Lib/test/test_StringIO.py

   1 # Tests StringIO and cStringIO
   2
   3 import unittest
   4 import StringIO
   5 import cStringIO
   6 import types
   7 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         it = iter(self._fp)
  62         # Does this object support the iteration protocol?
  63         unless(hasattr(it, '__iter__'))
  64         unless(hasattr(it, '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 class TestcStringIO(TestGenericStringIO):
  75     MODULE = cStringIO
  76
  77 import sys
  78 if sys.platform.startswith('java'):
  79     # Jython doesn't have a buffer object, so we just do a useless
  80     # fake of the buffer tests.
  81     buffer = str
  82
  83 class TestBufferStringIO(TestStringIO):
  84     constructor = buffer
  85
  86 class TestBuffercStringIO(TestcStringIO):
  87     constructor = buffer
  88
  89
  90 def test_main():
  91     test_support.run_unittest(TestStringIO)
  92     test_support.run_unittest(TestcStringIO)
  93     test_support.run_unittest(TestBufferStringIO)
  94     test_support.run_unittest(TestBuffercStringIO)
  95
  96 if __name__ == '__main__':
  97     test_main()