Lib/test/test_slice.py

   1 # tests for slice objects; in particular the indices method.
   2
   3 import unittest
   4 from test import test_support
   5 from cPickle import loads, dumps
   6
   7 import sys
   8
   9 class SliceTest(unittest.TestCase):
  10
  11     def test_constructor(self):
  12         self.assertRaises(TypeError, slice)
  13         self.assertRaises(TypeError, slice, 1, 2, 3, 4)
  14
  15     def test_repr(self):
  16         self.assertEqual(repr(slice(1, 2, 3)), "slice(1, 2, 3)")
  17
  18     def test_hash(self):
  19         # Verify clearing of SF bug #800796
  20         self.assertRaises(TypeError, hash, slice(5))
  21         self.assertRaises(TypeError, slice(5).__hash__)
  22
  23     def test_cmp(self):
  24         s1 = slice(1, 2, 3)
  25         s2 = slice(1, 2, 3)
  26         s3 = slice(1, 2, 4)
  27         self.assertEqual(s1, s2)
  28         self.assertNotEqual(s1, s3)
  29
  30         class Exc(Exception):
  31             pass
  32
  33         class BadCmp(object):
  34             def __eq__(self, other):
  35                 raise Exc
  36             __hash__ = None # Silence Py3k warning
  37
  38         s1 = slice(BadCmp())
  39         s2 = slice(BadCmp())
  40         self.assertRaises(Exc, cmp, s1, s2)
  41         self.assertEqual(s1, s1)
  42
  43         s1 = slice(1, BadCmp())
  44         s2 = slice(1, BadCmp())
  45         self.assertEqual(s1, s1)
  46         self.assertRaises(Exc, cmp, s1, s2)
  47
  48         s1 = slice(1, 2, BadCmp())
  49         s2 = slice(1, 2, BadCmp())
  50         self.assertEqual(s1, s1)
  51         self.assertRaises(Exc, cmp, s1, s2)
  52
  53     def test_members(self):
  54         s = slice(1)
  55         self.assertEqual(s.start, None)
  56         self.assertEqual(s.stop, 1)
  57         self.assertEqual(s.step, None)
  58
  59         s = slice(1, 2)
  60         self.assertEqual(s.start, 1)
  61         self.assertEqual(s.stop, 2)
  62         self.assertEqual(s.step, None)
  63
  64         s = slice(1, 2, 3)
  65         self.assertEqual(s.start, 1)
  66         self.assertEqual(s.stop, 2)
  67         self.assertEqual(s.step, 3)
  68
  69         class AnyClass:
  70             pass
  71
  72         obj = AnyClass()
  73         s = slice(obj)
  74         self.assertTrue(s.stop is obj)
  75
  76     def test_indices(self):
  77         self.assertEqual(slice(None           ).indices(10), (0, 10,  1))
  78         self.assertEqual(slice(None,  None,  2).indices(10), (0, 10,  2))
  79         self.assertEqual(slice(1,     None,  2).indices(10), (1, 10,  2))
  80         self.assertEqual(slice(None,  None, -1).indices(10), (9, -1, -1))
  81         self.assertEqual(slice(None,  None, -2).indices(10), (9, -1, -2))
  82         self.assertEqual(slice(3,     None, -2).indices(10), (3, -1, -2))
  83         # issue 3004 tests
  84         self.assertEqual(slice(None, -9).indices(10), (0, 1, 1))
  85         self.assertEqual(slice(None, -10).indices(10), (0, 0, 1))
  86         self.assertEqual(slice(None, -11).indices(10), (0, 0, 1))
  87         self.assertEqual(slice(None, -10, -1).indices(10), (9, 0, -1))
  88         self.assertEqual(slice(None, -11, -1).indices(10), (9, -1, -1))
  89         self.assertEqual(slice(None, -12, -1).indices(10), (9, -1, -1))
  90         self.assertEqual(slice(None, 9).indices(10), (0, 9, 1))
  91         self.assertEqual(slice(None, 10).indices(10), (0, 10, 1))
  92         self.assertEqual(slice(None, 11).indices(10), (0, 10, 1))
  93         self.assertEqual(slice(None, 8, -1).indices(10), (9, 8, -1))
  94         self.assertEqual(slice(None, 9, -1).indices(10), (9, 9, -1))
  95         self.assertEqual(slice(None, 10, -1).indices(10), (9, 9, -1))
  96
  97         self.assertEqual(
  98             slice(-100,  100     ).indices(10),
  99             slice(None).indices(10)
 100         )
 101         self.assertEqual(
 102             slice(100,  -100,  -1).indices(10),
 103             slice(None, None, -1).indices(10)
 104         )
 105         self.assertEqual(slice(-100L, 100L, 2L).indices(10), (0, 10,  2))
 106
 107         self.assertEqual(range(10)[::sys.maxint - 1], [0])
 108
 109         self.assertRaises(OverflowError, slice(None).indices, 1L<<100)
 110
 111     def test_setslice_without_getslice(self):
 112         tmp = []
 113         class X(object):
 114             def __setslice__(self, i, j, k):
 115                 tmp.append((i, j, k))
 116
 117         x = X()
 118         x[1:2] = 42
 119         self.assertEquals(tmp, [(1, 2, 42)])
 120
 121     def test_pickle(self):
 122         s = slice(10, 20, 3)
 123         for protocol in (0,1,2):
 124             t = loads(dumps(s, protocol))
 125             self.assertEqual(s, t)
 126             self.assertEqual(s.indices(15), t.indices(15))
 127             self.assertNotEqual(id(s), id(t))
 128
 129 def test_main():
 130     test_support.run_unittest(SliceTest)
 131
 132 if __name__ == "__main__":
 133     test_main()