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