1import doctest
2import unittest
3
4
5doctests = """
6########### Tests borrowed from or inspired by test_genexps.py ############
7
8Test simple loop with conditional
9
10    >>> sum([i*i for i in range(100) if i&1 == 1])
11    166650
12
13Test simple nesting
14
15    >>> [(i,j) for i in range(3) for j in range(4)]
16    [(0, 0), (0, 1), (0, 2), (0, 3), (1, 0), (1, 1), (1, 2), (1, 3), (2, 0), (2, 1), (2, 2), (2, 3)]
17
18Test nesting with the inner expression dependent on the outer
19
20    >>> [(i,j) for i in range(4) for j in range(i)]
21    [(1, 0), (2, 0), (2, 1), (3, 0), (3, 1), (3, 2)]
22
23Test the idiom for temporary variable assignment in comprehensions.
24
25    >>> [j*j for i in range(4) for j in [i+1]]
26    [1, 4, 9, 16]
27    >>> [j*k for i in range(4) for j in [i+1] for k in [j+1]]
28    [2, 6, 12, 20]
29    >>> [j*k for i in range(4) for j, k in [(i+1, i+2)]]
30    [2, 6, 12, 20]
31
32Not assignment
33
34    >>> [i*i for i in [*range(4)]]
35    [0, 1, 4, 9]
36    >>> [i*i for i in (*range(4),)]
37    [0, 1, 4, 9]
38
39Make sure the induction variable is not exposed
40
41    >>> i = 20
42    >>> sum([i*i for i in range(100)])
43    328350
44
45    >>> i
46    20
47
48Verify that syntax error's are raised for listcomps used as lvalues
49
50    >>> [y for y in (1,2)] = 10          # doctest: +IGNORE_EXCEPTION_DETAIL
51    Traceback (most recent call last):
52       ...
53    SyntaxError: ...
54
55    >>> [y for y in (1,2)] += 10         # doctest: +IGNORE_EXCEPTION_DETAIL
56    Traceback (most recent call last):
57       ...
58    SyntaxError: ...
59
60
61########### Tests borrowed from or inspired by test_generators.py ############
62
63Make a nested list comprehension that acts like range()
64
65    >>> def frange(n):
66    ...     return [i for i in range(n)]
67    >>> frange(10)
68    [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
69
70Same again, only as a lambda expression instead of a function definition
71
72    >>> lrange = lambda n:  [i for i in range(n)]
73    >>> lrange(10)
74    [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
75
76Generators can call other generators:
77
78    >>> def grange(n):
79    ...     for x in [i for i in range(n)]:
80    ...         yield x
81    >>> list(grange(5))
82    [0, 1, 2, 3, 4]
83
84
85Make sure that None is a valid return value
86
87    >>> [None for i in range(10)]
88    [None, None, None, None, None, None, None, None, None, None]
89
90########### Tests for various scoping corner cases ############
91
92Return lambdas that use the iteration variable as a default argument
93
94    >>> items = [(lambda i=i: i) for i in range(5)]
95    >>> [x() for x in items]
96    [0, 1, 2, 3, 4]
97
98Same again, only this time as a closure variable
99
100    >>> items = [(lambda: i) for i in range(5)]
101    >>> [x() for x in items]
102    [4, 4, 4, 4, 4]
103
104Another way to test that the iteration variable is local to the list comp
105
106    >>> items = [(lambda: i) for i in range(5)]
107    >>> i = 20
108    >>> [x() for x in items]
109    [4, 4, 4, 4, 4]
110
111And confirm that a closure can jump over the list comp scope
112
113    >>> items = [(lambda: y) for i in range(5)]
114    >>> y = 2
115    >>> [x() for x in items]
116    [2, 2, 2, 2, 2]
117
118We also repeat each of the above scoping tests inside a function
119
120    >>> def test_func():
121    ...     items = [(lambda i=i: i) for i in range(5)]
122    ...     return [x() for x in items]
123    >>> test_func()
124    [0, 1, 2, 3, 4]
125
126    >>> def test_func():
127    ...     items = [(lambda: i) for i in range(5)]
128    ...     return [x() for x in items]
129    >>> test_func()
130    [4, 4, 4, 4, 4]
131
132    >>> def test_func():
133    ...     items = [(lambda: i) for i in range(5)]
134    ...     i = 20
135    ...     return [x() for x in items]
136    >>> test_func()
137    [4, 4, 4, 4, 4]
138
139    >>> def test_func():
140    ...     items = [(lambda: y) for i in range(5)]
141    ...     y = 2
142    ...     return [x() for x in items]
143    >>> test_func()
144    [2, 2, 2, 2, 2]
145
146"""
147
148
149__test__ = {'doctests' : doctests}
150
151def load_tests(loader, tests, pattern):
152    tests.addTest(doctest.DocTestSuite())
153    return tests
154
155
156if __name__ == "__main__":
157    unittest.main()
158