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Eric Smith799c3002008-03-18 15:35:27 +00001"""Test correct operation of the print function.
2"""
3
Christian Heimes02781dc2008-03-21 01:11:52 +00004# In 2.6, this gives us the behavior we want. In 3.0, it has
5# no function, but it still must parse correctly.
Eric Smith87824082008-03-20 23:02:08 +00006from __future__ import print_function
7
Eric Smith799c3002008-03-18 15:35:27 +00008import unittest
Benjamin Petersonee8712c2008-05-20 21:35:26 +00009from test import support
Eric Smith799c3002008-03-18 15:35:27 +000010
Eric Smith01a3e2b2008-03-18 23:48:28 +000011try:
12 # 3.x
13 from io import StringIO
14except ImportError:
15 # 2.x
16 from StringIO import StringIO
17
Eric Smith799c3002008-03-18 15:35:27 +000018NotDefined = object()
19
20# A dispatch table all 8 combinations of providing
21# sep, end, and file
22# I use this machinery so that I'm not just passing default
Ezio Melotti13925002011-03-16 11:05:33 +020023# values to print, I'm either passing or not passing in the
Eric Smith799c3002008-03-18 15:35:27 +000024# arguments
25dispatch = {
26 (False, False, False):
27 lambda args, sep, end, file: print(*args),
28 (False, False, True):
29 lambda args, sep, end, file: print(file=file, *args),
30 (False, True, False):
31 lambda args, sep, end, file: print(end=end, *args),
32 (False, True, True):
33 lambda args, sep, end, file: print(end=end, file=file, *args),
34 (True, False, False):
35 lambda args, sep, end, file: print(sep=sep, *args),
36 (True, False, True):
37 lambda args, sep, end, file: print(sep=sep, file=file, *args),
38 (True, True, False):
39 lambda args, sep, end, file: print(sep=sep, end=end, *args),
40 (True, True, True):
41 lambda args, sep, end, file: print(sep=sep, end=end, file=file, *args),
42 }
43
Eric Smith799c3002008-03-18 15:35:27 +000044# Class used to test __str__ and print
45class ClassWith__str__:
46 def __init__(self, x):
47 self.x = x
48 def __str__(self):
49 return self.x
50
51class TestPrint(unittest.TestCase):
Eric Smith01a3e2b2008-03-18 23:48:28 +000052 def check(self, expected, args,
Eric Smith799c3002008-03-18 15:35:27 +000053 sep=NotDefined, end=NotDefined, file=NotDefined):
54 # Capture sys.stdout in a StringIO. Call print with args,
55 # and with sep, end, and file, if they're defined. Result
56 # must match expected.
57
58 # Look up the actual function to call, based on if sep, end, and file
59 # are defined
60 fn = dispatch[(sep is not NotDefined,
61 end is not NotDefined,
62 file is not NotDefined)]
63
Benjamin Petersonee8712c2008-05-20 21:35:26 +000064 with support.captured_stdout() as t:
Eric Smith799c3002008-03-18 15:35:27 +000065 fn(args, sep, end, file)
66
67 self.assertEqual(t.getvalue(), expected)
68
69 def test_print(self):
Eric Smith01a3e2b2008-03-18 23:48:28 +000070 def x(expected, args, sep=NotDefined, end=NotDefined):
Eric Smith799c3002008-03-18 15:35:27 +000071 # Run the test 2 ways: not using file, and using
72 # file directed to a StringIO
73
74 self.check(expected, args, sep=sep, end=end)
75
76 # When writing to a file, stdout is expected to be empty
Eric Smith01a3e2b2008-03-18 23:48:28 +000077 o = StringIO()
Eric Smith799c3002008-03-18 15:35:27 +000078 self.check('', args, sep=sep, end=end, file=o)
79
80 # And o will contain the expected output
81 self.assertEqual(o.getvalue(), expected)
82
83 x('\n', ())
84 x('a\n', ('a',))
85 x('None\n', (None,))
86 x('1 2\n', (1, 2))
Eric Smith01a3e2b2008-03-18 23:48:28 +000087 x('1 2\n', (1, ' ', 2))
Eric Smith799c3002008-03-18 15:35:27 +000088 x('1*2\n', (1, 2), sep='*')
89 x('1 s', (1, 's'), end='')
90 x('a\nb\n', ('a', 'b'), sep='\n')
91 x('1.01', (1.0, 1), sep='', end='')
92 x('1*a*1.3+', (1, 'a', 1.3), sep='*', end='+')
Eric Smith01a3e2b2008-03-18 23:48:28 +000093 x('a\n\nb\n', ('a\n', 'b'), sep='\n')
94 x('\0+ +\0\n', ('\0', ' ', '\0'), sep='+')
95
96 x('a\n b\n', ('a\n', 'b'))
97 x('a\n b\n', ('a\n', 'b'), sep=None)
98 x('a\n b\n', ('a\n', 'b'), end=None)
99 x('a\n b\n', ('a\n', 'b'), sep=None, end=None)
Eric Smith799c3002008-03-18 15:35:27 +0000100
101 x('*\n', (ClassWith__str__('*'),))
Eric Smith01a3e2b2008-03-18 23:48:28 +0000102 x('abc 1\n', (ClassWith__str__('abc'), 1))
103
Eric Smith87824082008-03-20 23:02:08 +0000104# # 2.x unicode tests
105# x(u'1 2\n', ('1', u'2'))
106# x(u'u\1234\n', (u'u\1234',))
107# x(u' abc 1\n', (' ', ClassWith__str__(u'abc'), 1))
108
Eric Smith01a3e2b2008-03-18 23:48:28 +0000109 # errors
110 self.assertRaises(TypeError, print, '', sep=3)
111 self.assertRaises(TypeError, print, '', end=3)
112 self.assertRaises(AttributeError, print, '', file='')
Eric Smith799c3002008-03-18 15:35:27 +0000113
114def test_main():
Benjamin Petersonee8712c2008-05-20 21:35:26 +0000115 support.run_unittest(TestPrint)
Eric Smith799c3002008-03-18 15:35:27 +0000116
117if __name__ == "__main__":
118 test_main()