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- """Test correct operation of the print function.
- """
-
- # In 2.6, this gives us the behavior we want. In 3.0, it has
- # no function, but it still must parse correctly.
- from __future__ import print_function
-
- import unittest
- from test import test_support
-
- import sys
- if sys.version_info[0] == 3:
- # 3.x
- from io import StringIO
- else:
- # 2.x
- from StringIO import StringIO
-
- NotDefined = object()
-
- # A dispatch table all 8 combinations of providing
- # sep, end, and file
- # I use this machinery so that I'm not just passing default
- # values to print, I'm eiher passing or not passing in the
- # arguments
- dispatch = {
- (False, False, False):
- lambda args, sep, end, file: print(*args),
- (False, False, True):
- lambda args, sep, end, file: print(file=file, *args),
- (False, True, False):
- lambda args, sep, end, file: print(end=end, *args),
- (False, True, True):
- lambda args, sep, end, file: print(end=end, file=file, *args),
- (True, False, False):
- lambda args, sep, end, file: print(sep=sep, *args),
- (True, False, True):
- lambda args, sep, end, file: print(sep=sep, file=file, *args),
- (True, True, False):
- lambda args, sep, end, file: print(sep=sep, end=end, *args),
- (True, True, True):
- lambda args, sep, end, file: print(sep=sep, end=end, file=file, *args),
- }
-
- # Class used to test __str__ and print
- class ClassWith__str__:
- def __init__(self, x):
- self.x = x
- def __str__(self):
- return self.x
-
- class TestPrint(unittest.TestCase):
- def check(self, expected, args,
- sep=NotDefined, end=NotDefined, file=NotDefined):
- # Capture sys.stdout in a StringIO. Call print with args,
- # and with sep, end, and file, if they're defined. Result
- # must match expected.
-
- # Look up the actual function to call, based on if sep, end, and file
- # are defined
- fn = dispatch[(sep is not NotDefined,
- end is not NotDefined,
- file is not NotDefined)]
-
- with test_support.captured_stdout() as t:
- fn(args, sep, end, file)
-
- self.assertEqual(t.getvalue(), expected)
-
- def test_print(self):
- def x(expected, args, sep=NotDefined, end=NotDefined):
- # Run the test 2 ways: not using file, and using
- # file directed to a StringIO
-
- self.check(expected, args, sep=sep, end=end)
-
- # When writing to a file, stdout is expected to be empty
- o = StringIO()
- self.check('', args, sep=sep, end=end, file=o)
-
- # And o will contain the expected output
- self.assertEqual(o.getvalue(), expected)
-
- x('\n', ())
- x('a\n', ('a',))
- x('None\n', (None,))
- x('1 2\n', (1, 2))
- x('1 2\n', (1, ' ', 2))
- x('1*2\n', (1, 2), sep='*')
- x('1 s', (1, 's'), end='')
- x('a\nb\n', ('a', 'b'), sep='\n')
- x('1.01', (1.0, 1), sep='', end='')
- x('1*a*1.3+', (1, 'a', 1.3), sep='*', end='+')
- x('a\n\nb\n', ('a\n', 'b'), sep='\n')
- x('\0+ +\0\n', ('\0', ' ', '\0'), sep='+')
-
- x('a\n b\n', ('a\n', 'b'))
- x('a\n b\n', ('a\n', 'b'), sep=None)
- x('a\n b\n', ('a\n', 'b'), end=None)
- x('a\n b\n', ('a\n', 'b'), sep=None, end=None)
-
- x('*\n', (ClassWith__str__('*'),))
- x('abc 1\n', (ClassWith__str__('abc'), 1))
-
- # 2.x unicode tests
- x(u'1 2\n', ('1', u'2'))
- x(u'u\1234\n', (u'u\1234',))
- x(u' abc 1\n', (' ', ClassWith__str__(u'abc'), 1))
-
- # errors
- self.assertRaises(TypeError, print, '', sep=3)
- self.assertRaises(TypeError, print, '', end=3)
- self.assertRaises(AttributeError, print, '', file='')
-
- def test_main():
- test_support.run_unittest(TestPrint)
-
- if __name__ == "__main__":
- test_main()
-