summaryrefslogtreecommitdiffstats
path: root/Lib/test/test_enumerate.py
blob: 5785cb46492ef7c65a7281f24065ccae0454ae6e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
import unittest
import operator
import sys
import pickle

from test import support

class G:
    'Sequence using __getitem__'
    def __init__(self, seqn):
        self.seqn = seqn
    def __getitem__(self, i):
        return self.seqn[i]

class I:
    'Sequence using iterator protocol'
    def __init__(self, seqn):
        self.seqn = seqn
        self.i = 0
    def __iter__(self):
        return self
    def __next__(self):
        if self.i >= len(self.seqn): raise StopIteration
        v = self.seqn[self.i]
        self.i += 1
        return v

class Ig:
    'Sequence using iterator protocol defined with a generator'
    def __init__(self, seqn):
        self.seqn = seqn
        self.i = 0
    def __iter__(self):
        for val in self.seqn:
            yield val

class X:
    'Missing __getitem__ and __iter__'
    def __init__(self, seqn):
        self.seqn = seqn
        self.i = 0
    def __next__(self):
        if self.i >= len(self.seqn): raise StopIteration
        v = self.seqn[self.i]
        self.i += 1
        return v

class E:
    'Test propagation of exceptions'
    def __init__(self, seqn):
        self.seqn = seqn
        self.i = 0
    def __iter__(self):
        return self
    def __next__(self):
        3 // 0

class N:
    'Iterator missing __next__()'
    def __init__(self, seqn):
        self.seqn = seqn
        self.i = 0
    def __iter__(self):
        return self

class PickleTest:
    # Helper to check picklability
    def check_pickle(self, itorg, seq):
        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
            d = pickle.dumps(itorg, proto)
            it = pickle.loads(d)
            self.assertEqual(type(itorg), type(it))
            self.assertEqual(list(it), seq)

            it = pickle.loads(d)
            try:
                next(it)
            except StopIteration:
                self.assertFalse(seq[1:])
                continue
            d = pickle.dumps(it, proto)
            it = pickle.loads(d)
            self.assertEqual(list(it), seq[1:])

class EnumerateTestCase(unittest.TestCase, PickleTest):

    enum = enumerate
    seq, res = 'abc', [(0,'a'), (1,'b'), (2,'c')]

    def test_basicfunction(self):
        self.assertEqual(type(self.enum(self.seq)), self.enum)
        e = self.enum(self.seq)
        self.assertEqual(iter(e), e)
        self.assertEqual(list(self.enum(self.seq)), self.res)
        self.enum.__doc__

    def test_pickle(self):
        self.check_pickle(self.enum(self.seq), self.res)

    def test_getitemseqn(self):
        self.assertEqual(list(self.enum(G(self.seq))), self.res)
        e = self.enum(G(''))
        self.assertRaises(StopIteration, next, e)

    def test_iteratorseqn(self):
        self.assertEqual(list(self.enum(I(self.seq))), self.res)
        e = self.enum(I(''))
        self.assertRaises(StopIteration, next, e)

    def test_iteratorgenerator(self):
        self.assertEqual(list(self.enum(Ig(self.seq))), self.res)
        e = self.enum(Ig(''))
        self.assertRaises(StopIteration, next, e)

    def test_noniterable(self):
        self.assertRaises(TypeError, self.enum, X(self.seq))

    def test_illformediterable(self):
        self.assertRaises(TypeError, self.enum, N(self.seq))

    def test_exception_propagation(self):
        self.assertRaises(ZeroDivisionError, list, self.enum(E(self.seq)))

    def test_argumentcheck(self):
        self.assertRaises(TypeError, self.enum) # no arguments
        self.assertRaises(TypeError, self.enum, 1) # wrong type (not iterable)
        self.assertRaises(TypeError, self.enum, 'abc', 'a') # wrong type
        self.assertRaises(TypeError, self.enum, 'abc', 2, 3) # too many arguments

    @support.cpython_only
    def test_tuple_reuse(self):
        # Tests an implementation detail where tuple is reused
        # whenever nothing else holds a reference to it
        self.assertEqual(len(set(map(id, list(enumerate(self.seq))))), len(self.seq))
        self.assertEqual(len(set(map(id, enumerate(self.seq)))), min(1,len(self.seq)))

class MyEnum(enumerate):
    pass

class SubclassTestCase(EnumerateTestCase):

    enum = MyEnum

class TestEmpty(EnumerateTestCase):

    seq, res = '', []

class TestBig(EnumerateTestCase):

    seq = range(10,20000,2)
    res = list(zip(range(20000), seq))

class TestReversed(unittest.TestCase, PickleTest):

    def test_simple(self):
        class A:
            def __getitem__(self, i):
                if i < 5:
                    return str(i)
                raise StopIteration
            def __len__(self):
                return 5
        for data in ('abc', range(5), tuple(enumerate('abc')), A(),
                    range(1,17,5), dict.fromkeys('abcde')):
            self.assertEqual(list(data)[::-1], list(reversed(data)))
        # don't allow keyword arguments
        self.assertRaises(TypeError, reversed, [], a=1)

    def test_range_optimization(self):
        x = range(1)
        self.assertEqual(type(reversed(x)), type(iter(x)))

    def test_len(self):
        for s in ('hello', tuple('hello'), list('hello'), range(5)):
            self.assertEqual(operator.length_hint(reversed(s)), len(s))
            r = reversed(s)
            list(r)
            self.assertEqual(operator.length_hint(r), 0)
        class SeqWithWeirdLen:
            called = False
            def __len__(self):
                if not self.called:
                    self.called = True
                    return 10
                raise ZeroDivisionError
            def __getitem__(self, index):
                return index
        r = reversed(SeqWithWeirdLen())
        self.assertRaises(ZeroDivisionError, operator.length_hint, r)


    def test_gc(self):
        class Seq:
            def __len__(self):
                return 10
            def __getitem__(self, index):
                return index
        s = Seq()
        r = reversed(s)
        s.r = r

    def test_args(self):
        self.assertRaises(TypeError, reversed)
        self.assertRaises(TypeError, reversed, [], 'extra')

    @unittest.skipUnless(hasattr(sys, 'getrefcount'), 'test needs sys.getrefcount()')
    def test_bug1229429(self):
        # this bug was never in reversed, it was in
        # PyObject_CallMethod, and reversed_new calls that sometimes.
        def f():
            pass
        r = f.__reversed__ = object()
        rc = sys.getrefcount(r)
        for i in range(10):
            try:
                reversed(f)
            except TypeError:
                pass
            else:
                self.fail("non-callable __reversed__ didn't raise!")
        self.assertEqual(rc, sys.getrefcount(r))

    def test_objmethods(self):
        # Objects must have __len__() and __getitem__() implemented.
        class NoLen(object):
            def __getitem__(self, i): return 1
        nl = NoLen()
        self.assertRaises(TypeError, reversed, nl)

        class NoGetItem(object):
            def __len__(self): return 2
        ngi = NoGetItem()
        self.assertRaises(TypeError, reversed, ngi)

        class Blocked(object):
            def __getitem__(self, i): return 1
            def __len__(self): return 2
            __reversed__ = None
        b = Blocked()
        self.assertRaises(TypeError, reversed, b)

    def test_pickle(self):
        for data in 'abc', range(5), tuple(enumerate('abc')), range(1,17,5):
            self.check_pickle(reversed(data), list(data)[::-1])


class EnumerateStartTestCase(EnumerateTestCase):

    def test_basicfunction(self):
        e = self.enum(self.seq)
        self.assertEqual(iter(e), e)
        self.assertEqual(list(self.enum(self.seq)), self.res)


class TestStart(EnumerateStartTestCase):

    enum = lambda self, i: enumerate(i, start=11)
    seq, res = 'abc', [(11, 'a'), (12, 'b'), (13, 'c')]


class TestLongStart(EnumerateStartTestCase):

    enum = lambda self, i: enumerate(i, start=sys.maxsize+1)
    seq, res = 'abc', [(sys.maxsize+1,'a'), (sys.maxsize+2,'b'),
                       (sys.maxsize+3,'c')]


if __name__ == "__main__":
    unittest.main()