Python code coverage for Lib/test/test_unpack_ex.py

#	count	content
1	n/a	# Tests for extended unpacking, starred expressions.
2	n/a
3	n/a	doctests = """
4	n/a
5	n/a	Unpack tuple
6	n/a
7	n/a	>>> t = (1, 2, 3)
8	n/a	>>> a, *b, c = t
9	n/a	>>> a == 1 and b == [2] and c == 3
10	n/a	True
11	n/a
12	n/a	Unpack list
13	n/a
14	n/a	>>> l = [4, 5, 6]
15	n/a	>>> a, *b = l
16	n/a	>>> a == 4 and b == [5, 6]
17	n/a	True
18	n/a
19	n/a	Unpack implied tuple
20	n/a
21	n/a	>>> *a, = 7, 8, 9
22	n/a	>>> a == [7, 8, 9]
23	n/a	True
24	n/a
25	n/a	Unpack string... fun!
26	n/a
27	n/a	>>> a, *b = 'one'
28	n/a	>>> a == 'o' and b == ['n', 'e']
29	n/a	True
30	n/a
31	n/a	Unpack long sequence
32	n/a
33	n/a	>>> a, b, c, *d, e, f, g = range(10)
34	n/a	>>> (a, b, c, d, e, f, g) == (0, 1, 2, [3, 4, 5, 6], 7, 8, 9)
35	n/a	True
36	n/a
37	n/a	Unpack short sequence
38	n/a
39	n/a	>>> a, *b, c = (1, 2)
40	n/a	>>> a == 1 and c == 2 and b == []
41	n/a	True
42	n/a
43	n/a	Unpack generic sequence
44	n/a
45	n/a	>>> class Seq:
46	n/a	... def __getitem__(self, i):
47	n/a	... if i >= 0 and i < 3: return i
48	n/a	... raise IndexError
49	n/a	...
50	n/a	>>> a, *b = Seq()
51	n/a	>>> a == 0 and b == [1, 2]
52	n/a	True
53	n/a
54	n/a	Unpack in for statement
55	n/a
56	n/a	>>> for a, *b, c in [(1,2,3), (4,5,6,7)]:
57	n/a	... print(a, b, c)
58	n/a	...
59	n/a	1 [2] 3
60	n/a	4 [5, 6] 7
61	n/a
62	n/a	Unpack in list
63	n/a
64	n/a	>>> [a, *b, c] = range(5)
65	n/a	>>> a == 0 and b == [1, 2, 3] and c == 4
66	n/a	True
67	n/a
68	n/a	Multiple targets
69	n/a
70	n/a	>>> a, b, c = d, e = range(5)
71	n/a	>>> a == 0 and b == [1, 2, 3] and c == 4 and d == [0, 1, 2, 3] and e == 4
72	n/a	True
73	n/a
74	n/a	Assignment unpacking
75	n/a
76	n/a	>>> a, b, *c = range(5)
77	n/a	>>> a, b, c
78	n/a	(0, 1, [2, 3, 4])
79	n/a	>>> a, b, c = a, b, c
80	n/a	>>> a, b, c
81	n/a	([0, 1, 2], 3, 4)
82	n/a
83	n/a	Set display element unpacking
84	n/a
85	n/a	>>> a = [1, 2, 3]
86	n/a	>>> sorted({1, *a, 0, 4})
87	n/a	[0, 1, 2, 3, 4]
88	n/a
89	n/a	>>> {1, *1, 0, 4}
90	n/a	Traceback (most recent call last):
91	n/a	...
92	n/a	TypeError: 'int' object is not iterable
93	n/a
94	n/a	Dict display element unpacking
95	n/a
96	n/a	>>> kwds = {'z': 0, 'w': 12}
97	n/a	>>> sorted({'x': 1, 'y': 2, **kwds}.items())
98	n/a	[('w', 12), ('x', 1), ('y', 2), ('z', 0)]
99	n/a
100	n/a	>>> sorted({{'x': 1}, 'y': 2, {'z': 3}}.items())
101	n/a	[('x', 1), ('y', 2), ('z', 3)]
102	n/a
103	n/a	>>> sorted({{'x': 1}, 'y': 2, {'x': 3}}.items())
104	n/a	[('x', 3), ('y', 2)]
105	n/a
106	n/a	>>> sorted({{'x': 1}, {'x': 3}, 'x': 4}.items())
107	n/a	[('x', 4)]
108	n/a
109	n/a	>>> {**{}}
110	n/a	{}
111	n/a
112	n/a	>>> a = {}
113	n/a	>>> {**a}[0] = 1
114	n/a	>>> a
115	n/a	{}
116	n/a
117	n/a	>>> {**1}
118	n/a	Traceback (most recent call last):
119	n/a	...
120	n/a	TypeError: 'int' object is not a mapping
121	n/a
122	n/a	>>> {**[]}
123	n/a	Traceback (most recent call last):
124	n/a	...
125	n/a	TypeError: 'list' object is not a mapping
126	n/a
127	n/a	>>> len(eval("{" + ", ".join("**{{{}: {}}}".format(i, i)
128	n/a	... for i in range(1000)) + "}"))
129	n/a	1000
130	n/a
131	n/a	>>> {0:1, **{0:2}, 0:3, 0:4}
132	n/a	{0: 4}
133	n/a
134	n/a	List comprehension element unpacking
135	n/a
136	n/a	>>> a, b, c = [0, 1, 2], 3, 4
137	n/a	>>> [*a, b, c]
138	n/a	[0, 1, 2, 3, 4]
139	n/a
140	n/a	>>> l = [a, (3, 4), {5}, {6: None}, (i for i in range(7, 10))]
141	n/a	>>> [*item for item in l]
142	n/a	Traceback (most recent call last):
143	n/a	...
144	n/a	SyntaxError: iterable unpacking cannot be used in comprehension
145	n/a
146	n/a	>>> [*[0, 1] for i in range(10)]
147	n/a	Traceback (most recent call last):
148	n/a	...
149	n/a	SyntaxError: iterable unpacking cannot be used in comprehension
150	n/a
151	n/a	>>> [*'a' for i in range(10)]
152	n/a	Traceback (most recent call last):
153	n/a	...
154	n/a	SyntaxError: iterable unpacking cannot be used in comprehension
155	n/a
156	n/a	>>> [*[] for i in range(10)]
157	n/a	Traceback (most recent call last):
158	n/a	...
159	n/a	SyntaxError: iterable unpacking cannot be used in comprehension
160	n/a
161	n/a	Generator expression in function arguments
162	n/a
163	n/a	>>> list(*x for x in (range(5) for i in range(3)))
164	n/a	Traceback (most recent call last):
165	n/a	...
166	n/a	list(*x for x in (range(5) for i in range(3)))
167	n/a	^
168	n/a	SyntaxError: invalid syntax
169	n/a
170	n/a	>>> dict(**x for x in [{1:2}])
171	n/a	Traceback (most recent call last):
172	n/a	...
173	n/a	dict(**x for x in [{1:2}])
174	n/a	^
175	n/a	SyntaxError: invalid syntax
176	n/a
177	n/a	Iterable argument unpacking
178	n/a
179	n/a	>>> print([1], [2], 3)
180	n/a	1 2 3
181	n/a
182	n/a	Make sure that they don't corrupt the passed-in dicts.
183	n/a
184	n/a	>>> def f(x, y):
185	n/a	... print(x, y)
186	n/a	...
187	n/a	>>> original_dict = {'x': 1}
188	n/a	>>> f(**original_dict, y=2)
189	n/a	1 2
190	n/a	>>> original_dict
191	n/a	{'x': 1}
192	n/a
193	n/a	Now for some failures
194	n/a
195	n/a	Make sure the raised errors are right for keyword argument unpackings
196	n/a
197	n/a	>>> from collections.abc import MutableMapping
198	n/a	>>> class CrazyDict(MutableMapping):
199	n/a	... def __init__(self):
200	n/a	... self.d = {}
201	n/a	...
202	n/a	... def __iter__(self):
203	n/a	... for x in self.d.__iter__():
204	n/a	... if x == 'c':
205	n/a	... self.d['z'] = 10
206	n/a	... yield x
207	n/a	...
208	n/a	... def __getitem__(self, k):
209	n/a	... return self.d[k]
210	n/a	...
211	n/a	... def __len__(self):
212	n/a	... return len(self.d)
213	n/a	...
214	n/a	... def __setitem__(self, k, v):
215	n/a	... self.d[k] = v
216	n/a	...
217	n/a	... def __delitem__(self, k):
218	n/a	... del self.d[k]
219	n/a	...
220	n/a	>>> d = CrazyDict()
221	n/a	>>> d.d = {chr(ord('a') + x): x for x in range(5)}
222	n/a	>>> e = {**d}
223	n/a	Traceback (most recent call last):
224	n/a	...
225	n/a	RuntimeError: dictionary changed size during iteration
226	n/a
227	n/a	>>> d.d = {chr(ord('a') + x): x for x in range(5)}
228	n/a	>>> def f(**kwargs): print(kwargs)
229	n/a	>>> f(**d)
230	n/a	Traceback (most recent call last):
231	n/a	...
232	n/a	RuntimeError: dictionary changed size during iteration
233	n/a
234	n/a	Overridden parameters
235	n/a
236	n/a	>>> f(x=5, **{'x': 3}, y=2)
237	n/a	Traceback (most recent call last):
238	n/a	...
239	n/a	TypeError: f() got multiple values for keyword argument 'x'
240	n/a
241	n/a	>>> f(**{'x': 3}, x=5, y=2)
242	n/a	Traceback (most recent call last):
243	n/a	...
244	n/a	TypeError: f() got multiple values for keyword argument 'x'
245	n/a
246	n/a	>>> f({'x': 3}, {'x': 5}, y=2)
247	n/a	Traceback (most recent call last):
248	n/a	...
249	n/a	TypeError: f() got multiple values for keyword argument 'x'
250	n/a
251	n/a	>>> f(x=5, {'x': 3}, {'x': 2})
252	n/a	Traceback (most recent call last):
253	n/a	...
254	n/a	TypeError: f() got multiple values for keyword argument 'x'
255	n/a
256	n/a	>>> f({1: 3}, {1: 5})
257	n/a	Traceback (most recent call last):
258	n/a	...
259	n/a	TypeError: f() keywords must be strings
260	n/a
261	n/a	Unpacking non-sequence
262	n/a
263	n/a	>>> a, *b = 7
264	n/a	Traceback (most recent call last):
265	n/a	...
266	n/a	TypeError: 'int' object is not iterable
267	n/a
268	n/a	Unpacking sequence too short
269	n/a
270	n/a	>>> a, *b, c, d, e = Seq()
271	n/a	Traceback (most recent call last):
272	n/a	...
273	n/a	ValueError: not enough values to unpack (expected at least 4, got 3)
274	n/a
275	n/a	Unpacking sequence too short and target appears last
276	n/a
277	n/a	>>> a, b, c, d, *e = Seq()
278	n/a	Traceback (most recent call last):
279	n/a	...
280	n/a	ValueError: not enough values to unpack (expected at least 4, got 3)
281	n/a
282	n/a	Unpacking a sequence where the test for too long raises a different kind of
283	n/a	error
284	n/a
285	n/a	>>> class BozoError(Exception):
286	n/a	... pass
287	n/a	...
288	n/a	>>> class BadSeq:
289	n/a	... def __getitem__(self, i):
290	n/a	... if i >= 0 and i < 3:
291	n/a	... return i
292	n/a	... elif i == 3:
293	n/a	... raise BozoError
294	n/a	... else:
295	n/a	... raise IndexError
296	n/a	...
297	n/a
298	n/a	Trigger code while not expecting an IndexError (unpack sequence too long, wrong
299	n/a	error)
300	n/a
301	n/a	>>> a, *b, c, d, e = BadSeq()
302	n/a	Traceback (most recent call last):
303	n/a	...
304	n/a	test.test_unpack_ex.BozoError
305	n/a
306	n/a	Now some general starred expressions (all fail).
307	n/a
308	n/a	>>> a, b, c, d, e = range(10) # doctest:+ELLIPSIS
309	n/a	Traceback (most recent call last):
310	n/a	...
311	n/a	SyntaxError: two starred expressions in assignment
312	n/a
313	n/a	>>> [b, c] = range(10) # doctest:+ELLIPSIS
314	n/a	Traceback (most recent call last):
315	n/a	...
316	n/a	SyntaxError: two starred expressions in assignment
317	n/a
318	n/a	>>> *a = range(10) # doctest:+ELLIPSIS
319	n/a	Traceback (most recent call last):
320	n/a	...
321	n/a	SyntaxError: starred assignment target must be in a list or tuple
322	n/a
323	n/a	>>> *a # doctest:+ELLIPSIS
324	n/a	Traceback (most recent call last):
325	n/a	...
326	n/a	SyntaxError: can't use starred expression here
327	n/a
328	n/a	>>> *1 # doctest:+ELLIPSIS
329	n/a	Traceback (most recent call last):
330	n/a	...
331	n/a	SyntaxError: can't use starred expression here
332	n/a
333	n/a	>>> x = *a # doctest:+ELLIPSIS
334	n/a	Traceback (most recent call last):
335	n/a	...
336	n/a	SyntaxError: can't use starred expression here
337	n/a
338	n/a	Some size constraints (all fail.)
339	n/a
340	n/a	>>> s = ", ".join("a%d" % i for i in range(1<<8)) + ", *rest = range(1<<8 + 1)"
341	n/a	>>> compile(s, 'test', 'exec') # doctest:+ELLIPSIS
342	n/a	Traceback (most recent call last):
343	n/a	...
344	n/a	SyntaxError: too many expressions in star-unpacking assignment
345	n/a
346	n/a	>>> s = ", ".join("a%d" % i for i in range(1<<8 + 1)) + ", *rest = range(1<<8 + 2)"
347	n/a	>>> compile(s, 'test', 'exec') # doctest:+ELLIPSIS
348	n/a	Traceback (most recent call last):
349	n/a	...
350	n/a	SyntaxError: too many expressions in star-unpacking assignment
351	n/a
352	n/a	(there is an additional limit, on the number of expressions after the
353	n/a	'*rest', but it's 1<<24 and testing it takes too much memory.)
354	n/a
355	n/a	"""
356	n/a
357	n/a	__test__ = {'doctests' : doctests}
358	n/a
359	n/a	def test_main(verbose=False):
360	n/a	from test import support
361	n/a	from test import test_unpack_ex
362	n/a	support.run_doctest(test_unpack_ex, verbose)
363	n/a
364	n/a	if __name__ == "__main__":
365	n/a	test_main(verbose=True)