Python code coverage for Lib/test/test_super.py

#	count	content
1	n/a	"""Unit tests for zero-argument super() & related machinery."""
2	n/a
3	n/a	import unittest
4	n/a	import warnings
5	n/a	from test.support import check_warnings
6	n/a
7	n/a
8	n/a	class A:
9	n/a	def f(self):
10	n/a	return 'A'
11	n/a	@classmethod
12	n/a	def cm(cls):
13	n/a	return (cls, 'A')
14	n/a
15	n/a	class B(A):
16	n/a	def f(self):
17	n/a	return super().f() + 'B'
18	n/a	@classmethod
19	n/a	def cm(cls):
20	n/a	return (cls, super().cm(), 'B')
21	n/a
22	n/a	class C(A):
23	n/a	def f(self):
24	n/a	return super().f() + 'C'
25	n/a	@classmethod
26	n/a	def cm(cls):
27	n/a	return (cls, super().cm(), 'C')
28	n/a
29	n/a	class D(C, B):
30	n/a	def f(self):
31	n/a	return super().f() + 'D'
32	n/a	def cm(cls):
33	n/a	return (cls, super().cm(), 'D')
34	n/a
35	n/a	class E(D):
36	n/a	pass
37	n/a
38	n/a	class F(E):
39	n/a	f = E.f
40	n/a
41	n/a	class G(A):
42	n/a	pass
43	n/a
44	n/a
45	n/a	class TestSuper(unittest.TestCase):
46	n/a
47	n/a	def tearDown(self):
48	n/a	# This fixes the damage that test_various___class___pathologies does.
49	n/a	nonlocal __class__
50	n/a	__class__ = TestSuper
51	n/a
52	n/a	def test_basics_working(self):
53	n/a	self.assertEqual(D().f(), 'ABCD')
54	n/a
55	n/a	def test_class_getattr_working(self):
56	n/a	self.assertEqual(D.f(D()), 'ABCD')
57	n/a
58	n/a	def test_subclass_no_override_working(self):
59	n/a	self.assertEqual(E().f(), 'ABCD')
60	n/a	self.assertEqual(E.f(E()), 'ABCD')
61	n/a
62	n/a	def test_unbound_method_transfer_working(self):
63	n/a	self.assertEqual(F().f(), 'ABCD')
64	n/a	self.assertEqual(F.f(F()), 'ABCD')
65	n/a
66	n/a	def test_class_methods_still_working(self):
67	n/a	self.assertEqual(A.cm(), (A, 'A'))
68	n/a	self.assertEqual(A().cm(), (A, 'A'))
69	n/a	self.assertEqual(G.cm(), (G, 'A'))
70	n/a	self.assertEqual(G().cm(), (G, 'A'))
71	n/a
72	n/a	def test_super_in_class_methods_working(self):
73	n/a	d = D()
74	n/a	self.assertEqual(d.cm(), (d, (D, (D, (D, 'A'), 'B'), 'C'), 'D'))
75	n/a	e = E()
76	n/a	self.assertEqual(e.cm(), (e, (E, (E, (E, 'A'), 'B'), 'C'), 'D'))
77	n/a
78	n/a	def test_super_with_closure(self):
79	n/a	# Issue4360: super() did not work in a function that
80	n/a	# contains a closure
81	n/a	class E(A):
82	n/a	def f(self):
83	n/a	def nested():
84	n/a	self
85	n/a	return super().f() + 'E'
86	n/a
87	n/a	self.assertEqual(E().f(), 'AE')
88	n/a
89	n/a	def test_various___class___pathologies(self):
90	n/a	# See issue #12370
91	n/a	class X(A):
92	n/a	def f(self):
93	n/a	return super().f()
94	n/a	__class__ = 413
95	n/a	x = X()
96	n/a	self.assertEqual(x.f(), 'A')
97	n/a	self.assertEqual(x.__class__, 413)
98	n/a	class X:
99	n/a	x = __class__
100	n/a	def f():
101	n/a	__class__
102	n/a	self.assertIs(X.x, type(self))
103	n/a	with self.assertRaises(NameError) as e:
104	n/a	exec("""class X:
105	n/a	__class__
106	n/a	def f():
107	n/a	__class__""", globals(), {})
108	n/a	self.assertIs(type(e.exception), NameError) # Not UnboundLocalError
109	n/a	class X:
110	n/a	global __class__
111	n/a	__class__ = 42
112	n/a	def f():
113	n/a	__class__
114	n/a	self.assertEqual(globals()["__class__"], 42)
115	n/a	del globals()["__class__"]
116	n/a	self.assertNotIn("__class__", X.__dict__)
117	n/a	class X:
118	n/a	nonlocal __class__
119	n/a	__class__ = 42
120	n/a	def f():
121	n/a	__class__
122	n/a	self.assertEqual(__class__, 42)
123	n/a
124	n/a	def test___class___instancemethod(self):
125	n/a	# See issue #14857
126	n/a	class X:
127	n/a	def f(self):
128	n/a	return __class__
129	n/a	self.assertIs(X().f(), X)
130	n/a
131	n/a	def test___class___classmethod(self):
132	n/a	# See issue #14857
133	n/a	class X:
134	n/a	@classmethod
135	n/a	def f(cls):
136	n/a	return __class__
137	n/a	self.assertIs(X.f(), X)
138	n/a
139	n/a	def test___class___staticmethod(self):
140	n/a	# See issue #14857
141	n/a	class X:
142	n/a	@staticmethod
143	n/a	def f():
144	n/a	return __class__
145	n/a	self.assertIs(X.f(), X)
146	n/a
147	n/a	def test___class___new(self):
148	n/a	# See issue #23722
149	n/a	# Ensure zero-arg super() works as soon as type.__new__() is completed
150	n/a	test_class = None
151	n/a
152	n/a	class Meta(type):
153	n/a	def __new__(cls, name, bases, namespace):
154	n/a	nonlocal test_class
155	n/a	self = super().__new__(cls, name, bases, namespace)
156	n/a	test_class = self.f()
157	n/a	return self
158	n/a
159	n/a	class A(metaclass=Meta):
160	n/a	@staticmethod
161	n/a	def f():
162	n/a	return __class__
163	n/a
164	n/a	self.assertIs(test_class, A)
165	n/a
166	n/a	def test___class___delayed(self):
167	n/a	# See issue #23722
168	n/a	test_namespace = None
169	n/a
170	n/a	class Meta(type):
171	n/a	def __new__(cls, name, bases, namespace):
172	n/a	nonlocal test_namespace
173	n/a	test_namespace = namespace
174	n/a	return None
175	n/a
176	n/a	# This case shouldn't trigger the __classcell__ deprecation warning
177	n/a	with check_warnings() as w:
178	n/a	warnings.simplefilter("always", DeprecationWarning)
179	n/a	class A(metaclass=Meta):
180	n/a	@staticmethod
181	n/a	def f():
182	n/a	return __class__
183	n/a	self.assertEqual(w.warnings, [])
184	n/a
185	n/a	self.assertIs(A, None)
186	n/a
187	n/a	B = type("B", (), test_namespace)
188	n/a	self.assertIs(B.f(), B)
189	n/a
190	n/a	def test___class___mro(self):
191	n/a	# See issue #23722
192	n/a	test_class = None
193	n/a
194	n/a	class Meta(type):
195	n/a	def mro(self):
196	n/a	# self.f() doesn't work yet...
197	n/a	self.__dict__["f"]()
198	n/a	return super().mro()
199	n/a
200	n/a	class A(metaclass=Meta):
201	n/a	def f():
202	n/a	nonlocal test_class
203	n/a	test_class = __class__
204	n/a
205	n/a	self.assertIs(test_class, A)
206	n/a
207	n/a	def test___classcell___expected_behaviour(self):
208	n/a	# See issue #23722
209	n/a	class Meta(type):
210	n/a	def __new__(cls, name, bases, namespace):
211	n/a	nonlocal namespace_snapshot
212	n/a	namespace_snapshot = namespace.copy()
213	n/a	return super().__new__(cls, name, bases, namespace)
214	n/a
215	n/a	# __classcell__ is injected into the class namespace by the compiler
216	n/a	# when at least one method needs it, and should be omitted otherwise
217	n/a	namespace_snapshot = None
218	n/a	class WithoutClassRef(metaclass=Meta):
219	n/a	pass
220	n/a	self.assertNotIn("__classcell__", namespace_snapshot)
221	n/a
222	n/a	# With zero-arg super() or an explicit __class__ reference,
223	n/a	# __classcell__ is the exact cell reference to be populated by
224	n/a	# type.__new__
225	n/a	namespace_snapshot = None
226	n/a	class WithClassRef(metaclass=Meta):
227	n/a	def f(self):
228	n/a	return __class__
229	n/a
230	n/a	class_cell = namespace_snapshot["__classcell__"]
231	n/a	method_closure = WithClassRef.f.__closure__
232	n/a	self.assertEqual(len(method_closure), 1)
233	n/a	self.assertIs(class_cell, method_closure[0])
234	n/a	# Ensure the cell reference doesn't get turned into an attribute
235	n/a	with self.assertRaises(AttributeError):
236	n/a	WithClassRef.__classcell__
237	n/a
238	n/a	def test___classcell___missing(self):
239	n/a	# See issue #23722
240	n/a	# Some metaclasses may not pass the original namespace to type.__new__
241	n/a	# We test that case here by forcibly deleting __classcell__
242	n/a	class Meta(type):
243	n/a	def __new__(cls, name, bases, namespace):
244	n/a	namespace.pop('__classcell__', None)
245	n/a	return super().__new__(cls, name, bases, namespace)
246	n/a
247	n/a	# The default case should continue to work without any warnings
248	n/a	with check_warnings() as w:
249	n/a	warnings.simplefilter("always", DeprecationWarning)
250	n/a	class WithoutClassRef(metaclass=Meta):
251	n/a	pass
252	n/a	self.assertEqual(w.warnings, [])
253	n/a
254	n/a	# With zero-arg super() or an explicit __class__ reference, we expect
255	n/a	# __build_class__ to emit a DeprecationWarning complaining that
256	n/a	# __class__ was not set, and asking if __classcell__ was propagated
257	n/a	# to type.__new__.
258	n/a	# In Python 3.7, that warning will become a RuntimeError.
259	n/a	expected_warning = (
260	n/a	'__class__ not set.*__classcell__ propagated',
261	n/a	DeprecationWarning
262	n/a	)
263	n/a	with check_warnings(expected_warning):
264	n/a	warnings.simplefilter("always", DeprecationWarning)
265	n/a	class WithClassRef(metaclass=Meta):
266	n/a	def f(self):
267	n/a	return __class__
268	n/a	# Check __class__ still gets set despite the warning
269	n/a	self.assertIs(WithClassRef().f(), WithClassRef)
270	n/a
271	n/a	# Check the warning is turned into an error as expected
272	n/a	with warnings.catch_warnings():
273	n/a	warnings.simplefilter("error", DeprecationWarning)
274	n/a	with self.assertRaises(DeprecationWarning):
275	n/a	class WithClassRef(metaclass=Meta):
276	n/a	def f(self):
277	n/a	return __class__
278	n/a
279	n/a	def test___classcell___overwrite(self):
280	n/a	# See issue #23722
281	n/a	# Overwriting __classcell__ with nonsense is explicitly prohibited
282	n/a	class Meta(type):
283	n/a	def __new__(cls, name, bases, namespace, cell):
284	n/a	namespace['__classcell__'] = cell
285	n/a	return super().__new__(cls, name, bases, namespace)
286	n/a
287	n/a	for bad_cell in (None, 0, "", object()):
288	n/a	with self.subTest(bad_cell=bad_cell):
289	n/a	with self.assertRaises(TypeError):
290	n/a	class A(metaclass=Meta, cell=bad_cell):
291	n/a	pass
292	n/a
293	n/a	def test___classcell___wrong_cell(self):
294	n/a	# See issue #23722
295	n/a	# Pointing the cell reference at the wrong class is also prohibited
296	n/a	class Meta(type):
297	n/a	def __new__(cls, name, bases, namespace):
298	n/a	cls = super().__new__(cls, name, bases, namespace)
299	n/a	B = type("B", (), namespace)
300	n/a	return cls
301	n/a
302	n/a	with self.assertRaises(TypeError):
303	n/a	class A(metaclass=Meta):
304	n/a	def f(self):
305	n/a	return __class__
306	n/a
307	n/a	def test_obscure_super_errors(self):
308	n/a	def f():
309	n/a	super()
310	n/a	self.assertRaises(RuntimeError, f)
311	n/a	def f(x):
312	n/a	del x
313	n/a	super()
314	n/a	self.assertRaises(RuntimeError, f, None)
315	n/a	class X:
316	n/a	def f(x):
317	n/a	nonlocal __class__
318	n/a	del __class__
319	n/a	super()
320	n/a	self.assertRaises(RuntimeError, X().f)
321	n/a
322	n/a	def test_cell_as_self(self):
323	n/a	class X:
324	n/a	def meth(self):
325	n/a	super()
326	n/a
327	n/a	def f():
328	n/a	k = X()
329	n/a	def g():
330	n/a	return k
331	n/a	return g
332	n/a	c = f().__closure__[0]
333	n/a	self.assertRaises(TypeError, X.meth, c)
334	n/a
335	n/a	def test_super_init_leaks(self):
336	n/a	# Issue #26718: super.__init__ leaked memory if called multiple times.
337	n/a	# This will be caught by regrtest.py -R if this leak.
338	n/a	# NOTE: Despite the use in the test a direct call of super.__init__
339	n/a	# is not endorsed.
340	n/a	sp = super(float, 1.0)
341	n/a	for i in range(1000):
342	n/a	super.__init__(sp, int, i)
343	n/a
344	n/a
345	n/a	if __name__ == "__main__":
346	n/a	unittest.main()