Lib/test/test_StringIO.py

   1 # Tests StringIO and cStringIO
   2
   3 import unittest
   4 import StringIO
   5 import cStringIO
   6 import types
   7 from test import test_support
   8
   9
  10 class TestGenericStringIO(unittest.TestCase):
  11     # use a class variable MODULE to define which module is being tested
  12
  13     # Line of data to test as string
  14     _line = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ!'
  15
  16     # Constructor to use for the test data (._line is passed to this
  17     # constructor)
  18     constructor = str
  19
  20     def setUp(self):
  21         self._line = self.constructor(self._line)
  22         self._lines = self.constructor((self._line + '\n') * 5)
  23         self._fp = self.MODULE.StringIO(self._lines)
  24
  25     def test_reads(self):
  26         eq = self.assertEqual
  27         eq(self._fp.read(10), self._line[:10])
  28         eq(self._fp.readline(), self._line[10:] + '\n')
  29         eq(len(self._fp.readlines(60)), 2)
  30
  31     def test_writes(self):
  32         f = self.MODULE.StringIO()
  33         f.write(self._line[:6])
  34         f.seek(3)
  35         f.write(self._line[20:26])
  36         f.write(self._line[52])
  37         self.assertEqual(f.getvalue(), 'abcuvwxyz!')
  38
  39     def test_writelines(self):
  40         f = self.MODULE.StringIO()
  41         f.writelines([self._line[0], self._line[1], self._line[2]])
  42         f.seek(0)
  43         self.assertEqual(f.getvalue(), 'abc')
  44
  45     def test_truncate(self):
  46         eq = self.assertEqual
  47         f = self.MODULE.StringIO()
  48         f.write(self._lines)
  49         f.seek(10)
  50         f.truncate()
  51         eq(f.getvalue(), 'abcdefghij')
  52         f.seek(0)
  53         f.truncate(5)
  54         eq(f.getvalue(), 'abcde')
  55         f.close()
  56         self.assertRaises(ValueError, f.write, 'frobnitz')
  57
  58     def test_iterator(self):
  59         eq = self.assertEqual
  60         unless = self.failUnless
  61         eq(iter(self._fp), self._fp)
  62         # Does this object support the iteration protocol?
  63         unless(hasattr(self._fp, '__iter__'))
  64         unless(hasattr(self._fp, 'next'))
  65         i = 0
  66         for line in self._fp:
  67             eq(line, self._line + '\n')
  68             i += 1
  69         eq(i, 5)
  70
  71 class TestStringIO(TestGenericStringIO):
  72     MODULE = StringIO
  73
  74     def test_unicode(self):
  75
  76         if not test_support.have_unicode: return
  77
  78         # The StringIO module also supports concatenating Unicode
  79         # snippets to larger Unicode strings. This is tested by this
  80         # method. Note that cStringIO does not support this extension.
  81
  82         f = self.MODULE.StringIO()
  83         f.write(self._line[:6])
  84         f.seek(3)
  85         f.write(unicode(self._line[20:26]))
  86         f.write(unicode(self._line[52]))
  87         s = f.getvalue()
  88         self.assertEqual(s, unicode('abcuvwxyz!'))
  89         self.assertEqual(type(s), types.UnicodeType)
  90
  91 class TestcStringIO(TestGenericStringIO):
  92     MODULE = cStringIO
  93
  94 import sys
  95 if sys.platform.startswith('java'):
  96     # Jython doesn't have a buffer object, so we just do a useless
  97     # fake of the buffer tests.
  98     buffer = str
  99
 100 class TestBufferStringIO(TestStringIO):
 101     constructor = buffer
 102
 103 class TestBuffercStringIO(TestcStringIO):
 104     constructor = buffer
 105
 106
 107 def test_main():
 108     test_support.run_unittest(TestStringIO)
 109     test_support.run_unittest(TestcStringIO)
 110     test_support.run_unittest(TestBufferStringIO)
 111     test_support.run_unittest(TestBuffercStringIO)
 112
 113 if __name__ == '__main__':
 114     test_main()