AppPkg/Applications/Python/Python-2.7.2/Lib/test/test_print.py

   1 """Test correct operation of the print function.
   2 """
   3
   4 # In 2.6, this gives us the behavior we want.  In 3.0, it has
   5 #  no function, but it still must parse correctly.
   6 from __future__ import print_function
   7
   8 import unittest
   9 from test import test_support
  10
  11 from StringIO import StringIO
  12
  13 NotDefined = object()
  14
  15 # A dispatch table all 8 combinations of providing
  16 #  sep, end, and file
  17 # I use this machinery so that I'm not just passing default
  18 #  values to print, I'm either passing or not passing in the
  19 #  arguments
  20 dispatch = {
  21     (False, False, False):
  22      lambda args, sep, end, file: print(*args),
  23     (False, False, True):
  24      lambda args, sep, end, file: print(file=file, *args),
  25     (False, True,  False):
  26      lambda args, sep, end, file: print(end=end, *args),
  27     (False, True,  True):
  28      lambda args, sep, end, file: print(end=end, file=file, *args),
  29     (True,  False, False):
  30      lambda args, sep, end, file: print(sep=sep, *args),
  31     (True,  False, True):
  32      lambda args, sep, end, file: print(sep=sep, file=file, *args),
  33     (True,  True,  False):
  34      lambda args, sep, end, file: print(sep=sep, end=end, *args),
  35     (True,  True,  True):
  36      lambda args, sep, end, file: print(sep=sep, end=end, file=file, *args),
  37     }
  38
  39 # Class used to test __str__ and print
  40 class ClassWith__str__:
  41     def __init__(self, x):
  42         self.x = x
  43     def __str__(self):
  44         return self.x
  45
  46 class TestPrint(unittest.TestCase):
  47     def check(self, expected, args,
  48             sep=NotDefined, end=NotDefined, file=NotDefined):
  49         # Capture sys.stdout in a StringIO.  Call print with args,
  50         #  and with sep, end, and file, if they're defined.  Result
  51         #  must match expected.
  52
  53         # Look up the actual function to call, based on if sep, end, and file
  54         #  are defined
  55         fn = dispatch[(sep is not NotDefined,
  56                        end is not NotDefined,
  57                        file is not NotDefined)]
  58
  59         with test_support.captured_stdout() as t:
  60             fn(args, sep, end, file)
  61
  62         self.assertEqual(t.getvalue(), expected)
  63
  64     def test_print(self):
  65         def x(expected, args, sep=NotDefined, end=NotDefined):
  66             # Run the test 2 ways: not using file, and using
  67             #  file directed to a StringIO
  68
  69             self.check(expected, args, sep=sep, end=end)
  70
  71             # When writing to a file, stdout is expected to be empty
  72             o = StringIO()
  73             self.check('', args, sep=sep, end=end, file=o)
  74
  75             # And o will contain the expected output
  76             self.assertEqual(o.getvalue(), expected)
  77
  78         x('\n', ())
  79         x('a\n', ('a',))
  80         x('None\n', (None,))
  81         x('1 2\n', (1, 2))
  82         x('1   2\n', (1, ' ', 2))
  83         x('1*2\n', (1, 2), sep='*')
  84         x('1 s', (1, 's'), end='')
  85         x('a\nb\n', ('a', 'b'), sep='\n')
  86         x('1.01', (1.0, 1), sep='', end='')
  87         x('1*a*1.3+', (1, 'a', 1.3), sep='*', end='+')
  88         x('a\n\nb\n', ('a\n', 'b'), sep='\n')
  89         x('\0+ +\0\n', ('\0', ' ', '\0'), sep='+')
  90
  91         x('a\n b\n', ('a\n', 'b'))
  92         x('a\n b\n', ('a\n', 'b'), sep=None)
  93         x('a\n b\n', ('a\n', 'b'), end=None)
  94         x('a\n b\n', ('a\n', 'b'), sep=None, end=None)
  95
  96         x('*\n', (ClassWith__str__('*'),))
  97         x('abc 1\n', (ClassWith__str__('abc'), 1))
  98
  99         # 2.x unicode tests
 100         x(u'1 2\n', ('1', u'2'))
 101         x(u'u\1234\n', (u'u\1234',))
 102         x(u'  abc 1\n', (' ', ClassWith__str__(u'abc'), 1))
 103
 104         # errors
 105         self.assertRaises(TypeError, print, '', sep=3)
 106         self.assertRaises(TypeError, print, '', end=3)
 107         self.assertRaises(AttributeError, print, '', file='')
 108
 109     def test_mixed_args(self):
 110         # If an unicode arg is passed, sep and end should be unicode, too.
 111         class Recorder(object):
 112
 113             def __init__(self, must_be_unicode):
 114                 self.buf = []
 115                 self.force_unicode = must_be_unicode
 116
 117             def write(self, what):
 118                 if self.force_unicode and not isinstance(what, unicode):
 119                     raise AssertionError("{0!r} is not unicode".format(what))
 120                 self.buf.append(what)
 121
 122         buf = Recorder(True)
 123         print(u'hi', file=buf)
 124         self.assertEqual(u''.join(buf.buf), 'hi\n')
 125         del buf.buf[:]
 126         print(u'hi', u'nothing', file=buf)
 127         self.assertEqual(u''.join(buf.buf), 'hi nothing\n')
 128         buf = Recorder(False)
 129         print('hi', 'bye', end=u'\n', file=buf)
 130         self.assertIsInstance(buf.buf[1], unicode)
 131         self.assertIsInstance(buf.buf[3], unicode)
 132         del buf.buf[:]
 133         print(sep=u'x', file=buf)
 134         self.assertIsInstance(buf.buf[-1], unicode)
 135
 136
 137 def test_main():
 138     test_support.run_unittest(TestPrint)
 139
 140 if __name__ == "__main__":
 141     test_main()