python (3.11.7)
1 import doctest
2 import unittest
3
4
5 doctests = """
6
7 Unpack tuple
8
9 >>> t = (1, 2, 3)
10 >>> a, b, c = t
11 >>> a == 1 and b == 2 and c == 3
12 True
13
14 Unpack list
15
16 >>> l = [4, 5, 6]
17 >>> a, b, c = l
18 >>> a == 4 and b == 5 and c == 6
19 True
20
21 Unpack implied tuple
22
23 >>> a, b, c = 7, 8, 9
24 >>> a == 7 and b == 8 and c == 9
25 True
26
27 Unpack string... fun!
28
29 >>> a, b, c = 'one'
30 >>> a == 'o' and b == 'n' and c == 'e'
31 True
32
33 Unpack generic sequence
34
35 >>> class Seq:
36 ... def __getitem__(self, i):
37 ... if i >= 0 and i < 3: return i
38 ... raise IndexError
39 ...
40 >>> a, b, c = Seq()
41 >>> a == 0 and b == 1 and c == 2
42 True
43
44 Single element unpacking, with extra syntax
45
46 >>> st = (99,)
47 >>> sl = [100]
48 >>> a, = st
49 >>> a
50 99
51 >>> b, = sl
52 >>> b
53 100
54
55 Now for some failures
56
57 Unpacking non-sequence
58
59 >>> a, b, c = 7
60 Traceback (most recent call last):
61 ...
62 TypeError: cannot unpack non-iterable int object
63
64 Unpacking tuple of wrong size
65
66 >>> a, b = t
67 Traceback (most recent call last):
68 ...
69 ValueError: too many values to unpack (expected 2)
70
71 Unpacking tuple of wrong size
72
73 >>> a, b = l
74 Traceback (most recent call last):
75 ...
76 ValueError: too many values to unpack (expected 2)
77
78 Unpacking sequence too short
79
80 >>> a, b, c, d = Seq()
81 Traceback (most recent call last):
82 ...
83 ValueError: not enough values to unpack (expected 4, got 3)
84
85 Unpacking sequence too long
86
87 >>> a, b = Seq()
88 Traceback (most recent call last):
89 ...
90 ValueError: too many values to unpack (expected 2)
91
92 Unpacking a sequence where the test for too long raises a different kind of
93 error
94
95 >>> class BozoError(Exception):
96 ... pass
97 ...
98 >>> class BadSeq:
99 ... def __getitem__(self, i):
100 ... if i >= 0 and i < 3:
101 ... return i
102 ... elif i == 3:
103 ... raise BozoError
104 ... else:
105 ... raise IndexError
106 ...
107
108 Trigger code while not expecting an IndexError (unpack sequence too long, wrong
109 error)
110
111 >>> a, b, c, d, e = BadSeq()
112 Traceback (most recent call last):
113 ...
114 test.test_unpack.BozoError
115
116 Trigger code while expecting an IndexError (unpack sequence too short, wrong
117 error)
118
119 >>> a, b, c = BadSeq()
120 Traceback (most recent call last):
121 ...
122 test.test_unpack.BozoError
123
124 Allow unpacking empty iterables
125
126 >>> () = []
127 >>> [] = ()
128 >>> [] = []
129 >>> () = ()
130
131 Unpacking non-iterables should raise TypeError
132
133 >>> () = 42
134 Traceback (most recent call last):
135 ...
136 TypeError: cannot unpack non-iterable int object
137
138 Unpacking to an empty iterable should raise ValueError
139
140 >>> () = [42]
141 Traceback (most recent call last):
142 ...
143 ValueError: too many values to unpack (expected 0)
144
145 """
146
147 __test__ = {'doctests' : doctests}
148
149 def load_tests(loader, tests, pattern):
150 tests.addTest(doctest.DocTestSuite())
151 return tests
152
153
154 class ESC[4;38;5;81mTestCornerCases(ESC[4;38;5;149munittestESC[4;38;5;149m.ESC[4;38;5;149mTestCase):
155 def test_extended_oparg_not_ignored(self):
156 # https://github.com/python/cpython/issues/91625
157 target = "(" + "y,"*400 + ")"
158 code = f"""def unpack_400(x):
159 {target} = x
160 return y
161 """
162 ns = {}
163 exec(code, ns)
164 unpack_400 = ns["unpack_400"]
165 # Warm up the function for quickening (PEP 659)
166 for _ in range(30):
167 y = unpack_400(range(400))
168 self.assertEqual(y, 399)
169
170 if __name__ == "__main__":
171 unittest.main()
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