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added test_print.py and marked TODOs #4778

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Merged
merged 2 commits into from
Mar 26, 2023
Merged

added test_print.py and marked TODOs #4778

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bd51ade
new test_print.py from cpython v.3.11.2
JaeyoungAhn Mar 26, 2023
074e4b3
add TODOs
JaeyoungAhn Mar 26, 2023
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240 changes: 240 additions & 0 deletions Lib/test/test_print.py
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import unittest
import sys
from io import StringIO

from test import support

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 either 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):
"""Test correct operation of the print function."""

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 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))

# errors
self.assertRaises(TypeError, print, '', sep=3)
self.assertRaises(TypeError, print, '', end=3)
self.assertRaises(AttributeError, print, '', file='')

def test_print_flush(self):
# operation of the flush flag
class filelike:
def __init__(self):
self.written = ''
self.flushed = 0

def write(self, str):
self.written += str

def flush(self):
self.flushed += 1

f = filelike()
print(1, file=f, end='', flush=True)
print(2, file=f, end='', flush=True)
print(3, file=f, flush=False)
self.assertEqual(f.written, '123\n')
self.assertEqual(f.flushed, 2)

# ensure exceptions from flush are passed through
class noflush:
def write(self, str):
pass

def flush(self):
raise RuntimeError
self.assertRaises(RuntimeError, print, 1, file=noflush(), flush=True)


class TestPy2MigrationHint(unittest.TestCase):
"""Test that correct hint is produced analogous to Python3 syntax,
if print statement is executed as in Python 2.
"""

# TODO: RUSTPYTHON
@unittest.expectedFailure
def test_normal_string(self):
python2_print_str = 'print "Hello World"'
with self.assertRaises(SyntaxError) as context:
exec(python2_print_str)

self.assertIn("Missing parentheses in call to 'print'. Did you mean print(...)",
str(context.exception))

# TODO: RUSTPYTHON
@unittest.expectedFailure
def test_string_with_soft_space(self):
python2_print_str = 'print "Hello World",'
with self.assertRaises(SyntaxError) as context:
exec(python2_print_str)

self.assertIn("Missing parentheses in call to 'print'. Did you mean print(...)",
str(context.exception))

# TODO: RUSTPYTHON
@unittest.expectedFailure
def test_string_with_excessive_whitespace(self):
python2_print_str = 'print "Hello World", '
with self.assertRaises(SyntaxError) as context:
exec(python2_print_str)

self.assertIn("Missing parentheses in call to 'print'. Did you mean print(...)",
str(context.exception))

# TODO: RUSTPYTHON
@unittest.expectedFailure
def test_string_with_leading_whitespace(self):
python2_print_str = '''if 1:
print "Hello World"
'''
with self.assertRaises(SyntaxError) as context:
exec(python2_print_str)

self.assertIn("Missing parentheses in call to 'print'. Did you mean print(...)",
str(context.exception))

# bpo-32685: Suggestions for print statement should be proper when
# it is in the same line as the header of a compound statement
# and/or followed by a semicolon

# TODO: RUSTPYTHON
@unittest.expectedFailure
def test_string_with_semicolon(self):
python2_print_str = 'print p;'
with self.assertRaises(SyntaxError) as context:
exec(python2_print_str)

self.assertIn("Missing parentheses in call to 'print'. Did you mean print(...)",
str(context.exception))

# TODO: RUSTPYTHON
@unittest.expectedFailure
def test_string_in_loop_on_same_line(self):
python2_print_str = 'for i in s: print i'
with self.assertRaises(SyntaxError) as context:
exec(python2_print_str)

self.assertIn("Missing parentheses in call to 'print'. Did you mean print(...)",
str(context.exception))

# TODO: RUSTPYTHON
@unittest.expectedFailure
def test_stream_redirection_hint_for_py2_migration(self):
# Test correct hint produced for Py2 redirection syntax
with self.assertRaises(TypeError) as context:
print >> sys.stderr, "message"
self.assertIn('Did you mean "print(<message>, '
'file=<output_stream>)"?', str(context.exception))

# Test correct hint is produced in the case where RHS implements
# __rrshift__ but returns NotImplemented
with self.assertRaises(TypeError) as context:
print >> 42
self.assertIn('Did you mean "print(<message>, '
'file=<output_stream>)"?', str(context.exception))

# Test stream redirection hint is specific to print
with self.assertRaises(TypeError) as context:
max >> sys.stderr
self.assertNotIn('Did you mean ', str(context.exception))

# Test stream redirection hint is specific to rshift
with self.assertRaises(TypeError) as context:
print << sys.stderr
self.assertNotIn('Did you mean', str(context.exception))

# Ensure right operand implementing rrshift still works
class OverrideRRShift:
def __rrshift__(self, lhs):
return 42 # Force result independent of LHS

self.assertEqual(print >> OverrideRRShift(), 42)



if __name__ == "__main__":
unittest.main()