source: python/trunk/Lib/test/test_univnewlines2k.py

# Tests universal newline support for both reading and parsing files.
import unittest
import os
import sys
from test import test_support

if not hasattr(sys.stdin, 'newlines'):
    raise unittest.SkipTest, \
        "This Python does not have universal newline support"

FATX = 'x' * (2**14)

DATA_TEMPLATE = [
    "line1=1",
    "line2='this is a very long line designed to go past the magic " +
        "hundred character limit that is inside fileobject.c and which " +
        "is meant to speed up the common case, but we also want to test " +
        "the uncommon case, naturally.'",
    "def line3():pass",
    "line4 = '%s'" % FATX,
    ]

DATA_LF = "\n".join(DATA_TEMPLATE) + "\n"
DATA_CR = "\r".join(DATA_TEMPLATE) + "\r"
DATA_CRLF = "\r\n".join(DATA_TEMPLATE) + "\r\n"

# Note that DATA_MIXED also tests the ability to recognize a lone \r
# before end-of-file.
DATA_MIXED = "\n".join(DATA_TEMPLATE) + "\r"
DATA_SPLIT = [x + "\n" for x in DATA_TEMPLATE]
del x

class TestGenericUnivNewlines(unittest.TestCase):
    # use a class variable DATA to define the data to write to the file
    # and a class variable NEWLINE to set the expected newlines value
    READMODE = 'U'
    WRITEMODE = 'wb'

    def setUp(self):
        with open(test_support.TESTFN, self.WRITEMODE) as fp:
            fp.write(self.DATA)

    def tearDown(self):
        try:
            os.unlink(test_support.TESTFN)
        except:
            pass

    def test_read(self):
        with open(test_support.TESTFN, self.READMODE) as fp:
            data = fp.read()
        self.assertEqual(data, DATA_LF)
        self.assertEqual(repr(fp.newlines), repr(self.NEWLINE))

    def test_readlines(self):
        with open(test_support.TESTFN, self.READMODE) as fp:
            data = fp.readlines()
        self.assertEqual(data, DATA_SPLIT)
        self.assertEqual(repr(fp.newlines), repr(self.NEWLINE))

    def test_readline(self):
        with open(test_support.TESTFN, self.READMODE) as fp:
            data = []
            d = fp.readline()
            while d:
                data.append(d)
                d = fp.readline()
        self.assertEqual(data, DATA_SPLIT)
        self.assertEqual(repr(fp.newlines), repr(self.NEWLINE))

    def test_seek(self):
        with open(test_support.TESTFN, self.READMODE) as fp:
            fp.readline()
            pos = fp.tell()
            data = fp.readlines()
            self.assertEqual(data, DATA_SPLIT[1:])
            fp.seek(pos)
            data = fp.readlines()
        self.assertEqual(data, DATA_SPLIT[1:])

    def test_execfile(self):
        namespace = {}
        with test_support.check_py3k_warnings():
            execfile(test_support.TESTFN, namespace)
        func = namespace['line3']
        self.assertEqual(func.func_code.co_firstlineno, 3)
        self.assertEqual(namespace['line4'], FATX)


class TestNativeNewlines(TestGenericUnivNewlines):
    NEWLINE = None
    DATA = DATA_LF
    READMODE = 'r'
    WRITEMODE = 'w'

class TestCRNewlines(TestGenericUnivNewlines):
    NEWLINE = '\r'
    DATA = DATA_CR

class TestLFNewlines(TestGenericUnivNewlines):
    NEWLINE = '\n'
    DATA = DATA_LF

class TestCRLFNewlines(TestGenericUnivNewlines):
    NEWLINE = '\r\n'
    DATA = DATA_CRLF

    def test_tell(self):
        with open(test_support.TESTFN, self.READMODE) as fp:
            self.assertEqual(repr(fp.newlines), repr(None))
            data = fp.readline()
            pos = fp.tell()
        self.assertEqual(repr(fp.newlines), repr(self.NEWLINE))

class TestMixedNewlines(TestGenericUnivNewlines):
    NEWLINE = ('\r', '\n')
    DATA = DATA_MIXED


def test_main():
    test_support.run_unittest(
        TestNativeNewlines,
        TestCRNewlines,
        TestLFNewlines,
        TestCRLFNewlines,
        TestMixedNewlines
     )

if __name__ == '__main__':
    test_main()