1import collections
2import collections.abc
3import gc
4import pickle
5import random
6import string
7import sys
8import unittest
9import weakref
10from test import support
11from test.support import import_helper
12
13
14class DictTest(unittest.TestCase):
15
16    def test_invalid_keyword_arguments(self):
17        class Custom(dict):
18            pass
19        for invalid in {1 : 2}, Custom({1 : 2}):
20            with self.assertRaises(TypeError):
21                dict(**invalid)
22            with self.assertRaises(TypeError):
23                {}.update(**invalid)
24
25    def test_constructor(self):
26        # calling built-in types without argument must return empty
27        self.assertEqual(dict(), {})
28        self.assertIsNot(dict(), {})
29
30    def test_literal_constructor(self):
31        # check literal constructor for different sized dicts
32        # (to exercise the BUILD_MAP oparg).
33        for n in (0, 1, 6, 256, 400):
34            items = [(''.join(random.sample(string.ascii_letters, 8)), i)
35                     for i in range(n)]
36            random.shuffle(items)
37            formatted_items = ('{!r}: {:d}'.format(k, v) for k, v in items)
38            dictliteral = '{' + ', '.join(formatted_items) + '}'
39            self.assertEqual(eval(dictliteral), dict(items))
40
41    def test_merge_operator(self):
42
43        a = {0: 0, 1: 1, 2: 1}
44        b = {1: 1, 2: 2, 3: 3}
45
46        c = a.copy()
47        c |= b
48
49        self.assertEqual(a | b, {0: 0, 1: 1, 2: 2, 3: 3})
50        self.assertEqual(c, {0: 0, 1: 1, 2: 2, 3: 3})
51
52        c = b.copy()
53        c |= a
54
55        self.assertEqual(b | a, {1: 1, 2: 1, 3: 3, 0: 0})
56        self.assertEqual(c, {1: 1, 2: 1, 3: 3, 0: 0})
57
58        c = a.copy()
59        c |= [(1, 1), (2, 2), (3, 3)]
60
61        self.assertEqual(c, {0: 0, 1: 1, 2: 2, 3: 3})
62
63        self.assertIs(a.__or__(None), NotImplemented)
64        self.assertIs(a.__or__(()), NotImplemented)
65        self.assertIs(a.__or__("BAD"), NotImplemented)
66        self.assertIs(a.__or__(""), NotImplemented)
67
68        self.assertRaises(TypeError, a.__ior__, None)
69        self.assertEqual(a.__ior__(()), {0: 0, 1: 1, 2: 1})
70        self.assertRaises(ValueError, a.__ior__, "BAD")
71        self.assertEqual(a.__ior__(""), {0: 0, 1: 1, 2: 1})
72
73    def test_bool(self):
74        self.assertIs(not {}, True)
75        self.assertTrue({1: 2})
76        self.assertIs(bool({}), False)
77        self.assertIs(bool({1: 2}), True)
78
79    def test_keys(self):
80        d = {}
81        self.assertEqual(set(d.keys()), set())
82        d = {'a': 1, 'b': 2}
83        k = d.keys()
84        self.assertEqual(set(k), {'a', 'b'})
85        self.assertIn('a', k)
86        self.assertIn('b', k)
87        self.assertIn('a', d)
88        self.assertIn('b', d)
89        self.assertRaises(TypeError, d.keys, None)
90        self.assertEqual(repr(dict(a=1).keys()), "dict_keys(['a'])")
91
92    def test_values(self):
93        d = {}
94        self.assertEqual(set(d.values()), set())
95        d = {1:2}
96        self.assertEqual(set(d.values()), {2})
97        self.assertRaises(TypeError, d.values, None)
98        self.assertEqual(repr(dict(a=1).values()), "dict_values([1])")
99
100    def test_items(self):
101        d = {}
102        self.assertEqual(set(d.items()), set())
103
104        d = {1:2}
105        self.assertEqual(set(d.items()), {(1, 2)})
106        self.assertRaises(TypeError, d.items, None)
107        self.assertEqual(repr(dict(a=1).items()), "dict_items([('a', 1)])")
108
109    def test_views_mapping(self):
110        mappingproxy = type(type.__dict__)
111        class Dict(dict):
112            pass
113        for cls in [dict, Dict]:
114            d = cls()
115            m1 = d.keys().mapping
116            m2 = d.values().mapping
117            m3 = d.items().mapping
118
119            for m in [m1, m2, m3]:
120                self.assertIsInstance(m, mappingproxy)
121                self.assertEqual(m, d)
122
123            d["foo"] = "bar"
124
125            for m in [m1, m2, m3]:
126                self.assertIsInstance(m, mappingproxy)
127                self.assertEqual(m, d)
128
129    def test_contains(self):
130        d = {}
131        self.assertNotIn('a', d)
132        self.assertFalse('a' in d)
133        self.assertTrue('a' not in d)
134        d = {'a': 1, 'b': 2}
135        self.assertIn('a', d)
136        self.assertIn('b', d)
137        self.assertNotIn('c', d)
138
139        self.assertRaises(TypeError, d.__contains__)
140
141    def test_len(self):
142        d = {}
143        self.assertEqual(len(d), 0)
144        d = {'a': 1, 'b': 2}
145        self.assertEqual(len(d), 2)
146
147    def test_getitem(self):
148        d = {'a': 1, 'b': 2}
149        self.assertEqual(d['a'], 1)
150        self.assertEqual(d['b'], 2)
151        d['c'] = 3
152        d['a'] = 4
153        self.assertEqual(d['c'], 3)
154        self.assertEqual(d['a'], 4)
155        del d['b']
156        self.assertEqual(d, {'a': 4, 'c': 3})
157
158        self.assertRaises(TypeError, d.__getitem__)
159
160        class BadEq(object):
161            def __eq__(self, other):
162                raise Exc()
163            def __hash__(self):
164                return 24
165
166        d = {}
167        d[BadEq()] = 42
168        self.assertRaises(KeyError, d.__getitem__, 23)
169
170        class Exc(Exception): pass
171
172        class BadHash(object):
173            fail = False
174            def __hash__(self):
175                if self.fail:
176                    raise Exc()
177                else:
178                    return 42
179
180        x = BadHash()
181        d[x] = 42
182        x.fail = True
183        self.assertRaises(Exc, d.__getitem__, x)
184
185    def test_clear(self):
186        d = {1:1, 2:2, 3:3}
187        d.clear()
188        self.assertEqual(d, {})
189
190        self.assertRaises(TypeError, d.clear, None)
191
192    def test_update(self):
193        d = {}
194        d.update({1:100})
195        d.update({2:20})
196        d.update({1:1, 2:2, 3:3})
197        self.assertEqual(d, {1:1, 2:2, 3:3})
198
199        d.update()
200        self.assertEqual(d, {1:1, 2:2, 3:3})
201
202        self.assertRaises((TypeError, AttributeError), d.update, None)
203
204        class SimpleUserDict:
205            def __init__(self):
206                self.d = {1:1, 2:2, 3:3}
207            def keys(self):
208                return self.d.keys()
209            def __getitem__(self, i):
210                return self.d[i]
211        d.clear()
212        d.update(SimpleUserDict())
213        self.assertEqual(d, {1:1, 2:2, 3:3})
214
215        class Exc(Exception): pass
216
217        d.clear()
218        class FailingUserDict:
219            def keys(self):
220                raise Exc
221        self.assertRaises(Exc, d.update, FailingUserDict())
222
223        class FailingUserDict:
224            def keys(self):
225                class BogonIter:
226                    def __init__(self):
227                        self.i = 1
228                    def __iter__(self):
229                        return self
230                    def __next__(self):
231                        if self.i:
232                            self.i = 0
233                            return 'a'
234                        raise Exc
235                return BogonIter()
236            def __getitem__(self, key):
237                return key
238        self.assertRaises(Exc, d.update, FailingUserDict())
239
240        class FailingUserDict:
241            def keys(self):
242                class BogonIter:
243                    def __init__(self):
244                        self.i = ord('a')
245                    def __iter__(self):
246                        return self
247                    def __next__(self):
248                        if self.i <= ord('z'):
249                            rtn = chr(self.i)
250                            self.i += 1
251                            return rtn
252                        raise StopIteration
253                return BogonIter()
254            def __getitem__(self, key):
255                raise Exc
256        self.assertRaises(Exc, d.update, FailingUserDict())
257
258        class badseq(object):
259            def __iter__(self):
260                return self
261            def __next__(self):
262                raise Exc()
263
264        self.assertRaises(Exc, {}.update, badseq())
265
266        self.assertRaises(ValueError, {}.update, [(1, 2, 3)])
267
268    def test_fromkeys(self):
269        self.assertEqual(dict.fromkeys('abc'), {'a':None, 'b':None, 'c':None})
270        d = {}
271        self.assertIsNot(d.fromkeys('abc'), d)
272        self.assertEqual(d.fromkeys('abc'), {'a':None, 'b':None, 'c':None})
273        self.assertEqual(d.fromkeys((4,5),0), {4:0, 5:0})
274        self.assertEqual(d.fromkeys([]), {})
275        def g():
276            yield 1
277        self.assertEqual(d.fromkeys(g()), {1:None})
278        self.assertRaises(TypeError, {}.fromkeys, 3)
279        class dictlike(dict): pass
280        self.assertEqual(dictlike.fromkeys('a'), {'a':None})
281        self.assertEqual(dictlike().fromkeys('a'), {'a':None})
282        self.assertIsInstance(dictlike.fromkeys('a'), dictlike)
283        self.assertIsInstance(dictlike().fromkeys('a'), dictlike)
284        class mydict(dict):
285            def __new__(cls):
286                return collections.UserDict()
287        ud = mydict.fromkeys('ab')
288        self.assertEqual(ud, {'a':None, 'b':None})
289        self.assertIsInstance(ud, collections.UserDict)
290        self.assertRaises(TypeError, dict.fromkeys)
291
292        class Exc(Exception): pass
293
294        class baddict1(dict):
295            def __init__(self):
296                raise Exc()
297
298        self.assertRaises(Exc, baddict1.fromkeys, [1])
299
300        class BadSeq(object):
301            def __iter__(self):
302                return self
303            def __next__(self):
304                raise Exc()
305
306        self.assertRaises(Exc, dict.fromkeys, BadSeq())
307
308        class baddict2(dict):
309            def __setitem__(self, key, value):
310                raise Exc()
311
312        self.assertRaises(Exc, baddict2.fromkeys, [1])
313
314        # test fast path for dictionary inputs
315        d = dict(zip(range(6), range(6)))
316        self.assertEqual(dict.fromkeys(d, 0), dict(zip(range(6), [0]*6)))
317
318        class baddict3(dict):
319            def __new__(cls):
320                return d
321        d = {i : i for i in range(10)}
322        res = d.copy()
323        res.update(a=None, b=None, c=None)
324        self.assertEqual(baddict3.fromkeys({"a", "b", "c"}), res)
325
326    def test_copy(self):
327        d = {1: 1, 2: 2, 3: 3}
328        self.assertIsNot(d.copy(), d)
329        self.assertEqual(d.copy(), d)
330        self.assertEqual(d.copy(), {1: 1, 2: 2, 3: 3})
331
332        copy = d.copy()
333        d[4] = 4
334        self.assertNotEqual(copy, d)
335
336        self.assertEqual({}.copy(), {})
337        self.assertRaises(TypeError, d.copy, None)
338
339    def test_copy_fuzz(self):
340        for dict_size in [10, 100, 1000, 10000, 100000]:
341            dict_size = random.randrange(
342                dict_size // 2, dict_size + dict_size // 2)
343            with self.subTest(dict_size=dict_size):
344                d = {}
345                for i in range(dict_size):
346                    d[i] = i
347
348                d2 = d.copy()
349                self.assertIsNot(d2, d)
350                self.assertEqual(d, d2)
351                d2['key'] = 'value'
352                self.assertNotEqual(d, d2)
353                self.assertEqual(len(d2), len(d) + 1)
354
355    def test_copy_maintains_tracking(self):
356        class A:
357            pass
358
359        key = A()
360
361        for d in ({}, {'a': 1}, {key: 'val'}):
362            d2 = d.copy()
363            self.assertEqual(gc.is_tracked(d), gc.is_tracked(d2))
364
365    def test_copy_noncompact(self):
366        # Dicts don't compact themselves on del/pop operations.
367        # Copy will use a slow merging strategy that produces
368        # a compacted copy when roughly 33% of dict is a non-used
369        # keys-space (to optimize memory footprint).
370        # In this test we want to hit the slow/compacting
371        # branch of dict.copy() and make sure it works OK.
372        d = {k: k for k in range(1000)}
373        for k in range(950):
374            del d[k]
375        d2 = d.copy()
376        self.assertEqual(d2, d)
377
378    def test_get(self):
379        d = {}
380        self.assertIs(d.get('c'), None)
381        self.assertEqual(d.get('c', 3), 3)
382        d = {'a': 1, 'b': 2}
383        self.assertIs(d.get('c'), None)
384        self.assertEqual(d.get('c', 3), 3)
385        self.assertEqual(d.get('a'), 1)
386        self.assertEqual(d.get('a', 3), 1)
387        self.assertRaises(TypeError, d.get)
388        self.assertRaises(TypeError, d.get, None, None, None)
389
390    def test_setdefault(self):
391        # dict.setdefault()
392        d = {}
393        self.assertIs(d.setdefault('key0'), None)
394        d.setdefault('key0', [])
395        self.assertIs(d.setdefault('key0'), None)
396        d.setdefault('key', []).append(3)
397        self.assertEqual(d['key'][0], 3)
398        d.setdefault('key', []).append(4)
399        self.assertEqual(len(d['key']), 2)
400        self.assertRaises(TypeError, d.setdefault)
401
402        class Exc(Exception): pass
403
404        class BadHash(object):
405            fail = False
406            def __hash__(self):
407                if self.fail:
408                    raise Exc()
409                else:
410                    return 42
411
412        x = BadHash()
413        d[x] = 42
414        x.fail = True
415        self.assertRaises(Exc, d.setdefault, x, [])
416
417    def test_setdefault_atomic(self):
418        # Issue #13521: setdefault() calls __hash__ and __eq__ only once.
419        class Hashed(object):
420            def __init__(self):
421                self.hash_count = 0
422                self.eq_count = 0
423            def __hash__(self):
424                self.hash_count += 1
425                return 42
426            def __eq__(self, other):
427                self.eq_count += 1
428                return id(self) == id(other)
429        hashed1 = Hashed()
430        y = {hashed1: 5}
431        hashed2 = Hashed()
432        y.setdefault(hashed2, [])
433        self.assertEqual(hashed1.hash_count, 1)
434        self.assertEqual(hashed2.hash_count, 1)
435        self.assertEqual(hashed1.eq_count + hashed2.eq_count, 1)
436
437    def test_setitem_atomic_at_resize(self):
438        class Hashed(object):
439            def __init__(self):
440                self.hash_count = 0
441                self.eq_count = 0
442            def __hash__(self):
443                self.hash_count += 1
444                return 42
445            def __eq__(self, other):
446                self.eq_count += 1
447                return id(self) == id(other)
448        hashed1 = Hashed()
449        # 5 items
450        y = {hashed1: 5, 0: 0, 1: 1, 2: 2, 3: 3}
451        hashed2 = Hashed()
452        # 6th item forces a resize
453        y[hashed2] = []
454        self.assertEqual(hashed1.hash_count, 1)
455        self.assertEqual(hashed2.hash_count, 1)
456        self.assertEqual(hashed1.eq_count + hashed2.eq_count, 1)
457
458    def test_popitem(self):
459        # dict.popitem()
460        for copymode in -1, +1:
461            # -1: b has same structure as a
462            # +1: b is a.copy()
463            for log2size in range(12):
464                size = 2**log2size
465                a = {}
466                b = {}
467                for i in range(size):
468                    a[repr(i)] = i
469                    if copymode < 0:
470                        b[repr(i)] = i
471                if copymode > 0:
472                    b = a.copy()
473                for i in range(size):
474                    ka, va = ta = a.popitem()
475                    self.assertEqual(va, int(ka))
476                    kb, vb = tb = b.popitem()
477                    self.assertEqual(vb, int(kb))
478                    self.assertFalse(copymode < 0 and ta != tb)
479                self.assertFalse(a)
480                self.assertFalse(b)
481
482        d = {}
483        self.assertRaises(KeyError, d.popitem)
484
485    def test_pop(self):
486        # Tests for pop with specified key
487        d = {}
488        k, v = 'abc', 'def'
489        d[k] = v
490        self.assertRaises(KeyError, d.pop, 'ghi')
491
492        self.assertEqual(d.pop(k), v)
493        self.assertEqual(len(d), 0)
494
495        self.assertRaises(KeyError, d.pop, k)
496
497        self.assertEqual(d.pop(k, v), v)
498        d[k] = v
499        self.assertEqual(d.pop(k, 1), v)
500
501        self.assertRaises(TypeError, d.pop)
502
503        class Exc(Exception): pass
504
505        class BadHash(object):
506            fail = False
507            def __hash__(self):
508                if self.fail:
509                    raise Exc()
510                else:
511                    return 42
512
513        x = BadHash()
514        d[x] = 42
515        x.fail = True
516        self.assertRaises(Exc, d.pop, x)
517
518    def test_mutating_iteration(self):
519        # changing dict size during iteration
520        d = {}
521        d[1] = 1
522        with self.assertRaises(RuntimeError):
523            for i in d:
524                d[i+1] = 1
525
526    def test_mutating_iteration_delete(self):
527        # change dict content during iteration
528        d = {}
529        d[0] = 0
530        with self.assertRaises(RuntimeError):
531            for i in d:
532                del d[0]
533                d[0] = 0
534
535    def test_mutating_iteration_delete_over_values(self):
536        # change dict content during iteration
537        d = {}
538        d[0] = 0
539        with self.assertRaises(RuntimeError):
540            for i in d.values():
541                del d[0]
542                d[0] = 0
543
544    def test_mutating_iteration_delete_over_items(self):
545        # change dict content during iteration
546        d = {}
547        d[0] = 0
548        with self.assertRaises(RuntimeError):
549            for i in d.items():
550                del d[0]
551                d[0] = 0
552
553    def test_mutating_lookup(self):
554        # changing dict during a lookup (issue #14417)
555        class NastyKey:
556            mutate_dict = None
557
558            def __init__(self, value):
559                self.value = value
560
561            def __hash__(self):
562                # hash collision!
563                return 1
564
565            def __eq__(self, other):
566                if NastyKey.mutate_dict:
567                    mydict, key = NastyKey.mutate_dict
568                    NastyKey.mutate_dict = None
569                    del mydict[key]
570                return self.value == other.value
571
572        key1 = NastyKey(1)
573        key2 = NastyKey(2)
574        d = {key1: 1}
575        NastyKey.mutate_dict = (d, key1)
576        d[key2] = 2
577        self.assertEqual(d, {key2: 2})
578
579    def test_repr(self):
580        d = {}
581        self.assertEqual(repr(d), '{}')
582        d[1] = 2
583        self.assertEqual(repr(d), '{1: 2}')
584        d = {}
585        d[1] = d
586        self.assertEqual(repr(d), '{1: {...}}')
587
588        class Exc(Exception): pass
589
590        class BadRepr(object):
591            def __repr__(self):
592                raise Exc()
593
594        d = {1: BadRepr()}
595        self.assertRaises(Exc, repr, d)
596
597    def test_repr_deep(self):
598        d = {}
599        for i in range(sys.getrecursionlimit() + 100):
600            d = {1: d}
601        self.assertRaises(RecursionError, repr, d)
602
603    def test_eq(self):
604        self.assertEqual({}, {})
605        self.assertEqual({1: 2}, {1: 2})
606
607        class Exc(Exception): pass
608
609        class BadCmp(object):
610            def __eq__(self, other):
611                raise Exc()
612            def __hash__(self):
613                return 1
614
615        d1 = {BadCmp(): 1}
616        d2 = {1: 1}
617
618        with self.assertRaises(Exc):
619            d1 == d2
620
621    def test_keys_contained(self):
622        self.helper_keys_contained(lambda x: x.keys())
623        self.helper_keys_contained(lambda x: x.items())
624
625    def helper_keys_contained(self, fn):
626        # Test rich comparisons against dict key views, which should behave the
627        # same as sets.
628        empty = fn(dict())
629        empty2 = fn(dict())
630        smaller = fn({1:1, 2:2})
631        larger = fn({1:1, 2:2, 3:3})
632        larger2 = fn({1:1, 2:2, 3:3})
633        larger3 = fn({4:1, 2:2, 3:3})
634
635        self.assertTrue(smaller <  larger)
636        self.assertTrue(smaller <= larger)
637        self.assertTrue(larger >  smaller)
638        self.assertTrue(larger >= smaller)
639
640        self.assertFalse(smaller >= larger)
641        self.assertFalse(smaller >  larger)
642        self.assertFalse(larger  <= smaller)
643        self.assertFalse(larger  <  smaller)
644
645        self.assertFalse(smaller <  larger3)
646        self.assertFalse(smaller <= larger3)
647        self.assertFalse(larger3 >  smaller)
648        self.assertFalse(larger3 >= smaller)
649
650        # Inequality strictness
651        self.assertTrue(larger2 >= larger)
652        self.assertTrue(larger2 <= larger)
653        self.assertFalse(larger2 > larger)
654        self.assertFalse(larger2 < larger)
655
656        self.assertTrue(larger == larger2)
657        self.assertTrue(smaller != larger)
658
659        # There is an optimization on the zero-element case.
660        self.assertTrue(empty == empty2)
661        self.assertFalse(empty != empty2)
662        self.assertFalse(empty == smaller)
663        self.assertTrue(empty != smaller)
664
665        # With the same size, an elementwise compare happens
666        self.assertTrue(larger != larger3)
667        self.assertFalse(larger == larger3)
668
669    def test_errors_in_view_containment_check(self):
670        class C:
671            def __eq__(self, other):
672                raise RuntimeError
673
674        d1 = {1: C()}
675        d2 = {1: C()}
676        with self.assertRaises(RuntimeError):
677            d1.items() == d2.items()
678        with self.assertRaises(RuntimeError):
679            d1.items() != d2.items()
680        with self.assertRaises(RuntimeError):
681            d1.items() <= d2.items()
682        with self.assertRaises(RuntimeError):
683            d1.items() >= d2.items()
684
685        d3 = {1: C(), 2: C()}
686        with self.assertRaises(RuntimeError):
687            d2.items() < d3.items()
688        with self.assertRaises(RuntimeError):
689            d3.items() > d2.items()
690
691    def test_dictview_set_operations_on_keys(self):
692        k1 = {1:1, 2:2}.keys()
693        k2 = {1:1, 2:2, 3:3}.keys()
694        k3 = {4:4}.keys()
695
696        self.assertEqual(k1 - k2, set())
697        self.assertEqual(k1 - k3, {1,2})
698        self.assertEqual(k2 - k1, {3})
699        self.assertEqual(k3 - k1, {4})
700        self.assertEqual(k1 & k2, {1,2})
701        self.assertEqual(k1 & k3, set())
702        self.assertEqual(k1 | k2, {1,2,3})
703        self.assertEqual(k1 ^ k2, {3})
704        self.assertEqual(k1 ^ k3, {1,2,4})
705
706    def test_dictview_set_operations_on_items(self):
707        k1 = {1:1, 2:2}.items()
708        k2 = {1:1, 2:2, 3:3}.items()
709        k3 = {4:4}.items()
710
711        self.assertEqual(k1 - k2, set())
712        self.assertEqual(k1 - k3, {(1,1), (2,2)})
713        self.assertEqual(k2 - k1, {(3,3)})
714        self.assertEqual(k3 - k1, {(4,4)})
715        self.assertEqual(k1 & k2, {(1,1), (2,2)})
716        self.assertEqual(k1 & k3, set())
717        self.assertEqual(k1 | k2, {(1,1), (2,2), (3,3)})
718        self.assertEqual(k1 ^ k2, {(3,3)})
719        self.assertEqual(k1 ^ k3, {(1,1), (2,2), (4,4)})
720
721    def test_items_symmetric_difference(self):
722        rr = random.randrange
723        for _ in range(100):
724            left = {x:rr(3) for x in range(20) if rr(2)}
725            right = {x:rr(3) for x in range(20) if rr(2)}
726            with self.subTest(left=left, right=right):
727                expected = set(left.items()) ^ set(right.items())
728                actual = left.items() ^ right.items()
729                self.assertEqual(actual, expected)
730
731    def test_dictview_mixed_set_operations(self):
732        # Just a few for .keys()
733        self.assertTrue({1:1}.keys() == {1})
734        self.assertTrue({1} == {1:1}.keys())
735        self.assertEqual({1:1}.keys() | {2}, {1, 2})
736        self.assertEqual({2} | {1:1}.keys(), {1, 2})
737        # And a few for .items()
738        self.assertTrue({1:1}.items() == {(1,1)})
739        self.assertTrue({(1,1)} == {1:1}.items())
740        self.assertEqual({1:1}.items() | {2}, {(1,1), 2})
741        self.assertEqual({2} | {1:1}.items(), {(1,1), 2})
742
743    def test_missing(self):
744        # Make sure dict doesn't have a __missing__ method
745        self.assertFalse(hasattr(dict, "__missing__"))
746        self.assertFalse(hasattr({}, "__missing__"))
747        # Test several cases:
748        # (D) subclass defines __missing__ method returning a value
749        # (E) subclass defines __missing__ method raising RuntimeError
750        # (F) subclass sets __missing__ instance variable (no effect)
751        # (G) subclass doesn't define __missing__ at all
752        class D(dict):
753            def __missing__(self, key):
754                return 42
755        d = D({1: 2, 3: 4})
756        self.assertEqual(d[1], 2)
757        self.assertEqual(d[3], 4)
758        self.assertNotIn(2, d)
759        self.assertNotIn(2, d.keys())
760        self.assertEqual(d[2], 42)
761
762        class E(dict):
763            def __missing__(self, key):
764                raise RuntimeError(key)
765        e = E()
766        with self.assertRaises(RuntimeError) as c:
767            e[42]
768        self.assertEqual(c.exception.args, (42,))
769
770        class F(dict):
771            def __init__(self):
772                # An instance variable __missing__ should have no effect
773                self.__missing__ = lambda key: None
774        f = F()
775        with self.assertRaises(KeyError) as c:
776            f[42]
777        self.assertEqual(c.exception.args, (42,))
778
779        class G(dict):
780            pass
781        g = G()
782        with self.assertRaises(KeyError) as c:
783            g[42]
784        self.assertEqual(c.exception.args, (42,))
785
786    def test_tuple_keyerror(self):
787        # SF #1576657
788        d = {}
789        with self.assertRaises(KeyError) as c:
790            d[(1,)]
791        self.assertEqual(c.exception.args, ((1,),))
792
793    def test_bad_key(self):
794        # Dictionary lookups should fail if __eq__() raises an exception.
795        class CustomException(Exception):
796            pass
797
798        class BadDictKey:
799            def __hash__(self):
800                return hash(self.__class__)
801
802            def __eq__(self, other):
803                if isinstance(other, self.__class__):
804                    raise CustomException
805                return other
806
807        d = {}
808        x1 = BadDictKey()
809        x2 = BadDictKey()
810        d[x1] = 1
811        for stmt in ['d[x2] = 2',
812                     'z = d[x2]',
813                     'x2 in d',
814                     'd.get(x2)',
815                     'd.setdefault(x2, 42)',
816                     'd.pop(x2)',
817                     'd.update({x2: 2})']:
818            with self.assertRaises(CustomException):
819                exec(stmt, locals())
820
821    def test_resize1(self):
822        # Dict resizing bug, found by Jack Jansen in 2.2 CVS development.
823        # This version got an assert failure in debug build, infinite loop in
824        # release build.  Unfortunately, provoking this kind of stuff requires
825        # a mix of inserts and deletes hitting exactly the right hash codes in
826        # exactly the right order, and I can't think of a randomized approach
827        # that would be *likely* to hit a failing case in reasonable time.
828
829        d = {}
830        for i in range(5):
831            d[i] = i
832        for i in range(5):
833            del d[i]
834        for i in range(5, 9):  # i==8 was the problem
835            d[i] = i
836
837    def test_resize2(self):
838        # Another dict resizing bug (SF bug #1456209).
839        # This caused Segmentation faults or Illegal instructions.
840
841        class X(object):
842            def __hash__(self):
843                return 5
844            def __eq__(self, other):
845                if resizing:
846                    d.clear()
847                return False
848        d = {}
849        resizing = False
850        d[X()] = 1
851        d[X()] = 2
852        d[X()] = 3
853        d[X()] = 4
854        d[X()] = 5
855        # now trigger a resize
856        resizing = True
857        d[9] = 6
858
859    def test_empty_presized_dict_in_freelist(self):
860        # Bug #3537: if an empty but presized dict with a size larger
861        # than 7 was in the freelist, it triggered an assertion failure
862        with self.assertRaises(ZeroDivisionError):
863            d = {'a': 1 // 0, 'b': None, 'c': None, 'd': None, 'e': None,
864                 'f': None, 'g': None, 'h': None}
865        d = {}
866
867    def test_container_iterator(self):
868        # Bug #3680: tp_traverse was not implemented for dictiter and
869        # dictview objects.
870        class C(object):
871            pass
872        views = (dict.items, dict.values, dict.keys)
873        for v in views:
874            obj = C()
875            ref = weakref.ref(obj)
876            container = {obj: 1}
877            obj.v = v(container)
878            obj.x = iter(obj.v)
879            del obj, container
880            gc.collect()
881            self.assertIs(ref(), None, "Cycle was not collected")
882
883    def _not_tracked(self, t):
884        # Nested containers can take several collections to untrack
885        gc.collect()
886        gc.collect()
887        self.assertFalse(gc.is_tracked(t), t)
888
889    def _tracked(self, t):
890        self.assertTrue(gc.is_tracked(t), t)
891        gc.collect()
892        gc.collect()
893        self.assertTrue(gc.is_tracked(t), t)
894
895    def test_string_keys_can_track_values(self):
896        # Test that this doesn't leak.
897        for i in range(10):
898            d = {}
899            for j in range(10):
900                d[str(j)] = j
901            d["foo"] = d
902
903    @support.cpython_only
904    def test_track_literals(self):
905        # Test GC-optimization of dict literals
906        x, y, z, w = 1.5, "a", (1, None), []
907
908        self._not_tracked({})
909        self._not_tracked({x:(), y:x, z:1})
910        self._not_tracked({1: "a", "b": 2})
911        self._not_tracked({1: 2, (None, True, False, ()): int})
912        self._not_tracked({1: object()})
913
914        # Dicts with mutable elements are always tracked, even if those
915        # elements are not tracked right now.
916        self._tracked({1: []})
917        self._tracked({1: ([],)})
918        self._tracked({1: {}})
919        self._tracked({1: set()})
920
921    @support.cpython_only
922    def test_track_dynamic(self):
923        # Test GC-optimization of dynamically-created dicts
924        class MyObject(object):
925            pass
926        x, y, z, w, o = 1.5, "a", (1, object()), [], MyObject()
927
928        d = dict()
929        self._not_tracked(d)
930        d[1] = "a"
931        self._not_tracked(d)
932        d[y] = 2
933        self._not_tracked(d)
934        d[z] = 3
935        self._not_tracked(d)
936        self._not_tracked(d.copy())
937        d[4] = w
938        self._tracked(d)
939        self._tracked(d.copy())
940        d[4] = None
941        self._not_tracked(d)
942        self._not_tracked(d.copy())
943
944        # dd isn't tracked right now, but it may mutate and therefore d
945        # which contains it must be tracked.
946        d = dict()
947        dd = dict()
948        d[1] = dd
949        self._not_tracked(dd)
950        self._tracked(d)
951        dd[1] = d
952        self._tracked(dd)
953
954        d = dict.fromkeys([x, y, z])
955        self._not_tracked(d)
956        dd = dict()
957        dd.update(d)
958        self._not_tracked(dd)
959        d = dict.fromkeys([x, y, z, o])
960        self._tracked(d)
961        dd = dict()
962        dd.update(d)
963        self._tracked(dd)
964
965        d = dict(x=x, y=y, z=z)
966        self._not_tracked(d)
967        d = dict(x=x, y=y, z=z, w=w)
968        self._tracked(d)
969        d = dict()
970        d.update(x=x, y=y, z=z)
971        self._not_tracked(d)
972        d.update(w=w)
973        self._tracked(d)
974
975        d = dict([(x, y), (z, 1)])
976        self._not_tracked(d)
977        d = dict([(x, y), (z, w)])
978        self._tracked(d)
979        d = dict()
980        d.update([(x, y), (z, 1)])
981        self._not_tracked(d)
982        d.update([(x, y), (z, w)])
983        self._tracked(d)
984
985    @support.cpython_only
986    def test_track_subtypes(self):
987        # Dict subtypes are always tracked
988        class MyDict(dict):
989            pass
990        self._tracked(MyDict())
991
992    def make_shared_key_dict(self, n):
993        class C:
994            pass
995
996        dicts = []
997        for i in range(n):
998            a = C()
999            a.x, a.y, a.z = 1, 2, 3
1000            dicts.append(a.__dict__)
1001
1002        return dicts
1003
1004    @support.cpython_only
1005    def test_splittable_setdefault(self):
1006        """split table must keep correct insertion
1007        order when attributes are adding using setdefault()"""
1008        a, b = self.make_shared_key_dict(2)
1009
1010        a['a'] = 1
1011        size_a = sys.getsizeof(a)
1012        a['b'] = 2
1013        b.setdefault('b', 2)
1014        size_b = sys.getsizeof(b)
1015        b['a'] = 1
1016
1017        self.assertEqual(list(a), ['x', 'y', 'z', 'a', 'b'])
1018        self.assertEqual(list(b), ['x', 'y', 'z', 'b', 'a'])
1019
1020    @support.cpython_only
1021    def test_splittable_del(self):
1022        """split table must be combined when del d[k]"""
1023        a, b = self.make_shared_key_dict(2)
1024
1025        orig_size = sys.getsizeof(a)
1026
1027        del a['y']  # split table is combined
1028        with self.assertRaises(KeyError):
1029            del a['y']
1030
1031        self.assertEqual(list(a), ['x', 'z'])
1032        self.assertEqual(list(b), ['x', 'y', 'z'])
1033
1034        # Two dicts have different insertion order.
1035        a['y'] = 42
1036        self.assertEqual(list(a), ['x', 'z', 'y'])
1037        self.assertEqual(list(b), ['x', 'y', 'z'])
1038
1039    @support.cpython_only
1040    def test_splittable_pop(self):
1041        a, b = self.make_shared_key_dict(2)
1042
1043        a.pop('y')
1044        with self.assertRaises(KeyError):
1045            a.pop('y')
1046
1047        self.assertEqual(list(a), ['x', 'z'])
1048        self.assertEqual(list(b), ['x', 'y', 'z'])
1049
1050        # Two dicts have different insertion order.
1051        a['y'] = 42
1052        self.assertEqual(list(a), ['x', 'z', 'y'])
1053        self.assertEqual(list(b), ['x', 'y', 'z'])
1054
1055    @support.cpython_only
1056    def test_splittable_pop_pending(self):
1057        """pop a pending key in a split table should not crash"""
1058        a, b = self.make_shared_key_dict(2)
1059
1060        a['a'] = 4
1061        with self.assertRaises(KeyError):
1062            b.pop('a')
1063
1064    @support.cpython_only
1065    def test_splittable_popitem(self):
1066        """split table must be combined when d.popitem()"""
1067        a, b = self.make_shared_key_dict(2)
1068
1069        orig_size = sys.getsizeof(a)
1070
1071        item = a.popitem()  # split table is combined
1072        self.assertEqual(item, ('z', 3))
1073        with self.assertRaises(KeyError):
1074            del a['z']
1075
1076        self.assertGreater(sys.getsizeof(a), orig_size)
1077        self.assertEqual(list(a), ['x', 'y'])
1078        self.assertEqual(list(b), ['x', 'y', 'z'])
1079
1080    @support.cpython_only
1081    def test_splittable_update(self):
1082        """dict.update(other) must preserve order in other."""
1083        class C:
1084            def __init__(self, order):
1085                if order:
1086                    self.a, self.b, self.c = 1, 2, 3
1087                else:
1088                    self.c, self.b, self.a = 1, 2, 3
1089        o = C(True)
1090        o = C(False)  # o.__dict__ has reversed order.
1091        self.assertEqual(list(o.__dict__), ["c", "b", "a"])
1092
1093        d = {}
1094        d.update(o.__dict__)
1095        self.assertEqual(list(d), ["c", "b", "a"])
1096
1097    def test_iterator_pickling(self):
1098        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
1099            data = {1:"a", 2:"b", 3:"c"}
1100            it = iter(data)
1101            d = pickle.dumps(it, proto)
1102            it = pickle.loads(d)
1103            self.assertEqual(list(it), list(data))
1104
1105            it = pickle.loads(d)
1106            try:
1107                drop = next(it)
1108            except StopIteration:
1109                continue
1110            d = pickle.dumps(it, proto)
1111            it = pickle.loads(d)
1112            del data[drop]
1113            self.assertEqual(list(it), list(data))
1114
1115    def test_itemiterator_pickling(self):
1116        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
1117            data = {1:"a", 2:"b", 3:"c"}
1118            # dictviews aren't picklable, only their iterators
1119            itorg = iter(data.items())
1120            d = pickle.dumps(itorg, proto)
1121            it = pickle.loads(d)
1122            # note that the type of the unpickled iterator
1123            # is not necessarily the same as the original.  It is
1124            # merely an object supporting the iterator protocol, yielding
1125            # the same objects as the original one.
1126            # self.assertEqual(type(itorg), type(it))
1127            self.assertIsInstance(it, collections.abc.Iterator)
1128            self.assertEqual(dict(it), data)
1129
1130            it = pickle.loads(d)
1131            drop = next(it)
1132            d = pickle.dumps(it, proto)
1133            it = pickle.loads(d)
1134            del data[drop[0]]
1135            self.assertEqual(dict(it), data)
1136
1137    def test_valuesiterator_pickling(self):
1138        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
1139            data = {1:"a", 2:"b", 3:"c"}
1140            # data.values() isn't picklable, only its iterator
1141            it = iter(data.values())
1142            d = pickle.dumps(it, proto)
1143            it = pickle.loads(d)
1144            self.assertEqual(list(it), list(data.values()))
1145
1146            it = pickle.loads(d)
1147            drop = next(it)
1148            d = pickle.dumps(it, proto)
1149            it = pickle.loads(d)
1150            values = list(it) + [drop]
1151            self.assertEqual(sorted(values), sorted(list(data.values())))
1152
1153    def test_reverseiterator_pickling(self):
1154        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
1155            data = {1:"a", 2:"b", 3:"c"}
1156            it = reversed(data)
1157            d = pickle.dumps(it, proto)
1158            it = pickle.loads(d)
1159            self.assertEqual(list(it), list(reversed(data)))
1160
1161            it = pickle.loads(d)
1162            try:
1163                drop = next(it)
1164            except StopIteration:
1165                continue
1166            d = pickle.dumps(it, proto)
1167            it = pickle.loads(d)
1168            del data[drop]
1169            self.assertEqual(list(it), list(reversed(data)))
1170
1171    def test_reverseitemiterator_pickling(self):
1172        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
1173            data = {1:"a", 2:"b", 3:"c"}
1174            # dictviews aren't picklable, only their iterators
1175            itorg = reversed(data.items())
1176            d = pickle.dumps(itorg, proto)
1177            it = pickle.loads(d)
1178            # note that the type of the unpickled iterator
1179            # is not necessarily the same as the original.  It is
1180            # merely an object supporting the iterator protocol, yielding
1181            # the same objects as the original one.
1182            # self.assertEqual(type(itorg), type(it))
1183            self.assertIsInstance(it, collections.abc.Iterator)
1184            self.assertEqual(dict(it), data)
1185
1186            it = pickle.loads(d)
1187            drop = next(it)
1188            d = pickle.dumps(it, proto)
1189            it = pickle.loads(d)
1190            del data[drop[0]]
1191            self.assertEqual(dict(it), data)
1192
1193    def test_reversevaluesiterator_pickling(self):
1194        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
1195            data = {1:"a", 2:"b", 3:"c"}
1196            # data.values() isn't picklable, only its iterator
1197            it = reversed(data.values())
1198            d = pickle.dumps(it, proto)
1199            it = pickle.loads(d)
1200            self.assertEqual(list(it), list(reversed(data.values())))
1201
1202            it = pickle.loads(d)
1203            drop = next(it)
1204            d = pickle.dumps(it, proto)
1205            it = pickle.loads(d)
1206            values = list(it) + [drop]
1207            self.assertEqual(sorted(values), sorted(data.values()))
1208
1209    def test_instance_dict_getattr_str_subclass(self):
1210        class Foo:
1211            def __init__(self, msg):
1212                self.msg = msg
1213        f = Foo('123')
1214        class _str(str):
1215            pass
1216        self.assertEqual(f.msg, getattr(f, _str('msg')))
1217        self.assertEqual(f.msg, f.__dict__[_str('msg')])
1218
1219    def test_object_set_item_single_instance_non_str_key(self):
1220        class Foo: pass
1221        f = Foo()
1222        f.__dict__[1] = 1
1223        f.a = 'a'
1224        self.assertEqual(f.__dict__, {1:1, 'a':'a'})
1225
1226    def check_reentrant_insertion(self, mutate):
1227        # This object will trigger mutation of the dict when replaced
1228        # by another value.  Note this relies on refcounting: the test
1229        # won't achieve its purpose on fully-GCed Python implementations.
1230        class Mutating:
1231            def __del__(self):
1232                mutate(d)
1233
1234        d = {k: Mutating() for k in 'abcdefghijklmnopqr'}
1235        for k in list(d):
1236            d[k] = k
1237
1238    def test_reentrant_insertion(self):
1239        # Reentrant insertion shouldn't crash (see issue #22653)
1240        def mutate(d):
1241            d['b'] = 5
1242        self.check_reentrant_insertion(mutate)
1243
1244        def mutate(d):
1245            d.update(self.__dict__)
1246            d.clear()
1247        self.check_reentrant_insertion(mutate)
1248
1249        def mutate(d):
1250            while d:
1251                d.popitem()
1252        self.check_reentrant_insertion(mutate)
1253
1254    def test_merge_and_mutate(self):
1255        class X:
1256            def __hash__(self):
1257                return 0
1258
1259            def __eq__(self, o):
1260                other.clear()
1261                return False
1262
1263        l = [(i,0) for i in range(1, 1337)]
1264        other = dict(l)
1265        other[X()] = 0
1266        d = {X(): 0, 1: 1}
1267        self.assertRaises(RuntimeError, d.update, other)
1268
1269    def test_free_after_iterating(self):
1270        support.check_free_after_iterating(self, iter, dict)
1271        support.check_free_after_iterating(self, lambda d: iter(d.keys()), dict)
1272        support.check_free_after_iterating(self, lambda d: iter(d.values()), dict)
1273        support.check_free_after_iterating(self, lambda d: iter(d.items()), dict)
1274
1275    def test_equal_operator_modifying_operand(self):
1276        # test fix for seg fault reported in bpo-27945 part 3.
1277        class X():
1278            def __del__(self):
1279                dict_b.clear()
1280
1281            def __eq__(self, other):
1282                dict_a.clear()
1283                return True
1284
1285            def __hash__(self):
1286                return 13
1287
1288        dict_a = {X(): 0}
1289        dict_b = {X(): X()}
1290        self.assertTrue(dict_a == dict_b)
1291
1292        # test fix for seg fault reported in bpo-38588 part 1.
1293        class Y:
1294            def __eq__(self, other):
1295                dict_d.clear()
1296                return True
1297
1298        dict_c = {0: Y()}
1299        dict_d = {0: set()}
1300        self.assertTrue(dict_c == dict_d)
1301
1302    def test_fromkeys_operator_modifying_dict_operand(self):
1303        # test fix for seg fault reported in issue 27945 part 4a.
1304        class X(int):
1305            def __hash__(self):
1306                return 13
1307
1308            def __eq__(self, other):
1309                if len(d) > 1:
1310                    d.clear()
1311                return False
1312
1313        d = {}  # this is required to exist so that d can be constructed!
1314        d = {X(1): 1, X(2): 2}
1315        try:
1316            dict.fromkeys(d)  # shouldn't crash
1317        except RuntimeError:  # implementation defined
1318            pass
1319
1320    def test_fromkeys_operator_modifying_set_operand(self):
1321        # test fix for seg fault reported in issue 27945 part 4b.
1322        class X(int):
1323            def __hash__(self):
1324                return 13
1325
1326            def __eq__(self, other):
1327                if len(d) > 1:
1328                    d.clear()
1329                return False
1330
1331        d = {}  # this is required to exist so that d can be constructed!
1332        d = {X(1), X(2)}
1333        try:
1334            dict.fromkeys(d)  # shouldn't crash
1335        except RuntimeError:  # implementation defined
1336            pass
1337
1338    def test_dictitems_contains_use_after_free(self):
1339        class X:
1340            def __eq__(self, other):
1341                d.clear()
1342                return NotImplemented
1343
1344        d = {0: set()}
1345        (0, X()) in d.items()
1346
1347    def test_dict_contain_use_after_free(self):
1348        # bpo-40489
1349        class S(str):
1350            def __eq__(self, other):
1351                d.clear()
1352                return NotImplemented
1353
1354            def __hash__(self):
1355                return hash('test')
1356
1357        d = {S(): 'value'}
1358        self.assertFalse('test' in d)
1359
1360    def test_init_use_after_free(self):
1361        class X:
1362            def __hash__(self):
1363                pair[:] = []
1364                return 13
1365
1366        pair = [X(), 123]
1367        dict([pair])
1368
1369    def test_oob_indexing_dictiter_iternextitem(self):
1370        class X(int):
1371            def __del__(self):
1372                d.clear()
1373
1374        d = {i: X(i) for i in range(8)}
1375
1376        def iter_and_mutate():
1377            for result in d.items():
1378                if result[0] == 2:
1379                    d[2] = None # free d[2] --> X(2).__del__ was called
1380
1381        self.assertRaises(RuntimeError, iter_and_mutate)
1382
1383    def test_reversed(self):
1384        d = {"a": 1, "b": 2, "foo": 0, "c": 3, "d": 4}
1385        del d["foo"]
1386        r = reversed(d)
1387        self.assertEqual(list(r), list('dcba'))
1388        self.assertRaises(StopIteration, next, r)
1389
1390    def test_reverse_iterator_for_empty_dict(self):
1391        # bpo-38525: reversed iterator should work properly
1392
1393        # empty dict is directly used for reference count test
1394        self.assertEqual(list(reversed({})), [])
1395        self.assertEqual(list(reversed({}.items())), [])
1396        self.assertEqual(list(reversed({}.values())), [])
1397        self.assertEqual(list(reversed({}.keys())), [])
1398
1399        # dict() and {} don't trigger the same code path
1400        self.assertEqual(list(reversed(dict())), [])
1401        self.assertEqual(list(reversed(dict().items())), [])
1402        self.assertEqual(list(reversed(dict().values())), [])
1403        self.assertEqual(list(reversed(dict().keys())), [])
1404
1405    def test_reverse_iterator_for_shared_shared_dicts(self):
1406        class A:
1407            def __init__(self, x, y):
1408                if x: self.x = x
1409                if y: self.y = y
1410
1411        self.assertEqual(list(reversed(A(1, 2).__dict__)), ['y', 'x'])
1412        self.assertEqual(list(reversed(A(1, 0).__dict__)), ['x'])
1413        self.assertEqual(list(reversed(A(0, 1).__dict__)), ['y'])
1414
1415    def test_dict_copy_order(self):
1416        # bpo-34320
1417        od = collections.OrderedDict([('a', 1), ('b', 2)])
1418        od.move_to_end('a')
1419        expected = list(od.items())
1420
1421        copy = dict(od)
1422        self.assertEqual(list(copy.items()), expected)
1423
1424        # dict subclass doesn't override __iter__
1425        class CustomDict(dict):
1426            pass
1427
1428        pairs = [('a', 1), ('b', 2), ('c', 3)]
1429
1430        d = CustomDict(pairs)
1431        self.assertEqual(pairs, list(dict(d).items()))
1432
1433        class CustomReversedDict(dict):
1434            def keys(self):
1435                return reversed(list(dict.keys(self)))
1436
1437            __iter__ = keys
1438
1439            def items(self):
1440                return reversed(dict.items(self))
1441
1442        d = CustomReversedDict(pairs)
1443        self.assertEqual(pairs[::-1], list(dict(d).items()))
1444
1445    @support.cpython_only
1446    def test_dict_items_result_gc(self):
1447        # bpo-42536: dict.items's tuple-reuse speed trick breaks the GC's
1448        # assumptions about what can be untracked. Make sure we re-track result
1449        # tuples whenever we reuse them.
1450        it = iter({None: []}.items())
1451        gc.collect()
1452        # That GC collection probably untracked the recycled internal result
1453        # tuple, which is initialized to (None, None). Make sure it's re-tracked
1454        # when it's mutated and returned from __next__:
1455        self.assertTrue(gc.is_tracked(next(it)))
1456
1457    @support.cpython_only
1458    def test_dict_items_result_gc_reversed(self):
1459        # Same as test_dict_items_result_gc above, but reversed.
1460        it = reversed({None: []}.items())
1461        gc.collect()
1462        self.assertTrue(gc.is_tracked(next(it)))
1463
1464    def test_str_nonstr(self):
1465        # cpython uses a different lookup function if the dict only contains
1466        # `str` keys. Make sure the unoptimized path is used when a non-`str`
1467        # key appears.
1468
1469        class StrSub(str):
1470            pass
1471
1472        eq_count = 0
1473        # This class compares equal to the string 'key3'
1474        class Key3:
1475            def __hash__(self):
1476                return hash('key3')
1477
1478            def __eq__(self, other):
1479                nonlocal eq_count
1480                if isinstance(other, Key3) or isinstance(other, str) and other == 'key3':
1481                    eq_count += 1
1482                    return True
1483                return False
1484
1485        key3_1 = StrSub('key3')
1486        key3_2 = Key3()
1487        key3_3 = Key3()
1488
1489        dicts = []
1490
1491        # Create dicts of the form `{'key1': 42, 'key2': 43, key3: 44}` in a
1492        # bunch of different ways. In all cases, `key3` is not of type `str`.
1493        # `key3_1` is a `str` subclass and `key3_2` is a completely unrelated
1494        # type.
1495        for key3 in (key3_1, key3_2):
1496            # A literal
1497            dicts.append({'key1': 42, 'key2': 43, key3: 44})
1498
1499            # key3 inserted via `dict.__setitem__`
1500            d = {'key1': 42, 'key2': 43}
1501            d[key3] = 44
1502            dicts.append(d)
1503
1504            # key3 inserted via `dict.setdefault`
1505            d = {'key1': 42, 'key2': 43}
1506            self.assertEqual(d.setdefault(key3, 44), 44)
1507            dicts.append(d)
1508
1509            # key3 inserted via `dict.update`
1510            d = {'key1': 42, 'key2': 43}
1511            d.update({key3: 44})
1512            dicts.append(d)
1513
1514            # key3 inserted via `dict.__ior__`
1515            d = {'key1': 42, 'key2': 43}
1516            d |= {key3: 44}
1517            dicts.append(d)
1518
1519            # `dict(iterable)`
1520            def make_pairs():
1521                yield ('key1', 42)
1522                yield ('key2', 43)
1523                yield (key3, 44)
1524            d = dict(make_pairs())
1525            dicts.append(d)
1526
1527            # `dict.copy`
1528            d = d.copy()
1529            dicts.append(d)
1530
1531            # dict comprehension
1532            d = {key: 42 + i for i,key in enumerate(['key1', 'key2', key3])}
1533            dicts.append(d)
1534
1535        for d in dicts:
1536            with self.subTest(d=d):
1537                self.assertEqual(d.get('key1'), 42)
1538
1539                # Try to make an object that is of type `str` and is equal to
1540                # `'key1'`, but (at least on cpython) is a different object.
1541                noninterned_key1 = 'ke'
1542                noninterned_key1 += 'y1'
1543                if support.check_impl_detail(cpython=True):
1544                    # suppress a SyntaxWarning
1545                    interned_key1 = 'key1'
1546                    self.assertFalse(noninterned_key1 is interned_key1)
1547                self.assertEqual(d.get(noninterned_key1), 42)
1548
1549                self.assertEqual(d.get('key3'), 44)
1550                self.assertEqual(d.get(key3_1), 44)
1551                self.assertEqual(d.get(key3_2), 44)
1552
1553                # `key3_3` itself is definitely not a dict key, so make sure
1554                # that `__eq__` gets called.
1555                #
1556                # Note that this might not hold for `key3_1` and `key3_2`
1557                # because they might be the same object as one of the dict keys,
1558                # in which case implementations are allowed to skip the call to
1559                # `__eq__`.
1560                eq_count = 0
1561                self.assertEqual(d.get(key3_3), 44)
1562                self.assertGreaterEqual(eq_count, 1)
1563
1564
1565class CAPITest(unittest.TestCase):
1566
1567    # Test _PyDict_GetItem_KnownHash()
1568    @support.cpython_only
1569    def test_getitem_knownhash(self):
1570        _testcapi = import_helper.import_module('_testcapi')
1571        dict_getitem_knownhash = _testcapi.dict_getitem_knownhash
1572
1573        d = {'x': 1, 'y': 2, 'z': 3}
1574        self.assertEqual(dict_getitem_knownhash(d, 'x', hash('x')), 1)
1575        self.assertEqual(dict_getitem_knownhash(d, 'y', hash('y')), 2)
1576        self.assertEqual(dict_getitem_knownhash(d, 'z', hash('z')), 3)
1577
1578        # not a dict
1579        self.assertRaises(SystemError, dict_getitem_knownhash, [], 1, hash(1))
1580        # key does not exist
1581        self.assertRaises(KeyError, dict_getitem_knownhash, {}, 1, hash(1))
1582
1583        class Exc(Exception): pass
1584        class BadEq:
1585            def __eq__(self, other):
1586                raise Exc
1587            def __hash__(self):
1588                return 7
1589
1590        k1, k2 = BadEq(), BadEq()
1591        d = {k1: 1}
1592        self.assertEqual(dict_getitem_knownhash(d, k1, hash(k1)), 1)
1593        self.assertRaises(Exc, dict_getitem_knownhash, d, k2, hash(k2))
1594
1595
1596from test import mapping_tests
1597
1598class GeneralMappingTests(mapping_tests.BasicTestMappingProtocol):
1599    type2test = dict
1600
1601class Dict(dict):
1602    pass
1603
1604class SubclassMappingTests(mapping_tests.BasicTestMappingProtocol):
1605    type2test = Dict
1606
1607
1608if __name__ == "__main__":
1609    unittest.main()
1610