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
   6 import sys
   7
   8 class SliceTest(unittest.TestCase):
   9
  10     def test_constructor(self):
  11         self.assertRaises(TypeError, slice)
  12         self.assertRaises(TypeError, slice, 1, 2, 3, 4)
  13
  14     def test_repr(self):
  15         self.assertEqual(repr(slice(1, 2, 3)), "slice(1, 2, 3)")
  16
  17     def test_hash(self):
  18         # Verify clearing of SF bug #800796
  19         self.assertRaises(TypeError, hash, slice(5))
  20         self.assertRaises(TypeError, slice(5).__hash__)
  21
  22     def test_cmp(self):
  23         s1 = slice(1, 2, 3)
  24         s2 = slice(1, 2, 3)
  25         s3 = slice(1, 2, 4)
  26         self.assertEqual(s1, s2)
  27         self.assertNotEqual(s1, s3)
  28
  29         class Exc(Exception):
  30             pass
  31
  32         class BadCmp(object):
  33             def __eq__(self, other):
  34                 raise Exc
  35
  36         s1 = slice(BadCmp())
  37         s2 = slice(BadCmp())
  38         self.assertRaises(Exc, cmp, s1, s2)
  39         self.assertEqual(s1, s1)
  40
  41         s1 = slice(1, BadCmp())
  42         s2 = slice(1, BadCmp())
  43         self.assertEqual(s1, s1)
  44         self.assertRaises(Exc, cmp, s1, s2)
  45
  46         s1 = slice(1, 2, BadCmp())
  47         s2 = slice(1, 2, BadCmp())
  48         self.assertEqual(s1, s1)
  49         self.assertRaises(Exc, cmp, s1, s2)
  50
  51     def test_members(self):
  52         s = slice(1)
  53         self.assertEqual(s.start, None)
  54         self.assertEqual(s.stop, 1)
  55         self.assertEqual(s.step, None)
  56
  57         s = slice(1, 2)
  58         self.assertEqual(s.start, 1)
  59         self.assertEqual(s.stop, 2)
  60         self.assertEqual(s.step, None)
  61
  62         s = slice(1, 2, 3)
  63         self.assertEqual(s.start, 1)
  64         self.assertEqual(s.stop, 2)
  65         self.assertEqual(s.step, 3)
  66
  67         class AnyClass:
  68             pass
  69
  70         obj = AnyClass()
  71         s = slice(obj)
  72         self.assert_(s.stop is obj)
  73
  74     def test_indices(self):
  75         self.assertEqual(slice(None           ).indices(10), (0, 10,  1))
  76         self.assertEqual(slice(None,  None,  2).indices(10), (0, 10,  2))
  77         self.assertEqual(slice(1,     None,  2).indices(10), (1, 10,  2))
  78         self.assertEqual(slice(None,  None, -1).indices(10), (9, -1, -1))
  79         self.assertEqual(slice(None,  None, -2).indices(10), (9, -1, -2))
  80         self.assertEqual(slice(3,     None, -2).indices(10), (3, -1, -2))
  81         self.assertEqual(
  82             slice(-100,  100     ).indices(10),
  83             slice(None).indices(10)
  84         )
  85         self.assertEqual(
  86             slice(100,  -100,  -1).indices(10),
  87             slice(None, None, -1).indices(10)
  88         )
  89         self.assertEqual(slice(-100L, 100L, 2L).indices(10), (0, 10,  2))
  90
  91         self.assertEqual(range(10)[::sys.maxint - 1], [0])
  92
  93         self.assertRaises(OverflowError, slice(None).indices, 1L<<100)
  94
  95 def test_main():
  96     test_support.run_unittest(SliceTest)
  97
  98 if __name__ == "__main__":
  99     test_main()