A.a = A()
-    del A
-    expect_nonzero(gc.collect(), "newinstance(4)")
-    expect(gc.collect(), 0, "newinstance(5)")
-
-def test_method():
-    # Tricky: self.__init__ is a bound method, it references the instance.
-    class A:
-        def __init__(self):
-            self.init = self.__init__
-    a = A()
-    gc.collect()
-    del a
-    expect_nonzero(gc.collect(), "method")
-
-def test_finalizer():
-    # A() is uncollectable if it is part of a cycle, make sure it shows up
-    # in gc.garbage.
-    class A:
-        def __del__(self): pass
-    class B:
-        pass
-    a = A()
-    a.a = a
-    id_a = id(a)
-    b = B()
-    b.b = b
-    gc.collect()
-    del a
-    del b
-    expect_nonzero(gc.collect(), "finalizer")
-    for obj in gc.garbage:
-        if id(obj) == id_a:
-            del obj.a
-            break
-    else:
-        raise TestFailed, "didn't find obj in garbage (finalizer)"
-    gc.garbage.remove(obj)
-
-def test_finalizer_newclass():
-    # A() is uncollectable if it is part of a cycle, make sure it shows up
-    # in gc.garbage.
-    class A(object):
-        def __del__(self): pass
-    class B(object):
-        pass
-    a = A()
-    a.a = a
-    id_a = id(a)
-    b = B()
-    b.b = b
-    gc.collect()
-    del a
-    del b
-    expect_nonzero(gc.collect(), "finalizer")
-    for obj in gc.garbage:
-        if id(obj) == id_a:
-            del obj.a
-            break
-    else:
-        raise TestFailed, "didn't find obj in garbage (finalizer)"
-    gc.garbage.remove(obj)
-
-def test_function():
-    # Tricky: f -> d -> f, code should call d.clear() after the exec to
-    # break the cycle.
-    d = {}
-    exec("def f(): pass\n") in d
-    gc.collect()
-    del d
-    expect(gc.collect(), 2, "function")
-
-def test_frame():
-    def f():
-        frame = sys._getframe()
-    gc.collect()
-    f()
-    expect(gc.collect(), 1, "frame")
-
-
-def test_saveall():
-    # Verify that cyclic garbage like lists show up in gc.garbage if the
-    # SAVEALL option is enabled.
-
-    # First make sure we don't save away other stuff that just happens to
-    # be waiting for collection.
-    gc.collect()
-    vereq(gc.garbage, []) # if this fails, someone else created immortal trash
-
-    L = []
-    L.append(L)
-    id_L = id(L)
-
-    debug = gc.get_debug()
-    gc.set_debug(debug | gc.DEBUG_SAVEALL)
-    del L
-    gc.collect()
-    gc.set_debug(debug)
-
-    vereq(len(gc.garbage), 1)
-    obj = gc.garbage.pop()
-    vereq(id(obj), id_L)
-
-def test_del():
-    # __del__ methods can trigger collection, make this to happen
-    thresholds = gc.get_threshold()
-    gc.enable()
-    gc.set_threshold(1)
-
-    class A:
-        def __del__(self):
-            dir(self)
-    a = A()
-    del a
-
-    gc.disable()
-    gc.set_threshold(*thresholds)
-
-def test_del_newclass():
-    # __del__ methods can trigger collection, make this to happen
-    thresholds = gc.get_threshold()
-    gc.enable()
-    gc.set_threshold(1)
-
-    class A(object):
-        def __del__(self):
-            dir(self)
-    a = A()
-    del a
-
-    gc.disable()
-    gc.set_threshold(*thresholds)
-
-def test_get_count():
-    gc.collect()
-    expect(gc.get_count(), (0, 0, 0), "get_count()")
-    a = dict()
-    expect(gc.get_count(), (1, 0, 0), "get_count()")
-
-def test_collect_generations():
-    gc.collect()
-    a = dict()
-    gc.collect(0)
-    expect(gc.get_count(), (0, 1, 0), "collect(0)")
-    gc.collect(1)
-    expect(gc.get_count(), (0, 0, 1), "collect(1)")
-    gc.collect(2)
-    expect(gc.get_count(), (0, 0, 0), "collect(1)")
-
-class Ouch:
-    n = 0
-    def __del__(self):
-        Ouch.n = Ouch.n + 1
-        if Ouch.n % 17 == 0:
-            gc.collect()
-
-def test_trashcan():
-    # "trashcan" is a hack to prevent stack overflow when deallocating
-    # very deeply nested tuples etc.  It works in part by abusing the
-    # type pointer and refcount fields, and that can yield horrible
-    # problems when gc tries to traverse the structures.
-    # If this test fails (as it does in 2.0, 2.1 and 2.2), it will
-    # most likely die via segfault.
-
-    # Note:  In 2.3 the possibility for compiling without cyclic gc was
-    # removed, and that in turn allows the trashcan mechanism to work
-    # via much simpler means (e.g., it never abuses the type pointer or
-    # refcount fields anymore).  Since it's much less likely to cause a
-    # problem now, the various constants in this expensive (we force a lot
-    # of full collections) test are cut back from the 2.2 version.
-    gc.enable()
-    N = 150
-    for count in range(2):
-        t = []
-        for i in range(N):
-            t = [t, Ouch()]
-        u = []
-        for i in range(N):
-            u = [u, Ouch()]
-        v = {}
-        for i in range(N):
-            v = {1: v, 2: Ouch()}
-    gc.disable()
-
-class Boom:
-    def __getattr__(self, someattribute):
-        del self.attr
-        raise AttributeError
-
-def test_boom():
-    a = Boom()
-    b = Boom()
-    a.attr = b
-    b.attr = a
-
-    gc.collect()
-    garbagelen = len(gc.garbage)
-    del a, b
-    # a<->b are in a trash cycle now.  Collection will invoke Boom.__getattr__
-    # (to see whether a and b have __del__ methods), and __getattr__ deletes
-    # the internal "attr" attributes as a side effect.  That causes the
-    # trash cycle to get reclaimed via refcounts falling to 0, thus mutating
-    # the trash graph as a side effect of merely asking whether __del__
-    # exists.  This used to (before 2.3b1) crash Python.  Now __getattr__
-    # isn't called.
-    expect(gc.collect(), 4, "boom")
-    expect(len(gc.garbage), garbagelen, "boom")
-
-class Boom2:
-    def __init__(self):
-        self.x = 0
-
-    def __getattr__(self, someattribute):
-        self.x += 1
-        if self.x > 1:
-            del self.attr
-        raise AttributeError
-
-def test_boom2():
-    a = Boom2()
-    b = Boom2()
-    a.attr = b
-    b.attr = a
-
-    gc.collect()
-    garbagelen = len(gc.garbage)
-    del a, b
-    # Much like test_boom(), except that __getattr__ doesn't break the
-    # cycle until the second time gc checks for __del__.  As of 2.3b1,
-    # there isn't a second time, so this simply cleans up the trash cycle.
-    # We expect a, b, a.__dict__ and b.__dict__ (4 objects) to get reclaimed
-    # this way.
-    expect(gc.collect(), 4, "boom2")
-    expect(len(gc.garbage), garbagelen, "boom2")
-
-# boom__new and boom2_new are exactly like boom and boom2, except use
-# new-style classes.
-
-class Boom_New(object):
-    def __getattr__(self, someattribute):
-        del self.attr
-        raise AttributeError
-
-def test_boom_new():
-    a = Boom_New()
-    b = Boom_New()
-    a.attr = b
-    b.attr = a
-
-    gc.collect()
-    garbagelen = len(gc.garbage)
-    del a, b
-    expect(gc.collect(), 4, "boom_new")
-    expect(len(gc.garbage), garbagelen, "boom_new")
-
-class Boom2_New(object):
-    def __init__(self):
-        self.x = 0
-
-    def __getattr__(self, someattribute):
-        self.x += 1
-        if self.x > 1:
-            del self.attr
-        raise AttributeError
-
-def test_boom2_new():
-    a = Boom2_New()
-    b = Boom2_New()
-    a.attr = b
-    b.attr = a
-
-    gc.collect()
-    garbagelen = len(gc.garbage)
-    del a, b
-    expect(gc.collect(), 4, "boom2_new")
-    expect(len(gc.garbage), garbagelen, "boom2_new")
-
-def test_get_referents():
-    alist = [1, 3, 5]
-    got = gc.get_referents(alist)
-    got.sort()
-    expect(got, alist, "get_referents")
-
-    atuple = tuple(alist)
-    got = gc.get_referents(atuple)
-    got.sort()
-    expect(got, alist, "get_referents")
-
-    adict = {1: 3, 5: 7}
-    expected = [1, 3, 5, 7]
-    got = gc.get_referents(adict)
-    got.sort()
-    expect(got, expected, "get_referents")
-
-    got = gc.get_referents([1, 2], {3: 4}, (0, 0, 0))
-    got.sort()
-    expect(got, [0, 0] + range(5), "get_referents")
-
-    expect(gc.get_referents(1, 'a', 4j), [], "get_referents")
-
+### Support code
+###############################################################################
+        
 # Bug 1055820 has several tests of longstanding bugs involving weakrefs and
 # cyclic gc.
 
@@ -410,217 +31,556 @@
         # gc collects it.
         self.wr = weakref.ref(C1055820(666), it_happened)
 
-def test_bug1055820b():
-    # Corresponds to temp2b.py in the bug report.
 
-    ouch = []
-    def callback(ignored):
-        ouch[:] = [wr() for wr in WRs]
+### Tests        
+###############################################################################
+        
+class GCTests(unittest.TestCase):
+    def test_list(self):
+        l = []
+        l.append(l)
+        gc.collect()
+        del l
+        self.assertEqual(gc.collect(), 1)
 
-    Cs = [C1055820(i) for i in range(2)]
-    WRs = [weakref.ref(c, callback) for c in Cs]
-    c = None
+    def test_dict(self):
+        d = {}
+        d[1] = d
+        gc.collect()
+        del d
+        self.assertEqual(gc.collect(), 1)
 
-    gc.collect()
-    expect(len(ouch), 0, "bug1055820b")
-    # Make the two instances trash, and collect again.  The bug was that
-    # the callback materialized a strong reference to an instance, but gc
-    # cleared the instance's dict anyway.
-    Cs = None
-    gc.collect()
-    expect(len(ouch), 2, "bug1055820b")  # else the callbacks didn't run
-    for x in ouch:
-        # If the callback resurrected one of these guys, the instance
-        # would be damaged, with an empty __dict__.
-        expect(x, None, "bug1055820b")
+    def test_tuple(self):
+        # since tuples are immutable we close the loop with a list
+        l = []
+        t = (l,)
+        l.append(t)
+        gc.collect()
+        del t
+        del l
+        self.assertEqual(gc.collect(), 2)
 
-def test_bug1055820c():
-    # Corresponds to temp2c.py in the bug report.  This is pretty elaborate.
+    def test_class(self):
+        class A:
+            pass
+        A.a = A
+        gc.collect()
+        del A
+        self.assertNotEqual(gc.collect(), 0)
 
-    c0 = C1055820(0)
-    # Move c0 into generation 2.
-    gc.collect()
+    def test_newstyleclass(self):
+        class A(object):
+            pass
+        gc.collect()
+        del A
+        self.assertNotEqual(gc.collect(), 0)
 
-    c1 = C1055820(1)
-    c1.keep_c0_alive = c0
-    del c0.loop # now only c1 keeps c0 alive
+    def test_instance(self):
+        class A:
+            pass
+        a = A()
+        a.a = a
+        gc.collect()
+        del a
+        self.assertNotEqual(gc.collect(), 0)
 
-    c2 = C1055820(2)
-    c2wr = weakref.ref(c2) # no callback!
+    def test_newinstance(self):
+        class A(object):
+            pass
+        a = A()
+        a.a = a
+        gc.collect()
+        del a
+        self.assertNotEqual(gc.collect(), 0)
+        class B(list):
+            pass
+        class C(B, A):
+            pass
+        a = C()
+        a.a = a
+        gc.collect()
+        del a
+        self.assertNotEqual(gc.collect(), 0)
+        del B, C
+        self.assertNotEqual(gc.collect(), 0)
+        A.a = A()
+        del A
+        self.assertNotEqual(gc.collect(), 0)
+        self.assertEqual(gc.collect(), 0)
 
-    ouch = []
-    def callback(ignored):
-        ouch[:] = [c2wr()]
+    def test_method(self):
+        # Tricky: self.__init__ is a bound method, it references the instance.
+        class A:
+            def __init__(self):
+                self.init = self.__init__
+        a = A()
+        gc.collect()
+        del a
+        self.assertNotEqual(gc.collect(), 0)
 
-    # The callback gets associated with a wr on an object in generation 2.
-    c0wr = weakref.ref(c0, callback)
+    def test_finalizer(self):
+        # A() is uncollectable if it is part of a cycle, make sure it shows up
+        # in gc.garbage.
+        class A:
+            def __del__(self): pass
+        class B:
+            pass
+        a = A()
+        a.a = a
+        id_a = id(a)
+        b = B()
+        b.b = b
+        gc.collect()
+        del a
+        del b
+        self.assertNotEqual(gc.collect(), 0)
+        for obj in gc.garbage:
+            if id(obj) == id_a:
+                del obj.a
+                break
+        else:
+            self.fail("didn't find obj in garbage (finalizer)")
+        gc.garbage.remove(obj)
 
-    c0 = c1 = c2 = None
+    def test_finalizer_newclass(self):
+        # A() is uncollectable if it is part of a cycle, make sure it shows up
+        # in gc.garbage.
+        class A(object):
+            def __del__(self): pass
+        class B(object):
+            pass
+        a = A()
+        a.a = a
+        id_a = id(a)
+        b = B()
+        b.b = b
+        gc.collect()
+        del a
+        del b
+        self.assertNotEqual(gc.collect(), 0)
+        for obj in gc.garbage:
+            if id(obj) == id_a:
+                del obj.a
+                break
+        else:
+            self.fail("didn't find obj in garbage (finalizer)")
+        gc.garbage.remove(obj)
 
-    # What we've set up:  c0, c1, and c2 are all trash now.  c0 is in
-    # generation 2.  The only thing keeping it alive is that c1 points to it.
-    # c1 and c2 are in generation 0, and are in self-loops.  There's a global
-    # weakref to c2 (c2wr), but that weakref has no callback.  There's also
-    # a global weakref to c0 (c0wr), and that does have a callback, and that
-    # callback references c2 via c2wr().
-    #
-    #               c0 has a wr with callback, which references c2wr
-    #               ^
-    #               |
-    #               |     Generation 2 above dots
-    #. . . . . . . .|. . . . . . . . . . . . . . . . . . . . . . . .
-    #               |     Generation 0 below dots
-    #               |
-    #               |
-    #            ^->c1   ^->c2 has a wr but no callback
-    #            |  |    |  |
-    #            <--v    <--v
-    #
-    # So this is the nightmare:  when generation 0 gets collected, we see that
-    # c2 has a callback-free weakref, and c1 doesn't even have a weakref.
-    # Collecting generation 0 doesn't see c0 at all, and c0 is the only object
-    # that has a weakref with a callback.  gc clears c1 and c2.  Clearing c1
-    # has the side effect of dropping the refcount on c0 to 0, so c0 goes
-    # away (despite that it's in an older generation) and c0's wr callback
-    # triggers.  That in turn materializes a reference to c2 via c2wr(), but
-    # c2 gets cleared anyway by gc.
+    def test_function(self):
+        # Tricky: f -> d -> f, code should call d.clear() after the exec to
+        # break the cycle.
+        d = {}
+        exec("def f(): pass\n") in d
+        gc.collect()
+        del d
+        self.assertEqual(gc.collect(), 2)
 
-    # We want to let gc happen "naturally", to preserve the distinction
-    # between generations.
-    junk = []
-    i = 0
-    detector = GC_Detector()
-    while not detector.gc_happened:
-        i += 1
-        if i > 10000:
-            raise TestFailed("gc didn't happen after 10000 iterations")
-        expect(len(ouch), 0, "bug1055820c")
-        junk.append([])  # this will eventually trigger gc
+    def test_frame(self):
+        def f():
+            frame = sys._getframe()
+        gc.collect()
+        f()
+        self.assertEqual(gc.collect(), 1)
 
-    expect(len(ouch), 1, "bug1055820c")  # else the callback wasn't invoked
-    for x in ouch:
-        # If the callback resurrected c2, the instance would be damaged,
-        # with an empty __dict__.
-        expect(x, None, "bug1055820c")
+    def test_saveall(self):
+        # Verify that cyclic garbage like lists show up in gc.garbage if the
+        # SAVEALL option is enabled.
 
-def test_bug1055820d():
-    # Corresponds to temp2d.py in the bug report.  This is very much like
-    # test_bug1055820c, but uses a __del__ method instead of a weakref
-    # callback to sneak in a resurrection of cyclic trash.
+        # First make sure we don't save away other stuff that just happens to
+        # be waiting for collection.
+        gc.collect()
+        # if this fails, someone else created immortal trash
+        self.assertEqual(gc.garbage, [])
 
-    ouch = []
-    class D(C1055820):
-        def __del__(self):
+        L = []
+        L.append(L)
+        id_L = id(L)
+
+        debug = gc.get_debug()
+        gc.set_debug(debug | gc.DEBUG_SAVEALL)
+        del L
+        gc.collect()
+        gc.set_debug(debug)
+
+        self.assertEqual(len(gc.garbage), 1)
+        obj = gc.garbage.pop()
+        self.assertEqual(id(obj), id_L)
+
+    def test_del(self):
+        # __del__ methods can trigger collection, make this to happen
+        thresholds = gc.get_threshold()
+        gc.enable()
+        gc.set_threshold(1)
+
+        class A:
+            def __del__(self):
+                dir(self)
+        a = A()
+        del a
+
+        gc.disable()
+        gc.set_threshold(*thresholds)
+
+    def test_del_newclass(self):
+        # __del__ methods can trigger collection, make this to happen
+        thresholds = gc.get_threshold()
+        gc.enable()
+        gc.set_threshold(1)
+
+        class A(object):
+            def __del__(self):
+                dir(self)
+        a = A()
+        del a
+
+        gc.disable()
+        gc.set_threshold(*thresholds)
+
+    def test_get_count(self):
+        gc.collect()
+        self.assertEqual(gc.get_count(), (0, 0, 0))
+        a = dict()
+        self.assertEqual(gc.get_count(), (1, 0, 0))
+
+    def test_collect_generations(self):
+        gc.collect()
+        a = dict()
+        gc.collect(0)
+        self.assertEqual(gc.get_count(), (0, 1, 0))
+        gc.collect(1)
+        self.assertEqual(gc.get_count(), (0, 0, 1))
+        gc.collect(2)
+        self.assertEqual(gc.get_count(), (0, 0, 0))
+
+    def test_trashcan(self):
+        class Ouch:
+            n = 0
+            def __del__(self):
+                Ouch.n = Ouch.n + 1
+                if Ouch.n % 17 == 0:
+                    gc.collect()
+    
+        # "trashcan" is a hack to prevent stack overflow when deallocating
+        # very deeply nested tuples etc.  It works in part by abusing the
+        # type pointer and refcount fields, and that can yield horrible
+        # problems when gc tries to traverse the structures.
+        # If this test fails (as it does in 2.0, 2.1 and 2.2), it will
+        # most likely die via segfault.
+
+        # Note:  In 2.3 the possibility for compiling without cyclic gc was
+        # removed, and that in turn allows the trashcan mechanism to work
+        # via much simpler means (e.g., it never abuses the type pointer or
+        # refcount fields anymore).  Since it's much less likely to cause a
+        # problem now, the various constants in this expensive (we force a lot
+        # of full collections) test are cut back from the 2.2 version.
+        gc.enable()
+        N = 150
+        for count in range(2):
+            t = []
+            for i in range(N):
+                t = [t, Ouch()]
+            u = []
+            for i in range(N):
+                u = [u, Ouch()]
+            v = {}
+            for i in range(N):
+                v = {1: v, 2: Ouch()}
+        gc.disable()
+
+    def test_boom(self):
+        class Boom:
+            def __getattr__(self, someattribute):
+                del self.attr
+                raise AttributeError
+    
+        a = Boom()
+        b = Boom()
+        a.attr = b
+        b.attr = a
+
+        gc.collect()
+        garbagelen = len(gc.garbage)
+        del a, b
+        # a<->b are in a trash cycle now.  Collection will invoke
+        # Boom.__getattr__ (to see whether a and b have __del__ methods), and
+        # __getattr__ deletes the internal "attr" attributes as a side effect.
+        # That causes the trash cycle to get reclaimed via refcounts falling to
+        # 0, thus mutating the trash graph as a side effect of merely asking
+        # whether __del__ exists.  This used to (before 2.3b1) crash Python.
+        # Now __getattr__ isn't called.
+        self.assertEqual(gc.collect(), 4)
+        self.assertEqual(len(gc.garbage), garbagelen)
+
+    def test_boom2(self):
+        class Boom2:
+            def __init__(self):
+                self.x = 0
+
+            def __getattr__(self, someattribute):
+                self.x += 1
+                if self.x > 1:
+                    del self.attr
+                raise AttributeError
+    
+        a = Boom2()
+        b = Boom2()
+        a.attr = b
+        b.attr = a
+
+        gc.collect()
+        garbagelen = len(gc.garbage)
+        del a, b
+        # Much like test_boom(), except that __getattr__ doesn't break the
+        # cycle until the second time gc checks for __del__.  As of 2.3b1,
+        # there isn't a second time, so this simply cleans up the trash cycle.
+        # We expect a, b, a.__dict__ and b.__dict__ (4 objects) to get
+        # reclaimed this way.
+        self.assertEqual(gc.collect(), 4)
+        self.assertEqual(len(gc.garbage), garbagelen)
+
+    def test_boom_new(self):
+        # boom__new and boom2_new are exactly like boom and boom2, except use
+        # new-style classes.
+
+        class Boom_New(object):
+            def __getattr__(self, someattribute):
+                del self.attr
+                raise AttributeError
+    
+        a = Boom_New()
+        b = Boom_New()
+        a.attr = b
+        b.attr = a
+
+        gc.collect()
+        garbagelen = len(gc.garbage)
+        del a, b
+        self.assertEqual(gc.collect(), 4)
+        self.assertEqual(len(gc.garbage), garbagelen)
+
+    def test_boom2_new(self):
+        class Boom2_New(object):
+            def __init__(self):
+                self.x = 0
+
+            def __getattr__(self, someattribute):
+                self.x += 1
+                if self.x > 1:
+                    del self.attr
+                raise AttributeError
+    
+        a = Boom2_New()
+        b = Boom2_New()
+        a.attr = b
+        b.attr = a
+
+        gc.collect()
+        garbagelen = len(gc.garbage)
+        del a, b
+        self.assertEqual(gc.collect(), 4)
+        self.assertEqual(len(gc.garbage), garbagelen)
+
+    def test_get_referents(self):
+        alist = [1, 3, 5]
+        got = gc.get_referents(alist)
+        got.sort()
+        self.assertEqual(got, alist)
+
+        atuple = tuple(alist)
+        got = gc.get_referents(atuple)
+        got.sort()
+        self.assertEqual(got, alist)
+
+        adict = {1: 3, 5: 7}
+        expected = [1, 3, 5, 7]
+        got = gc.get_referents(adict)
+        got.sort()
+        self.assertEqual(got, expected)
+
+        got = gc.get_referents([1, 2], {3: 4}, (0, 0, 0))
+        got.sort()
+        self.assertEqual(got, [0, 0] + range(5))
+
+        self.assertEqual(gc.get_referents(1, 'a', 4j), [])
+
+    def test_bug1055820b(self):
+        # Corresponds to temp2b.py in the bug report.
+
+        ouch = []
+        def callback(ignored):
+            ouch[:] = [wr() for wr in WRs]
+
+        Cs = [C1055820(i) for i in range(2)]
+        WRs = [weakref.ref(c, callback) for c in Cs]
+        c = None
+
+        gc.collect()
+        self.assertEqual(len(ouch), 0)
+        # Make the two instances trash, and collect again.  The bug was that
+        # the callback materialized a strong reference to an instance, but gc
+        # cleared the instance's dict anyway.
+        Cs = None
+        gc.collect()
+        self.assertEqual(len(ouch), 2)  # else the callbacks didn't run
+        for x in ouch:
+            # If the callback resurrected one of these guys, the instance
+            # would be damaged, with an empty __dict__.
+            self.assertEqual(x, None)
+
+class GCTogglingTests(unittest.TestCase):
+    def setUp(self):
+        gc.enable()
+        
+    def tearDown(self):
+        gc.disable()
+    
+    def test_bug1055820c(self):
+        # Corresponds to temp2c.py in the bug report.  This is pretty
+        # elaborate.
+
+        c0 = C1055820(0)
+        # Move c0 into generation 2.
+        gc.collect()
+
+        c1 = C1055820(1)
+        c1.keep_c0_alive = c0
+        del c0.loop # now only c1 keeps c0 alive
+
+        c2 = C1055820(2)
+        c2wr = weakref.ref(c2) # no callback!
+
+        ouch = []
+        def callback(ignored):
             ouch[:] = [c2wr()]
 
-    d0 = D(0)
-    # Move all the above into generation 2.
-    gc.collect()
+        # The callback gets associated with a wr on an object in generation 2.
+        c0wr = weakref.ref(c0, callback)
 
-    c1 = C1055820(1)
-    c1.keep_d0_alive = d0
-    del d0.loop # now only c1 keeps d0 alive
+        c0 = c1 = c2 = None
 
-    c2 = C1055820(2)
-    c2wr = weakref.ref(c2) # no callback!
+        # What we've set up:  c0, c1, and c2 are all trash now.  c0 is in
+        # generation 2.  The only thing keeping it alive is that c1 points to
+        # it. c1 and c2 are in generation 0, and are in self-loops.  There's a
+        # global weakref to c2 (c2wr), but that weakref has no callback.
+        # There's also a global weakref to c0 (c0wr), and that does have a
+        # callback, and that callback references c2 via c2wr().
+        #
+        #               c0 has a wr with callback, which references c2wr
+        #               ^
+        #               |
+        #               |     Generation 2 above dots
+        #. . . . . . . .|. . . . . . . . . . . . . . . . . . . . . . . .
+        #               |     Generation 0 below dots
+        #               |
+        #               |
+        #            ^->c1   ^->c2 has a wr but no callback
+        #            |  |    |  |
+        #            <--v    <--v
+        #
+        # So this is the nightmare:  when generation 0 gets collected, we see
+        # that c2 has a callback-free weakref, and c1 doesn't even have a
+        # weakref.  Collecting generation 0 doesn't see c0 at all, and c0 is
+        # the only object that has a weakref with a callback.  gc clears c1
+        # and c2.  Clearing c1 has the side effect of dropping the refcount on
+        # c0 to 0, so c0 goes away (despite that it's in an older generation)
+        # and c0's wr callback triggers.  That in turn materializes a reference
+        # to c2 via c2wr(), but c2 gets cleared anyway by gc.
 
-    d0 = c1 = c2 = None
+        # We want to let gc happen "naturally", to preserve the distinction
+        # between generations.
+        junk = []
+        i = 0
+        detector = GC_Detector()
+        while not detector.gc_happened:
+            i += 1
+            if i > 10000:
+                self.fail("gc didn't happen after 10000 iterations")
+            self.assertEqual(len(ouch), 0)
+            junk.append([])  # this will eventually trigger gc
 
-    # What we've set up:  d0, c1, and c2 are all trash now.  d0 is in
-    # generation 2.  The only thing keeping it alive is that c1 points to it.
-    # c1 and c2 are in generation 0, and are in self-loops.  There's a global
-    # weakref to c2 (c2wr), but that weakref has no callback.  There are no
-    # other weakrefs.
-    #
-    #               d0 has a __del__ method that references c2wr
-    #               ^
-    #               |
-    #               |     Generation 2 above dots
-    #. . . . . . . .|. . . . . . . . . . . . . . . . . . . . . . . .
-    #               |     Generation 0 below dots
-    #               |
-    #               |
-    #            ^->c1   ^->c2 has a wr but no callback
-    #            |  |    |  |
-    #            <--v    <--v
-    #
-    # So this is the nightmare:  when generation 0 gets collected, we see that
-    # c2 has a callback-free weakref, and c1 doesn't even have a weakref.
-    # Collecting generation 0 doesn't see d0 at all.  gc clears c1 and c2.
-    # Clearing c1 has the side effect of dropping the refcount on d0 to 0, so
-    # d0 goes away (despite that it's in an older generation) and d0's __del__
-    # triggers.  That in turn materializes a reference to c2 via c2wr(), but
-    # c2 gets cleared anyway by gc.
+        self.assertEqual(len(ouch), 1)  # else the callback wasn't invoked
+        for x in ouch:
+            # If the callback resurrected c2, the instance would be damaged,
+            # with an empty __dict__.
+            self.assertEqual(x, None)
 
-    # We want to let gc happen "naturally", to preserve the distinction
-    # between generations.
-    detector = GC_Detector()
-    junk = []
-    i = 0
-    while not detector.gc_happened:
-        i += 1
-        if i > 10000:
-            raise TestFailed("gc didn't happen after 10000 iterations")
-        expect(len(ouch), 0, "bug1055820d")
-        junk.append([])  # this will eventually trigger gc
+    def test_bug1055820d(self):
+        # Corresponds to temp2d.py in the bug report.  This is very much like
+        # test_bug1055820c, but uses a __del__ method instead of a weakref
+        # callback to sneak in a resurrection of cyclic trash.
 
-    expect(len(ouch), 1, "bug1055820d")  # else __del__ wasn't invoked
-    for x in ouch:
-        # If __del__ resurrected c2, the instance would be damaged, with an
-        # empty __dict__.
-        expect(x, None, "bug1055820d")
+        ouch = []
+        class D(C1055820):
+            def __del__(self):
+                ouch[:] = [c2wr()]
 
+        d0 = D(0)
+        # Move all the above into generation 2.
+        gc.collect()
 
-def test_all():
-    gc.collect() # Delete 2nd generation garbage
-    run_test("lists", test_list)
-    run_test("dicts", test_dict)
-    run_test("tuples", test_tuple)
-    run_test("classes", test_class)
-    run_test("new style classes", test_newstyleclass)
-    run_test("instances", test_instance)
-    run_test("new instances", test_newinstance)
-    run_test("methods", test_method)
-    run_test("functions", test_function)
-    run_test("frames", test_frame)
-    run_test("finalizers", test_finalizer)
-    run_test("finalizers (new class)", test_finalizer_newclass)
-    run_test("__del__", test_del)
-    run_test("__del__ (new class)", test_del_newclass)
-    run_test("get_count()", test_get_count)
-    run_test("collect(n)", test_collect_generations)
-    run_test("saveall", test_saveall)
-    run_test("trashcan", test_trashcan)
-    run_test("boom", test_boom)
-    run_test("boom2", test_boom2)
-    run_test("boom_new", test_boom_new)
-    run_test("boom2_new", test_boom2_new)
-    run_test("get_referents", test_get_referents)
-    run_test("bug1055820b", test_bug1055820b)
+        c1 = C1055820(1)
+        c1.keep_d0_alive = d0
+        del d0.loop # now only c1 keeps d0 alive
 
-    gc.enable()
-    try:
-        run_test("bug1055820c", test_bug1055820c)
-    finally:
-        gc.disable()
+        c2 = C1055820(2)
+        c2wr = weakref.ref(c2) # no callback!
 
-    gc.enable()
-    try:
-        run_test("bug1055820d", test_bug1055820d)
-    finally:
-        gc.disable()
+        d0 = c1 = c2 = None
 
-def test():
-    if verbose:
-        print "disabling automatic collection"
+        # What we've set up:  d0, c1, and c2 are all trash now.  d0 is in
+        # generation 2.  The only thing keeping it alive is that c1 points to
+        # it.  c1 and c2 are in generation 0, and are in self-loops.  There's
+        # a global weakref to c2 (c2wr), but that weakref has no callback.
+        # There are no other weakrefs.
+        #
+        #               d0 has a __del__ method that references c2wr
+        #               ^
+        #               |
+        #               |     Generation 2 above dots
+        #. . . . . . . .|. . . . . . . . . . . . . . . . . . . . . . . .
+        #               |     Generation 0 below dots
+        #               |
+        #               |
+        #            ^->c1   ^->c2 has a wr but no callback
+        #            |  |    |  |
+        #            <--v    <--v
+        #
+        # So this is the nightmare:  when generation 0 gets collected, we see
+        # that c2 has a callback-free weakref, and c1 doesn't even have a
+        # weakref.  Collecting generation 0 doesn't see d0 at all.  gc clears
+        # c1 and c2.  Clearing c1 has the side effect of dropping the refcount
+        # on d0 to 0, so d0 goes away (despite that it's in an older
+        # generation) and d0's __del__ triggers.  That in turn materializes
+        # a reference to c2 via c2wr(), but c2 gets cleared anyway by gc.
+
+        # We want to let gc happen "naturally", to preserve the distinction
+        # between generations.
+        detector = GC_Detector()
+        junk = []
+        i = 0
+        while not detector.gc_happened:
+            i += 1
+            if i > 10000:
+                self.fail("gc didn't happen after 10000 iterations")
+            self.assertEqual(len(ouch), 0)
+            junk.append([])  # this will eventually trigger gc
+
+        self.assertEqual(len(ouch), 1)  # else __del__ wasn't invoked
+        for x in ouch:
+            # If __del__ resurrected c2, the instance would be damaged, with an
+            # empty __dict__.
+            self.assertEqual(x, None)
+
+def test_main():
     enabled = gc.isenabled()
     gc.disable()
-    verify(not gc.isenabled())
+    assert not gc.isenabled()
     debug = gc.get_debug()
     gc.set_debug(debug & ~gc.DEBUG_LEAK) # this test is supposed to leak
 
     try:
-        test_all()
+        gc.collect() # Delete 2nd generation garbage
+        run_unittest(GCTests, GCTogglingTests)
     finally:
         gc.set_debug(debug)
         # test gc.enable() even if GC is disabled by default
@@ -628,9 +588,9 @@
             print "restoring automatic collection"
         # make sure to always test gc.enable()
         gc.enable()
-        verify(gc.isenabled())
+        assert gc.isenabled()
         if not enabled:
             gc.disable()
-
-
-test()
+    
+if __name__ == "__main__":
+    test_main()