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