Lib/test/test_pathlib.py

import collections
import io
import os
import errno
import pathlib
import pickle
import shutil
import socket
import stat
import sys
import tempfile
import unittest
from contextlib import contextmanager

from test import support
TESTFN = support.TESTFN

try:
    import grp, pwd
except ImportError:
    grp = pwd = None


class _BaseFlavourTest(object):

    def _check_parse_parts(self, arg, expected):
        f = self.flavour.parse_parts
        sep = self.flavour.sep
        altsep = self.flavour.altsep
        actual = f([x.replace('/', sep) for x in arg])
        self.assertEqual(actual, expected)
        if altsep:
            actual = f([x.replace('/', altsep) for x in arg])
            self.assertEqual(actual, expected)

    def test_parse_parts_common(self):
        check = self._check_parse_parts
        sep = self.flavour.sep
        # Unanchored parts
        check([],                   ('', '', []))
        check(['a'],                ('', '', ['a']))
        check(['a/'],               ('', '', ['a']))
        check(['a', 'b'],           ('', '', ['a', 'b']))
        # Expansion
        check(['a/b'],              ('', '', ['a', 'b']))
        check(['a/b/'],             ('', '', ['a', 'b']))
        check(['a', 'b/c', 'd'],    ('', '', ['a', 'b', 'c', 'd']))
        # Collapsing and stripping excess slashes
        check(['a', 'b//c', 'd'],   ('', '', ['a', 'b', 'c', 'd']))
        check(['a', 'b/c/', 'd'],   ('', '', ['a', 'b', 'c', 'd']))
        # Eliminating standalone dots
        check(['.'],                ('', '', []))
        check(['.', '.', 'b'],      ('', '', ['b']))
        check(['a', '.', 'b'],      ('', '', ['a', 'b']))
        check(['a', '.', '.'],      ('', '', ['a']))
        # The first part is anchored
        check(['/a/b'],             ('', sep, [sep, 'a', 'b']))
        check(['/a', 'b'],          ('', sep, [sep, 'a', 'b']))
        check(['/a/', 'b'],         ('', sep, [sep, 'a', 'b']))
        # Ignoring parts before an anchored part
        check(['a', '/b', 'c'],     ('', sep, [sep, 'b', 'c']))
        check(['a', '/b', '/c'],    ('', sep, [sep, 'c']))


class PosixFlavourTest(_BaseFlavourTest, unittest.TestCase):
    flavour = pathlib._posix_flavour

    def test_parse_parts(self):
        check = self._check_parse_parts
        # Collapsing of excess leading slashes, except for the double-slash
        # special case.
        check(['//a', 'b'],             ('', '//', ['//', 'a', 'b']))
        check(['///a', 'b'],            ('', '/', ['/', 'a', 'b']))
        check(['////a', 'b'],           ('', '/', ['/', 'a', 'b']))
        # Paths which look like NT paths aren't treated specially
        check(['c:a'],                  ('', '', ['c:a']))
        check(['c:\\a'],                ('', '', ['c:\\a']))
        check(['\\a'],                  ('', '', ['\\a']))

    def test_splitroot(self):
        f = self.flavour.splitroot
        self.assertEqual(f(''), ('', '', ''))
        self.assertEqual(f('a'), ('', '', 'a'))
        self.assertEqual(f('a/b'), ('', '', 'a/b'))
        self.assertEqual(f('a/b/'), ('', '', 'a/b/'))
        self.assertEqual(f('/a'), ('', '/', 'a'))
        self.assertEqual(f('/a/b'), ('', '/', 'a/b'))
        self.assertEqual(f('/a/b/'), ('', '/', 'a/b/'))
        # The root is collapsed when there are redundant slashes
        # except when there are exactly two leading slashes, which
        # is a special case in POSIX.
        self.assertEqual(f('//a'), ('', '//', 'a'))
        self.assertEqual(f('///a'), ('', '/', 'a'))
        self.assertEqual(f('///a/b'), ('', '/', 'a/b'))
        # Paths which look like NT paths aren't treated specially
        self.assertEqual(f('c:/a/b'), ('', '', 'c:/a/b'))
        self.assertEqual(f('\\/a/b'), ('', '', '\\/a/b'))
        self.assertEqual(f('\\a\\b'), ('', '', '\\a\\b'))


class NTFlavourTest(_BaseFlavourTest, unittest.TestCase):
    flavour = pathlib._windows_flavour

    def test_parse_parts(self):
        check = self._check_parse_parts
        # First part is anchored
        check(['c:'],                   ('c:', '', ['c:']))
        check(['c:\\'],                 ('c:', '\\', ['c:\\']))
        check(['\\'],                   ('', '\\', ['\\']))
        check(['c:a'],                  ('c:', '', ['c:', 'a']))
        check(['c:\\a'],                ('c:', '\\', ['c:\\', 'a']))
        check(['\\a'],                  ('', '\\', ['\\', 'a']))
        # UNC paths
        check(['\\\\a\\b'],             ('\\\\a\\b', '\\', ['\\\\a\\b\\']))
        check(['\\\\a\\b\\'],           ('\\\\a\\b', '\\', ['\\\\a\\b\\']))
        check(['\\\\a\\b\\c'],          ('\\\\a\\b', '\\', ['\\\\a\\b\\', 'c']))
        # Second part is anchored, so that the first part is ignored
        check(['a', 'Z:b', 'c'],        ('Z:', '', ['Z:', 'b', 'c']))
        check(['a', 'Z:\\b', 'c'],      ('Z:', '\\', ['Z:\\', 'b', 'c']))
        check(['a', '\\b', 'c'],        ('', '\\', ['\\', 'b', 'c']))
        # UNC paths
        check(['a', '\\\\b\\c', 'd'],   ('\\\\b\\c', '\\', ['\\\\b\\c\\', 'd']))
        # Collapsing and stripping excess slashes
        check(['a', 'Z:\\\\b\\\\c\\', 'd\\'], ('Z:', '\\', ['Z:\\', 'b', 'c', 'd']))
        # UNC paths
        check(['a', '\\\\b\\c\\\\', 'd'], ('\\\\b\\c', '\\', ['\\\\b\\c\\', 'd']))
        # Extended paths
        check(['\\\\?\\c:\\'],          ('\\\\?\\c:', '\\', ['\\\\?\\c:\\']))
        check(['\\\\?\\c:\\a'],         ('\\\\?\\c:', '\\', ['\\\\?\\c:\\', 'a']))
        # Extended UNC paths (format is "\\?\UNC\server\share")
        check(['\\\\?\\UNC\\b\\c'],     ('\\\\?\\UNC\\b\\c', '\\', ['\\\\?\\UNC\\b\\c\\']))
        check(['\\\\?\\UNC\\b\\c\\d'],  ('\\\\?\\UNC\\b\\c', '\\', ['\\\\?\\UNC\\b\\c\\', 'd']))

    def test_splitroot(self):
        f = self.flavour.splitroot
        self.assertEqual(f(''), ('', '', ''))
        self.assertEqual(f('a'), ('', '', 'a'))
        self.assertEqual(f('a\\b'), ('', '', 'a\\b'))
        self.assertEqual(f('\\a'), ('', '\\', 'a'))
        self.assertEqual(f('\\a\\b'), ('', '\\', 'a\\b'))
        self.assertEqual(f('c:a\\b'), ('c:', '', 'a\\b'))
        self.assertEqual(f('c:\\a\\b'), ('c:', '\\', 'a\\b'))
        # Redundant slashes in the root are collapsed
        self.assertEqual(f('\\\\a'), ('', '\\', 'a'))
        self.assertEqual(f('\\\\\\a/b'), ('', '\\', 'a/b'))
        self.assertEqual(f('c:\\\\a'), ('c:', '\\', 'a'))
        self.assertEqual(f('c:\\\\\\a/b'), ('c:', '\\', 'a/b'))
        # Valid UNC paths
        self.assertEqual(f('\\\\a\\b'), ('\\\\a\\b', '\\', ''))
        self.assertEqual(f('\\\\a\\b\\'), ('\\\\a\\b', '\\', ''))
        self.assertEqual(f('\\\\a\\b\\c\\d'), ('\\\\a\\b', '\\', 'c\\d'))
        # These are non-UNC paths (according to ntpath.py and test_ntpath)
        # However, command.com says such paths are invalid, so it's
        # difficult to know what the right semantics are
        self.assertEqual(f('\\\\\\a\\b'), ('', '\\', 'a\\b'))
        self.assertEqual(f('\\\\a'), ('', '\\', 'a'))


#
# Tests for the pure classes
#

class _BasePurePathTest(object):

    # keys are canonical paths, values are list of tuples of arguments
    # supposed to produce equal paths
    equivalences = {
        'a/b': [
            ('a', 'b'), ('a/', 'b'), ('a', 'b/'), ('a/', 'b/'),
            ('a/b/',), ('a//b',), ('a//b//',),
            # empty components get removed
            ('', 'a', 'b'), ('a', '', 'b'), ('a', 'b', ''),
            ],
        '/b/c/d': [
            ('a', '/b/c', 'd'), ('a', '///b//c', 'd/'),
            ('/a', '/b/c', 'd'),
            # empty components get removed
            ('/', 'b', '', 'c/d'), ('/', '', 'b/c/d'), ('', '/b/c/d'),
            ],
    }

    def setUp(self):
        p = self.cls('a')
        self.flavour = p._flavour
        self.sep = self.flavour.sep
        self.altsep = self.flavour.altsep

    def test_constructor_common(self):
        P = self.cls
        p = P('a')
        self.assertIsInstance(p, P)
        P('a', 'b', 'c')
        P('/a', 'b', 'c')
        P('a/b/c')
        P('/a/b/c')
        self.assertEqual(P(P('a')), P('a'))
        self.assertEqual(P(P('a'), 'b'), P('a/b'))
        self.assertEqual(P(P('a'), P('b')), P('a/b'))

    def test_join_common(self):
        P = self.cls
        p = P('a/b')
        pp = p.joinpath('c')
        self.assertEqual(pp, P('a/b/c'))
        self.assertIs(type(pp), type(p))
        pp = p.joinpath('c', 'd')
        self.assertEqual(pp, P('a/b/c/d'))
        pp = p.joinpath(P('c'))
        self.assertEqual(pp, P('a/b/c'))
        pp = p.joinpath('/c')
        self.assertEqual(pp, P('/c'))

    def test_div_common(self):
        # Basically the same as joinpath()
        P = self.cls
        p = P('a/b')
        pp = p / 'c'
        self.assertEqual(pp, P('a/b/c'))
        self.assertIs(type(pp), type(p))
        pp = p / 'c/d'
        self.assertEqual(pp, P('a/b/c/d'))
        pp = p / 'c' / 'd'
        self.assertEqual(pp, P('a/b/c/d'))
        pp = 'c' / p / 'd'
        self.assertEqual(pp, P('c/a/b/d'))
        pp = p / P('c')
        self.assertEqual(pp, P('a/b/c'))
        pp = p/ '/c'
        self.assertEqual(pp, P('/c'))

    def _check_str(self, expected, args):
        p = self.cls(*args)
        self.assertEqual(str(p), expected.replace('/', self.sep))

    def test_str_common(self):
        # Canonicalized paths roundtrip
        for pathstr in ('a', 'a/b', 'a/b/c', '/', '/a/b', '/a/b/c'):
            self._check_str(pathstr, (pathstr,))
        # Special case for the empty path
        self._check_str('.', ('',))
        # Other tests for str() are in test_equivalences()

    def test_as_posix_common(self):
        P = self.cls
        for pathstr in ('a', 'a/b', 'a/b/c', '/', '/a/b', '/a/b/c'):
            self.assertEqual(P(pathstr).as_posix(), pathstr)
        # Other tests for as_posix() are in test_equivalences()

    def test_as_bytes_common(self):
        sep = os.fsencode(self.sep)
        P = self.cls
        self.assertEqual(bytes(P('a/b')), b'a' + sep + b'b')

    def test_as_uri_common(self):
        P = self.cls
        with self.assertRaises(ValueError):
            P('a').as_uri()
        with self.assertRaises(ValueError):
            P().as_uri()

    def test_repr_common(self):
        for pathstr in ('a', 'a/b', 'a/b/c', '/', '/a/b', '/a/b/c'):
            p = self.cls(pathstr)
            clsname = p.__class__.__name__
            r = repr(p)
            # The repr() is in the form ClassName("forward-slashes path")
            self.assertTrue(r.startswith(clsname + '('), r)
            self.assertTrue(r.endswith(')'), r)
            inner = r[len(clsname) + 1 : -1]
            self.assertEqual(eval(inner), p.as_posix())
            # The repr() roundtrips
            q = eval(r, pathlib.__dict__)
            self.assertIs(q.__class__, p.__class__)
            self.assertEqual(q, p)
            self.assertEqual(repr(q), r)

    def test_eq_common(self):
        P = self.cls
        self.assertEqual(P('a/b'), P('a/b'))
        self.assertEqual(P('a/b'), P('a', 'b'))
        self.assertNotEqual(P('a/b'), P('a'))
        self.assertNotEqual(P('a/b'), P('/a/b'))
        self.assertNotEqual(P('a/b'), P())
        self.assertNotEqual(P('/a/b'), P('/'))
        self.assertNotEqual(P(), P('/'))
        self.assertNotEqual(P(), "")
        self.assertNotEqual(P(), {})
        self.assertNotEqual(P(), int)

    def test_match_common(self):
        P = self.cls
        self.assertRaises(ValueError, P('a').match, '')
        self.assertRaises(ValueError, P('a').match, '.')
        # Simple relative pattern
        self.assertTrue(P('b.py').match('b.py'))
        self.assertTrue(P('a/b.py').match('b.py'))
        self.assertTrue(P('/a/b.py').match('b.py'))
        self.assertFalse(P('a.py').match('b.py'))
        self.assertFalse(P('b/py').match('b.py'))
        self.assertFalse(P('/a.py').match('b.py'))
        self.assertFalse(P('b.py/c').match('b.py'))
        # Wilcard relative pattern
        self.assertTrue(P('b.py').match('*.py'))
        self.assertTrue(P('a/b.py').match('*.py'))
        self.assertTrue(P('/a/b.py').match('*.py'))
        self.assertFalse(P('b.pyc').match('*.py'))
        self.assertFalse(P('b./py').match('*.py'))
        self.assertFalse(P('b.py/c').match('*.py'))
        # Multi-part relative pattern
        self.assertTrue(P('ab/c.py').match('a*/*.py'))
        self.assertTrue(P('/d/ab/c.py').match('a*/*.py'))
        self.assertFalse(P('a.py').match('a*/*.py'))
        self.assertFalse(P('/dab/c.py').match('a*/*.py'))
        self.assertFalse(P('ab/c.py/d').match('a*/*.py'))
        # Absolute pattern
        self.assertTrue(P('/b.py').match('/*.py'))
        self.assertFalse(P('b.py').match('/*.py'))
        self.assertFalse(P('a/b.py').match('/*.py'))
        self.assertFalse(P('/a/b.py').match('/*.py'))
        # Multi-part absolute pattern
        self.assertTrue(P('/a/b.py').match('/a/*.py'))
        self.assertFalse(P('/ab.py').match('/a/*.py'))
        self.assertFalse(P('/a/b/c.py').match('/a/*.py'))

    def test_ordering_common(self):
        # Ordering is tuple-alike
        def assertLess(a, b):
            self.assertLess(a, b)
            self.assertGreater(b, a)
        P = self.cls
        a = P('a')
        b = P('a/b')
        c = P('abc')
        d = P('b')
        assertLess(a, b)
        assertLess(a, c)
        assertLess(a, d)
        assertLess(b, c)
        assertLess(c, d)
        P = self.cls
        a = P('/a')
        b = P('/a/b')
        c = P('/abc')
        d = P('/b')
        assertLess(a, b)
        assertLess(a, c)
        assertLess(a, d)
        assertLess(b, c)
        assertLess(c, d)
        with self.assertRaises(TypeError):
            P() < {}

    def test_parts_common(self):
        # `parts` returns a tuple
        sep = self.sep
        P = self.cls
        p = P('a/b')
        parts = p.parts
        self.assertEqual(parts, ('a', 'b'))
        # The object gets reused
        self.assertIs(parts, p.parts)
        # When the path is absolute, the anchor is a separate part
        p = P('/a/b')
        parts = p.parts
        self.assertEqual(parts, (sep, 'a', 'b'))

    def test_equivalences(self):
        for k, tuples in self.equivalences.items():
            canon = k.replace('/', self.sep)
            posix = k.replace(self.sep, '/')
            if canon != posix:
                tuples = tuples + [
                    tuple(part.replace('/', self.sep) for part in t)
                    for t in tuples
                    ]
                tuples.append((posix, ))
            pcanon = self.cls(canon)
            for t in tuples:
                p = self.cls(*t)
                self.assertEqual(p, pcanon, "failed with args {}".format(t))
                self.assertEqual(hash(p), hash(pcanon))
                self.assertEqual(str(p), canon)
                self.assertEqual(p.as_posix(), posix)

    def test_parent_common(self):
        # Relative
        P = self.cls
        p = P('a/b/c')
        self.assertEqual(p.parent, P('a/b'))
        self.assertEqual(p.parent.parent, P('a'))
        self.assertEqual(p.parent.parent.parent, P())
        self.assertEqual(p.parent.parent.parent.parent, P())
        # Anchored
        p = P('/a/b/c')
        self.assertEqual(p.parent, P('/a/b'))
        self.assertEqual(p.parent.parent, P('/a'))
        self.assertEqual(p.parent.parent.parent, P('/'))
        self.assertEqual(p.parent.parent.parent.parent, P('/'))

    def test_parents_common(self):
        # Relative
        P = self.cls
        p = P('a/b/c')
        par = p.parents
        self.assertEqual(len(par), 3)
        self.assertEqual(par[0], P('a/b'))
        self.assertEqual(par[1], P('a'))
        self.assertEqual(par[2], P('.'))
        self.assertEqual(list(par), [P('a/b'), P('a'), P('.')])
        with self.assertRaises(IndexError):
            par[-1]
        with self.assertRaises(IndexError):
            par[3]
        with self.assertRaises(TypeError):
            par[0] = p
        # Anchored
        p = P('/a/b/c')
        par = p.parents
        self.assertEqual(len(par), 3)
        self.assertEqual(par[0], P('/a/b'))
        self.assertEqual(par[1], P('/a'))
        self.assertEqual(par[2], P('/'))
        self.assertEqual(list(par), [P('/a/b'), P('/a'), P('/')])
        with self.assertRaises(IndexError):
            par[3]

    def test_drive_common(self):
        P = self.cls
        self.assertEqual(P('a/b').drive, '')
        self.assertEqual(P('/a/b').drive, '')
        self.assertEqual(P('').drive, '')

    def test_root_common(self):
        P = self.cls
        sep = self.sep
        self.assertEqual(P('').root, '')
        self.assertEqual(P('a/b').root, '')
        self.assertEqual(P('/').root, sep)
        self.assertEqual(P('/a/b').root, sep)

    def test_anchor_common(self):
        P = self.cls
        sep = self.sep
        self.assertEqual(P('').anchor, '')
        self.assertEqual(P('a/b').anchor, '')
        self.assertEqual(P('/').anchor, sep)
        self.assertEqual(P('/a/b').anchor, sep)

    def test_name_common(self):
        P = self.cls
        self.assertEqual(P('').name, '')
        self.assertEqual(P('.').name, '')
        self.assertEqual(P('/').name, '')
        self.assertEqual(P('a/b').name, 'b')
        self.assertEqual(P('/a/b').name, 'b')
        self.assertEqual(P('/a/b/.').name, 'b')
        self.assertEqual(P('a/b.py').name, 'b.py')
        self.assertEqual(P('/a/b.py').name, 'b.py')

    def test_suffix_common(self):
        P = self.cls
        self.assertEqual(P('').suffix, '')
        self.assertEqual(P('.').suffix, '')
        self.assertEqual(P('..').suffix, '')
        self.assertEqual(P('/').suffix, '')
        self.assertEqual(P('a/b').suffix, '')
        self.assertEqual(P('/a/b').suffix, '')
        self.assertEqual(P('/a/b/.').suffix, '')
        self.assertEqual(P('a/b.py').suffix, '.py')
        self.assertEqual(P('/a/b.py').suffix, '.py')
        self.assertEqual(P('a/.hgrc').suffix, '')
        self.assertEqual(P('/a/.hgrc').suffix, '')
        self.assertEqual(P('a/.hg.rc').suffix, '.rc')
        self.assertEqual(P('/a/.hg.rc').suffix, '.rc')
        self.assertEqual(P('a/b.tar.gz').suffix, '.gz')
        self.assertEqual(P('/a/b.tar.gz').suffix, '.gz')
        self.assertEqual(P('a/Some name. Ending with a dot.').suffix, '')
        self.assertEqual(P('/a/Some name. Ending with a dot.').suffix, '')

    def test_suffixes_common(self):
        P = self.cls
        self.assertEqual(P('').suffixes, [])
        self.assertEqual(P('.').suffixes, [])
        self.assertEqual(P('/').suffixes, [])
        self.assertEqual(P('a/b').suffixes, [])
        self.assertEqual(P('/a/b').suffixes, [])
        self.assertEqual(P('/a/b/.').suffixes, [])
        self.assertEqual(P('a/b.py').suffixes, ['.py'])
        self.assertEqual(P('/a/b.py').suffixes, ['.py'])
        self.assertEqual(P('a/.hgrc').suffixes, [])
        self.assertEqual(P('/a/.hgrc').suffixes, [])
        self.assertEqual(P('a/.hg.rc').suffixes, ['.rc'])
        self.assertEqual(P('/a/.hg.rc').suffixes, ['.rc'])
        self.assertEqual(P('a/b.tar.gz').suffixes, ['.tar', '.gz'])
        self.assertEqual(P('/a/b.tar.gz').suffixes, ['.tar', '.gz'])
        self.assertEqual(P('a/Some name. Ending with a dot.').suffixes, [])
        self.assertEqual(P('/a/Some name. Ending with a dot.').suffixes, [])

    def test_stem_common(self):
        P = self.cls
        self.assertEqual(P('').stem, '')
        self.assertEqual(P('.').stem, '')
        self.assertEqual(P('..').stem, '..')
        self.assertEqual(P('/').stem, '')
        self.assertEqual(P('a/b').stem, 'b')
        self.assertEqual(P('a/b.py').stem, 'b')
        self.assertEqual(P('a/.hgrc').stem, '.hgrc')
        self.assertEqual(P('a/.hg.rc').stem, '.hg')
        self.assertEqual(P('a/b.tar.gz').stem, 'b.tar')
        self.assertEqual(P('a/Some name. Ending with a dot.').stem,
                         'Some name. Ending with a dot.')

    def test_with_name_common(self):
        P = self.cls
        self.assertEqual(P('a/b').with_name('d.xml'), P('a/d.xml'))
        self.assertEqual(P('/a/b').with_name('d.xml'), P('/a/d.xml'))
        self.assertEqual(P('a/b.py').with_name('d.xml'), P('a/d.xml'))
        self.assertEqual(P('/a/b.py').with_name('d.xml'), P('/a/d.xml'))
        self.assertEqual(P('a/Dot ending.').with_name('d.xml'), P('a/d.xml'))
        self.assertEqual(P('/a/Dot ending.').with_name('d.xml'), P('/a/d.xml'))
        self.assertRaises(ValueError, P('').with_name, 'd.xml')
        self.assertRaises(ValueError, P('.').with_name, 'd.xml')
        self.assertRaises(ValueError, P('/').with_name, 'd.xml')

    def test_with_suffix_common(self):
        P = self.cls
        self.assertEqual(P('a/b').with_suffix('.gz'), P('a/b.gz'))
        self.assertEqual(P('/a/b').with_suffix('.gz'), P('/a/b.gz'))
        self.assertEqual(P('a/b.py').with_suffix('.gz'), P('a/b.gz'))
        self.assertEqual(P('/a/b.py').with_suffix('.gz'), P('/a/b.gz'))
        self.assertRaises(ValueError, P('').with_suffix, '.gz')
        self.assertRaises(ValueError, P('.').with_suffix, '.gz')
        self.assertRaises(ValueError, P('/').with_suffix, '.gz')

    def test_relative_to_common(self):
        P = self.cls
        p = P('a/b')
        self.assertRaises(TypeError, p.relative_to)
        self.assertEqual(p.relative_to(P()), P('a/b'))
        self.assertEqual(p.relative_to(P('a')), P('b'))
        self.assertEqual(p.relative_to(P('a/b')), P())
        # With several args
        self.assertEqual(p.relative_to('a', 'b'), P())
        # Unrelated paths
        self.assertRaises(ValueError, p.relative_to, P('c'))
        self.assertRaises(ValueError, p.relative_to, P('a/b/c'))
        self.assertRaises(ValueError, p.relative_to, P('a/c'))
        self.assertRaises(ValueError, p.relative_to, P('/a'))
        p = P('/a/b')
        self.assertEqual(p.relative_to(P('/')), P('a/b'))
        self.assertEqual(p.relative_to(P('/a')), P('b'))
        self.assertEqual(p.relative_to(P('/a/b')), P())
        # Unrelated paths
        self.assertRaises(ValueError, p.relative_to, P('/c'))
        self.assertRaises(ValueError, p.relative_to, P('/a/b/c'))
        self.assertRaises(ValueError, p.relative_to, P('/a/c'))
        self.assertRaises(ValueError, p.relative_to, P())
        self.assertRaises(ValueError, p.relative_to, P('a'))

    def test_pickling_common(self):
        P = self.cls
        p = P('/a/b')
        for proto in range(0, pickle.HIGHEST_PROTOCOL + 1):
            dumped = pickle.dumps(p, proto)
            pp = pickle.loads(dumped)
            self.assertIs(pp.__class__, p.__class__)
            self.assertEqual(pp, p)
            self.assertEqual(hash(pp), hash(p))
            self.assertEqual(str(pp), str(p))


class PurePosixPathTest(_BasePurePathTest, unittest.TestCase):
    cls = pathlib.PurePosixPath

    def test_root(self):
        P = self.cls
        self.assertEqual(P('/a/b').root, '/')
        self.assertEqual(P('///a/b').root, '/')
        # POSIX special case for two leading slashes
        self.assertEqual(P('//a/b').root, '//')

    def test_eq(self):
        P = self.cls
        self.assertNotEqual(P('a/b'), P('A/b'))
        self.assertEqual(P('/a'), P('///a'))
        self.assertNotEqual(P('/a'), P('//a'))

    def test_as_uri(self):
        P = self.cls
        self.assertEqual(P('/').as_uri(), 'file:///')
        self.assertEqual(P('/a/b.c').as_uri(), 'file:///a/b.c')
        self.assertEqual(P('/a/b%#c').as_uri(), 'file:///a/b%25%23c')

    def test_as_uri_non_ascii(self):
        from urllib.parse import quote_from_bytes
        P = self.cls
        try:
            os.fsencode('\xe9')
        except UnicodeEncodeError:
            self.skipTest("\\xe9 cannot be encoded to the filesystem encoding")
        self.assertEqual(P('/a/b\xe9').as_uri(),
                         'file:///a/b' + quote_from_bytes(os.fsencode('\xe9')))

    def test_match(self):
        P = self.cls
        self.assertFalse(P('A.py').match('a.PY'))

    def test_is_absolute(self):
        P = self.cls
        self.assertFalse(P().is_absolute())
        self.assertFalse(P('a').is_absolute())
        self.assertFalse(P('a/b/').is_absolute())
        self.assertTrue(P('/').is_absolute())
        self.assertTrue(P('/a').is_absolute())
        self.assertTrue(P('/a/b/').is_absolute())
        self.assertTrue(P('//a').is_absolute())
        self.assertTrue(P('//a/b').is_absolute())

    def test_is_reserved(self):
        P = self.cls
        self.assertIs(False, P('').is_reserved())
        self.assertIs(False, P('/').is_reserved())
        self.assertIs(False, P('/foo/bar').is_reserved())
        self.assertIs(False, P('/dev/con/PRN/NUL').is_reserved())

    def test_join(self):
        P = self.cls
        p = P('//a')
        pp = p.joinpath('b')
        self.assertEqual(pp, P('//a/b'))
        pp = P('/a').joinpath('//c')
        self.assertEqual(pp, P('//c'))
        pp = P('//a').joinpath('/c')
        self.assertEqual(pp, P('/c'))

    def test_div(self):
        # Basically the same as joinpath()
        P = self.cls
        p = P('//a')
        pp = p / 'b'
        self.assertEqual(pp, P('//a/b'))
        pp = P('/a') / '//c'
        self.assertEqual(pp, P('//c'))
        pp = P('//a') / '/c'
        self.assertEqual(pp, P('/c'))


class PureWindowsPathTest(_BasePurePathTest, unittest.TestCase):
    cls = pathlib.PureWindowsPath

    equivalences = _BasePurePathTest.equivalences.copy()
    equivalences.update({
        'c:a': [ ('c:', 'a'), ('c:', 'a/'), ('/', 'c:', 'a') ],
        'c:/a': [
            ('c:/', 'a'), ('c:', '/', 'a'), ('c:', '/a'),
            ('/z', 'c:/', 'a'), ('//x/y', 'c:/', 'a'),
            ],
        '//a/b/': [ ('//a/b',) ],
        '//a/b/c': [
            ('//a/b', 'c'), ('//a/b/', 'c'),
            ],
    })

    def test_str(self):
        p = self.cls('a/b/c')
        self.assertEqual(str(p), 'a\\b\\c')
        p = self.cls('c:/a/b/c')
        self.assertEqual(str(p), 'c:\\a\\b\\c')
        p = self.cls('//a/b')
        self.assertEqual(str(p), '\\\\a\\b\\')
        p = self.cls('//a/b/c')
        self.assertEqual(str(p), '\\\\a\\b\\c')
        p = self.cls('//a/b/c/d')
        self.assertEqual(str(p), '\\\\a\\b\\c\\d')

    def test_eq(self):
        P = self.cls
        self.assertEqual(P('c:a/b'), P('c:a/b'))
        self.assertEqual(P('c:a/b'), P('c:', 'a', 'b'))
        self.assertNotEqual(P('c:a/b'), P('d:a/b'))
        self.assertNotEqual(P('c:a/b'), P('c:/a/b'))
        self.assertNotEqual(P('/a/b'), P('c:/a/b'))
        # Case-insensitivity
        self.assertEqual(P('a/B'), P('A/b'))
        self.assertEqual(P('C:a/B'), P('c:A/b'))
        self.assertEqual(P('//Some/SHARE/a/B'), P('//somE/share/A/b'))

    def test_as_uri(self):
        from urllib.parse import quote_from_bytes
        P = self.cls
        with self.assertRaises(ValueError):
            P('/a/b').as_uri()
        with self.assertRaises(ValueError):
            P('c:a/b').as_uri()
        self.assertEqual(P('c:/').as_uri(), 'file:///c:/')
        self.assertEqual(P('c:/a/b.c').as_uri(), 'file:///c:/a/b.c')
        self.assertEqual(P('c:/a/b%#c').as_uri(), 'file:///c:/a/b%25%23c')
        self.assertEqual(P('c:/a/b\xe9').as_uri(), 'file:///c:/a/b%C3%A9')
        self.assertEqual(P('//some/share/').as_uri(), 'file://some/share/')
        self.assertEqual(P('//some/share/a/b.c').as_uri(),
                         'file://some/share/a/b.c')
        self.assertEqual(P('//some/share/a/b%#c\xe9').as_uri(),
                         'file://some/share/a/b%25%23c%C3%A9')

    def test_match_common(self):
        P = self.cls
        # Absolute patterns
        self.assertTrue(P('c:/b.py').match('/*.py'))
        self.assertTrue(P('c:/b.py').match('c:*.py'))
        self.assertTrue(P('c:/b.py').match('c:/*.py'))
        self.assertFalse(P('d:/b.py').match('c:/*.py'))  # wrong drive
        self.assertFalse(P('b.py').match('/*.py'))
        self.assertFalse(P('b.py').match('c:*.py'))
        self.assertFalse(P('b.py').match('c:/*.py'))
        self.assertFalse(P('c:b.py').match('/*.py'))
        self.assertFalse(P('c:b.py').match('c:/*.py'))
        self.assertFalse(P('/b.py').match('c:*.py'))
        self.assertFalse(P('/b.py').match('c:/*.py'))
        # UNC patterns
        self.assertTrue(P('//some/share/a.py').match('/*.py'))
        self.assertTrue(P('//some/share/a.py').match('//some/share/*.py'))
        self.assertFalse(P('//other/share/a.py').match('//some/share/*.py'))
        self.assertFalse(P('//some/share/a/b.py').match('//some/share/*.py'))
        # Case-insensitivity
        self.assertTrue(P('B.py').match('b.PY'))
        self.assertTrue(P('c:/a/B.Py').match('C:/A/*.pY'))
        self.assertTrue(P('//Some/Share/B.Py').match('//somE/sharE/*.pY'))

    def test_ordering_common(self):
        # Case-insensitivity
        def assertOrderedEqual(a, b):
            self.assertLessEqual(a, b)
            self.assertGreaterEqual(b, a)
        P = self.cls
        p = P('c:A/b')
        q = P('C:a/B')
        assertOrderedEqual(p, q)
        self.assertFalse(p < q)
        self.assertFalse(p > q)
        p = P('//some/Share/A/b')
        q = P('//Some/SHARE/a/B')
        assertOrderedEqual(p, q)
        self.assertFalse(p < q)
        self.assertFalse(p > q)

    def test_parts(self):
        P = self.cls
        p = P('c:a/b')
        parts = p.parts
        self.assertEqual(parts, ('c:', 'a', 'b'))
        p = P('c:/a/b')
        parts = p.parts
        self.assertEqual(parts, ('c:\\', 'a', 'b'))
        p = P('//a/b/c/d')
        parts = p.parts
        self.assertEqual(parts, ('\\\\a\\b\\', 'c', 'd'))

    def test_parent(self):
        # Anchored
        P = self.cls
        p = P('z:a/b/c')
        self.assertEqual(p.parent, P('z:a/b'))
        self.assertEqual(p.parent.parent, P('z:a'))
        self.assertEqual(p.parent.parent.parent, P('z:'))
        self.assertEqual(p.parent.parent.parent.parent, P('z:'))
        p = P('z:/a/b/c')
        self.assertEqual(p.parent, P('z:/a/b'))
        self.assertEqual(p.parent.parent, P('z:/a'))
        self.assertEqual(p.parent.parent.parent, P('z:/'))
        self.assertEqual(p.parent.parent.parent.parent, P('z:/'))
        p = P('//a/b/c/d')
        self.assertEqual(p.parent, P('//a/b/c'))
        self.assertEqual(p.parent.parent, P('//a/b'))
        self.assertEqual(p.parent.parent.parent, P('//a/b'))

    def test_parents(self):
        # Anchored
        P = self.cls
        p = P('z:a/b/')
        par = p.parents
        self.assertEqual(len(par), 2)
        self.assertEqual(par[0], P('z:a'))
        self.assertEqual(par[1], P('z:'))
        self.assertEqual(list(par), [P('z:a'), P('z:')])
        with self.assertRaises(IndexError):
            par[2]
        p = P('z:/a/b/')
        par = p.parents
        self.assertEqual(len(par), 2)
        self.assertEqual(par[0], P('z:/a'))
        self.assertEqual(par[1], P('z:/'))
        self.assertEqual(list(par), [P('z:/a'), P('z:/')])
        with self.assertRaises(IndexError):
            par[2]
        p = P('//a/b/c/d')
        par = p.parents
        self.assertEqual(len(par), 2)
        self.assertEqual(par[0], P('//a/b/c'))
        self.assertEqual(par[1], P('//a/b'))
        self.assertEqual(list(par), [P('//a/b/c'), P('//a/b')])
        with self.assertRaises(IndexError):
            par[2]

    def test_drive(self):
        P = self.cls
        self.assertEqual(P('c:').drive, 'c:')
        self.assertEqual(P('c:a/b').drive, 'c:')
        self.assertEqual(P('c:/').drive, 'c:')
        self.assertEqual(P('c:/a/b/').drive, 'c:')
        self.assertEqual(P('//a/b').drive, '\\\\a\\b')
        self.assertEqual(P('//a/b/').drive, '\\\\a\\b')
        self.assertEqual(P('//a/b/c/d').drive, '\\\\a\\b')

    def test_root(self):
        P = self.cls
        self.assertEqual(P('c:').root, '')
        self.assertEqual(P('c:a/b').root, '')
        self.assertEqual(P('c:/').root, '\\')
        self.assertEqual(P('c:/a/b/').root, '\\')
        self.assertEqual(P('//a/b').root, '\\')
        self.assertEqual(P('//a/b/').root, '\\')
        self.assertEqual(P('//a/b/c/d').root, '\\')

    def test_anchor(self):
        P = self.cls
        self.assertEqual(P('c:').anchor, 'c:')
        self.assertEqual(P('c:a/b').anchor, 'c:')
        self.assertEqual(P('c:/').anchor, 'c:\\')
        self.assertEqual(P('c:/a/b/').anchor, 'c:\\')
        self.assertEqual(P('//a/b').anchor, '\\\\a\\b\\')
        self.assertEqual(P('//a/b/').anchor, '\\\\a\\b\\')
        self.assertEqual(P('//a/b/c/d').anchor, '\\\\a\\b\\')

    def test_name(self):
        P = self.cls
        self.assertEqual(P('c:').name, '')
        self.assertEqual(P('c:/').name, '')
        self.assertEqual(P('c:a/b').name, 'b')
        self.assertEqual(P('c:/a/b').name, 'b')
        self.assertEqual(P('c:a/b.py').name, 'b.py')
        self.assertEqual(P('c:/a/b.py').name, 'b.py')
        self.assertEqual(P('//My.py/Share.php').name, '')
        self.assertEqual(P('//My.py/Share.php/a/b').name, 'b')

    def test_suffix(self):
        P = self.cls
        self.assertEqual(P('c:').suffix, '')
        self.assertEqual(P('c:/').suffix, '')
        self.assertEqual(P('c:a/b').suffix, '')
        self.assertEqual(P('c:/a/b').suffix, '')
        self.assertEqual(P('c:a/b.py').suffix, '.py')
        self.assertEqual(P('c:/a/b.py').suffix, '.py')
        self.assertEqual(P('c:a/.hgrc').suffix, '')
        self.assertEqual(P('c:/a/.hgrc').suffix, '')
        self.assertEqual(P('c:a/.hg.rc').suffix, '.rc')
        self.assertEqual(P('c:/a/.hg.rc').suffix, '.rc')
        self.assertEqual(P('c:a/b.tar.gz').suffix, '.gz')
        self.assertEqual(P('c:/a/b.tar.gz').suffix, '.gz')
        self.assertEqual(P('c:a/Some name. Ending with a dot.').suffix, '')
        self.assertEqual(P('c:/a/Some name. Ending with a dot.').suffix, '')
        self.assertEqual(P('//My.py/Share.php').suffix, '')
        self.assertEqual(P('//My.py/Share.php/a/b').suffix, '')

    def test_suffixes(self):
        P = self.cls
        self.assertEqual(P('c:').suffixes, [])
        self.assertEqual(P('c:/').suffixes, [])
        self.assertEqual(P('c:a/b').suffixes, [])
        self.assertEqual(P('c:/a/b').suffixes, [])
        self.assertEqual(P('c:a/b.py').suffixes, ['.py'])
        self.assertEqual(P('c:/a/b.py').suffixes, ['.py'])
        self.assertEqual(P('c:a/.hgrc').suffixes, [])
        self.assertEqual(P('c:/a/.hgrc').suffixes, [])
        self.assertEqual(P('c:a/.hg.rc').suffixes, ['.rc'])
        self.assertEqual(P('c:/a/.hg.rc').suffixes, ['.rc'])
        self.assertEqual(P('c:a/b.tar.gz').suffixes, ['.tar', '.gz'])
        self.assertEqual(P('c:/a/b.tar.gz').suffixes, ['.tar', '.gz'])
        self.assertEqual(P('//My.py/Share.php').suffixes, [])
        self.assertEqual(P('//My.py/Share.php/a/b').suffixes, [])
        self.assertEqual(P('c:a/Some name. Ending with a dot.').suffixes, [])
        self.assertEqual(P('c:/a/Some name. Ending with a dot.').suffixes, [])

    def test_stem(self):
        P = self.cls
        self.assertEqual(P('c:').stem, '')
        self.assertEqual(P('c:.').stem, '')
        self.assertEqual(P('c:..').stem, '..')
        self.assertEqual(P('c:/').stem, '')
        self.assertEqual(P('c:a/b').stem, 'b')
        self.assertEqual(P('c:a/b.py').stem, 'b')
        self.assertEqual(P('c:a/.hgrc').stem, '.hgrc')
        self.assertEqual(P('c:a/.hg.rc').stem, '.hg')
        self.assertEqual(P('c:a/b.tar.gz').stem, 'b.tar')
        self.assertEqual(P('c:a/Some name. Ending with a dot.').stem,
                         'Some name. Ending with a dot.')

    def test_with_name(self):
        P = self.cls
        self.assertEqual(P('c:a/b').with_name('d.xml'), P('c:a/d.xml'))
        self.assertEqual(P('c:/a/b').with_name('d.xml'), P('c:/a/d.xml'))
        self.assertEqual(P('c:a/Dot ending.').with_name('d.xml'), P('c:a/d.xml'))
        self.assertEqual(P('c:/a/Dot ending.').with_name('d.xml'), P('c:/a/d.xml'))
        self.assertRaises(ValueError, P('c:').with_name, 'd.xml')
        self.assertRaises(ValueError, P('c:/').with_name, 'd.xml')
        self.assertRaises(ValueError, P('//My/Share').with_name, 'd.xml')

    def test_with_suffix(self):
        P = self.cls
        self.assertEqual(P('c:a/b').with_suffix('.gz'), P('c:a/b.gz'))
        self.assertEqual(P('c:/a/b').with_suffix('.gz'), P('c:/a/b.gz'))
        self.assertEqual(P('c:a/b.py').with_suffix('.gz'), P('c:a/b.gz'))
        self.assertEqual(P('c:/a/b.py').with_suffix('.gz'), P('c:/a/b.gz'))
        self.assertRaises(ValueError, P('').with_suffix, '.gz')
        self.assertRaises(ValueError, P('.').with_suffix, '.gz')
        self.assertRaises(ValueError, P('/').with_suffix, '.gz')
        self.assertRaises(ValueError, P('//My/Share').with_suffix, '.gz')

    def test_relative_to(self):
        P = self.cls
        p = P('c:a/b')
        self.assertEqual(p.relative_to(P('c:')), P('a/b'))
        self.assertEqual(p.relative_to(P('c:a')), P('b'))
        self.assertEqual(p.relative_to(P('c:a/b')), P())
        # Unrelated paths
        self.assertRaises(ValueError, p.relative_to, P())
        self.assertRaises(ValueError, p.relative_to, P('d:'))
        self.assertRaises(ValueError, p.relative_to, P('a'))
        self.assertRaises(ValueError, p.relative_to, P('/a'))
        self.assertRaises(ValueError, p.relative_to, P('c:a/b/c'))
        self.assertRaises(ValueError, p.relative_to, P('c:a/c'))
        self.assertRaises(ValueError, p.relative_to, P('c:/a'))
        p = P('c:/a/b')
        self.assertEqual(p.relative_to(P('c:')), P('/a/b'))
        self.assertEqual(p.relative_to(P('c:/')), P('a/b'))
        self.assertEqual(p.relative_to(P('c:/a')), P('b'))
        self.assertEqual(p.relative_to(P('c:/a/b')), P())
        # Unrelated paths
        self.assertRaises(ValueError, p.relative_to, P('c:/c'))
        self.assertRaises(ValueError, p.relative_to, P('c:/a/b/c'))
        self.assertRaises(ValueError, p.relative_to, P('c:/a/c'))
        self.assertRaises(ValueError, p.relative_to, P('c:a'))
        self.assertRaises(ValueError, p.relative_to, P('d:'))
        self.assertRaises(ValueError, p.relative_to, P('d:/'))
        self.assertRaises(ValueError, p.relative_to, P('/a'))
        self.assertRaises(ValueError, p.relative_to, P('//c/a'))
        # UNC paths
        p = P('//a/b/c/d')
        self.assertEqual(p.relative_to(P('//a/b')), P('c/d'))
        self.assertEqual(p.relative_to(P('//a/b/c')), P('d'))
        self.assertEqual(p.relative_to(P('//a/b/c/d')), P())
        # Unrelated paths
        self.assertRaises(ValueError, p.relative_to, P('/a/b/c'))
        self.assertRaises(ValueError, p.relative_to, P('c:/a/b/c'))
        self.assertRaises(ValueError, p.relative_to, P('//z/b/c'))
        self.assertRaises(ValueError, p.relative_to, P('//a/z/c'))

    def test_is_absolute(self):
        P = self.cls
        # Under NT, only paths with both a drive and a root are absolute
        self.assertFalse(P().is_absolute())
        self.assertFalse(P('a').is_absolute())
        self.assertFalse(P('a/b/').is_absolute())
        self.assertFalse(P('/').is_absolute())
        self.assertFalse(P('/a').is_absolute())
        self.assertFalse(P('/a/b/').is_absolute())
        self.assertFalse(P('c:').is_absolute())
        self.assertFalse(P('c:a').is_absolute())
        self.assertFalse(P('c:a/b/').is_absolute())
        self.assertTrue(P('c:/').is_absolute())
        self.assertTrue(P('c:/a').is_absolute())
        self.assertTrue(P('c:/a/b/').is_absolute())
        # UNC paths are absolute by definition
        self.assertTrue(P('//a/b').is_absolute())
        self.assertTrue(P('//a/b/').is_absolute())
        self.assertTrue(P('//a/b/c').is_absolute())
        self.assertTrue(P('//a/b/c/d').is_absolute())

    def test_is_reserved(self):
        P = self.cls
        self.assertIs(False, P('').is_reserved())
        self.assertIs(False, P('/').is_reserved())
        self.assertIs(False, P('/foo/bar').is_reserved())
        self.assertIs(True, P('con').is_reserved())
        self.assertIs(True, P('NUL').is_reserved())
        self.assertIs(True, P('NUL.txt').is_reserved())
        self.assertIs(True, P('com1').is_reserved())
        self.assertIs(True, P('com9.bar').is_reserved())
        self.assertIs(False, P('bar.com9').is_reserved())
        self.assertIs(True, P('lpt1').is_reserved())
        self.assertIs(True, P('lpt9.bar').is_reserved())
        self.assertIs(False, P('bar.lpt9').is_reserved())
        # Only the last component matters
        self.assertIs(False, P('c:/NUL/con/baz').is_reserved())
        # UNC paths are never reserved
        self.assertIs(False, P('//my/share/nul/con/aux').is_reserved())


class PurePathTest(_BasePurePathTest, unittest.TestCase):
    cls = pathlib.PurePath

    def test_concrete_class(self):
        p = self.cls('a')
        self.assertIs(type(p),
            pathlib.PureWindowsPath if os.name == 'nt' else pathlib.PurePosixPath)

    def test_different_flavours_unequal(self):
        p = pathlib.PurePosixPath('a')
        q = pathlib.PureWindowsPath('a')
        self.assertNotEqual(p, q)

    def test_different_flavours_unordered(self):
        p = pathlib.PurePosixPath('a')
        q = pathlib.PureWindowsPath('a')
        with self.assertRaises(TypeError):
            p < q
        with self.assertRaises(TypeError):
            p <= q
        with self.assertRaises(TypeError):
            p > q
        with self.assertRaises(TypeError):
            p >= q


#
# Tests for the concrete classes
#

# Make sure any symbolic links in the base test path are resolved
BASE = os.path.realpath(TESTFN)
join = lambda *x: os.path.join(BASE, *x)
rel_join = lambda *x: os.path.join(TESTFN, *x)

def symlink_skip_reason():
    if not pathlib.supports_symlinks:
        return "no system support for symlinks"
    try:
        os.symlink(__file__, BASE)
    except OSError as e:
        return str(e)
    else:
        support.unlink(BASE)
    return None

symlink_skip_reason = symlink_skip_reason()

only_nt = unittest.skipIf(os.name != 'nt',
                          'test requires a Windows-compatible system')
only_posix = unittest.skipIf(os.name == 'nt',
                             'test requires a POSIX-compatible system')
with_symlinks = unittest.skipIf(symlink_skip_reason, symlink_skip_reason)


@only_posix
class PosixPathAsPureTest(PurePosixPathTest):
    cls = pathlib.PosixPath

@only_nt
class WindowsPathAsPureTest(PureWindowsPathTest):
    cls = pathlib.WindowsPath


class _BasePathTest(object):
    """Tests for the FS-accessing functionalities of the Path classes."""

    # (BASE)
    #  |
    #  |-- dirA/
    #       |-- linkC -> "../dirB"
    #  |-- dirB/
    #  |    |-- fileB
    #       |-- linkD -> "../dirB"
    #  |-- dirC/
    #  |    |-- fileC
    #  |    |-- fileD
    #  |-- fileA
    #  |-- linkA -> "fileA"
    #  |-- linkB -> "dirB"
    #

    def setUp(self):
        os.mkdir(BASE)
        self.addCleanup(shutil.rmtree, BASE)
        os.mkdir(join('dirA'))
        os.mkdir(join('dirB'))
        os.mkdir(join('dirC'))
        os.mkdir(join('dirC', 'dirD'))
        with open(join('fileA'), 'wb') as f:
            f.write(b"this is file A\n")
        with open(join('dirB', 'fileB'), 'wb') as f:
            f.write(b"this is file B\n")
        with open(join('dirC', 'fileC'), 'wb') as f:
            f.write(b"this is file C\n")
        with open(join('dirC', 'dirD', 'fileD'), 'wb') as f:
            f.write(b"this is file D\n")
        if not symlink_skip_reason:
            if os.name == 'nt':
                # Workaround for http://bugs.python.org/issue13772
                def dirlink(src, dest):
                    os.symlink(src, dest, target_is_directory=True)
            else:
                def dirlink(src, dest):
                    os.symlink(src, dest)
            # Relative symlinks
            os.symlink('fileA', join('linkA'))
            os.symlink('non-existing', join('brokenLink'))
            dirlink('dirB', join('linkB'))
            dirlink(os.path.join('..', 'dirB'), join('dirA', 'linkC'))
            # This one goes upwards but doesn't create a loop
            dirlink(os.path.join('..', 'dirB'), join('dirB', 'linkD'))

    def assertSame(self, path_a, path_b):
        self.assertTrue(os.path.samefile(str(path_a), str(path_b)),
                        "%r and %r don't point to the same file" %
                        (path_a, path_b))

    def assertFileNotFound(self, func, *args, **kwargs):
        with self.assertRaises(FileNotFoundError) as cm:
            func(*args, **kwargs)
        self.assertEqual(cm.exception.errno, errno.ENOENT)

    def _test_cwd(self, p):
        q = self.cls(os.getcwd())
        self.assertEqual(p, q)
        self.assertEqual(str(p), str(q))
        self.assertIs(type(p), type(q))
        self.assertTrue(p.is_absolute())

    def test_cwd(self):
        p = self.cls.cwd()
        self._test_cwd(p)

    def test_empty_path(self):
        # The empty path points to '.'
        p = self.cls('')
        self.assertEqual(p.stat(), os.stat('.'))

    def test_exists(self):
        P = self.cls
        p = P(BASE)
        self.assertIs(True, p.exists())
        self.assertIs(True, (p / 'dirA').exists())
        self.assertIs(True, (p / 'fileA').exists())
        if not symlink_skip_reason:
            self.assertIs(True, (p / 'linkA').exists())
            self.assertIs(True, (p / 'linkB').exists())
        self.assertIs(False, (p / 'foo').exists())
        self.assertIs(False, P('/xyzzy').exists())

    def test_open_common(self):
        p = self.cls(BASE)
        with (p / 'fileA').open('r') as f:
            self.assertIsInstance(f, io.TextIOBase)
            self.assertEqual(f.read(), "this is file A\n")
        with (p / 'fileA').open('rb') as f:
            self.assertIsInstance(f, io.BufferedIOBase)
            self.assertEqual(f.read().strip(), b"this is file A")
        with (p / 'fileA').open('rb', buffering=0) as f:
            self.assertIsInstance(f, io.RawIOBase)
            self.assertEqual(f.read().strip(), b"this is file A")

    def test_iterdir(self):
        P = self.cls
        p = P(BASE)
        it = p.iterdir()
        paths = set(it)
        expected = ['dirA', 'dirB', 'dirC', 'fileA']
        if not symlink_skip_reason:
            expected += ['linkA', 'linkB', 'brokenLink']
        self.assertEqual(paths, { P(BASE, q) for q in expected })

    @with_symlinks
    def test_iterdir_symlink(self):
        # __iter__ on a symlink to a directory
        P = self.cls
        p = P(BASE, 'linkB')
        paths = set(p.iterdir())
        expected = { P(BASE, 'linkB', q) for q in ['fileB', 'linkD'] }
        self.assertEqual(paths, expected)

    def test_iterdir_nodir(self):
        # __iter__ on something that is not a directory
        p = self.cls(BASE, 'fileA')
        with self.assertRaises(OSError) as cm:
            next(p.iterdir())
        # ENOENT or EINVAL under Windows, ENOTDIR otherwise
        # (see issue #12802)
        self.assertIn(cm.exception.errno, (errno.ENOTDIR,
                                           errno.ENOENT, errno.EINVAL))

    def test_glob_common(self):
        def _check(glob, expected):
            self.assertEqual(set(glob), { P(BASE, q) for q in expected })
        P = self.cls
        p = P(BASE)
        it = p.glob("fileA")
        self.assertIsInstance(it, collections.Iterator)
        _check(it, ["fileA"])
        _check(p.glob("fileB"), [])
        _check(p.glob("dir*/file*"), ["dirB/fileB", "dirC/fileC"])
        if symlink_skip_reason:
            _check(p.glob("*A"), ['dirA', 'fileA'])
        else:
            _check(p.glob("*A"), ['dirA', 'fileA', 'linkA'])
        if symlink_skip_reason:
            _check(p.glob("*B/*"), ['dirB/fileB'])
        else:
            _check(p.glob("*B/*"), ['dirB/fileB', 'dirB/linkD',
                                    'linkB/fileB', 'linkB/linkD'])
        if symlink_skip_reason:
            _check(p.glob("*/fileB"), ['dirB/fileB'])
        else:
            _check(p.glob("*/fileB"), ['dirB/fileB', 'linkB/fileB'])

    def test_rglob_common(self):
        def _check(glob, expected):
            self.assertEqual(set(glob), { P(BASE, q) for q in expected })
        P = self.cls
        p = P(BASE)
        it = p.rglob("fileA")
        self.assertIsInstance(it, collections.Iterator)
        # XXX cannot test because of symlink loops in the test setup
        #_check(it, ["fileA"])
        #_check(p.rglob("fileB"), ["dirB/fileB"])
        #_check(p.rglob("*/fileA"), [""])
        #_check(p.rglob("*/fileB"), ["dirB/fileB"])
        #_check(p.rglob("file*"), ["fileA", "dirB/fileB"])
        # No symlink loops here
        p = P(BASE, "dirC")
        _check(p.rglob("file*"), ["dirC/fileC", "dirC/dirD/fileD"])
        _check(p.rglob("*/*"), ["dirC/dirD/fileD"])

    def test_glob_dotdot(self):
        # ".." is not special in globs
        P = self.cls
        p = P(BASE)
        self.assertEqual(set(p.glob("..")), { P(BASE, "..") })
        self.assertEqual(set(p.glob("dirA/../file*")), { P(BASE, "dirA/../fileA") })
        self.assertEqual(set(p.glob("../xyzzy")), set())

    def _check_resolve_relative(self, p, expected):
        q = p.resolve()
        self.assertEqual(q, expected)

    def _check_resolve_absolute(self, p, expected):
        q = p.resolve()
        self.assertEqual(q, expected)

    @with_symlinks
    def test_resolve_common(self):
        P = self.cls
        p = P(BASE, 'foo')
        with self.assertRaises(OSError) as cm:
            p.resolve()
        self.assertEqual(cm.exception.errno, errno.ENOENT)
        # These are all relative symlinks
        p = P(BASE, 'dirB', 'fileB')
        self._check_resolve_relative(p, p)
        p = P(BASE, 'linkA')
        self._check_resolve_relative(p, P(BASE, 'fileA'))
        p = P(BASE, 'dirA', 'linkC', 'fileB')
        self._check_resolve_relative(p, P(BASE, 'dirB', 'fileB'))
        p = P(BASE, 'dirB', 'linkD', 'fileB')
        self._check_resolve_relative(p, P(BASE, 'dirB', 'fileB'))
        # Now create absolute symlinks
        d = tempfile.mkdtemp(suffix='-dirD')
        self.addCleanup(shutil.rmtree, d)
        os.symlink(os.path.join(d), join('dirA', 'linkX'))
        os.symlink(join('dirB'), os.path.join(d, 'linkY'))
        p = P(BASE, 'dirA', 'linkX', 'linkY', 'fileB')
        self._check_resolve_absolute(p, P(BASE, 'dirB', 'fileB'))

    def test_with(self):
        p = self.cls(BASE)
        it = p.iterdir()
        it2 = p.iterdir()
        next(it2)
        with p:
            pass
        # I/O operation on closed path
        self.assertRaises(ValueError, next, it)
        self.assertRaises(ValueError, next, it2)
        self.assertRaises(ValueError, p.open)
        self.assertRaises(ValueError, p.resolve)
        self.assertRaises(ValueError, p.absolute)
        self.assertRaises(ValueError, p.__enter__)

    def test_chmod(self):
        p = self.cls(BASE) / 'fileA'
        mode = p.stat().st_mode
        # Clear writable bit
        new_mode = mode & ~0o222
        p.chmod(new_mode)
        self.assertEqual(p.stat().st_mode, new_mode)
        # Set writable bit
        new_mode = mode | 0o222
        p.chmod(new_mode)
        self.assertEqual(p.stat().st_mode, new_mode)

    # XXX also need a test for lchmod

    def test_stat(self):
        p = self.cls(BASE) / 'fileA'
        st = p.stat()
        self.assertEqual(p.stat(), st)
        # Change file mode by flipping write bit
        p.chmod(st.st_mode ^ 0o222)
        self.addCleanup(p.chmod, st.st_mode)
        self.assertNotEqual(p.stat(), st)

    @with_symlinks
    def test_lstat(self):
        p = self.cls(BASE)/ 'linkA'
        st = p.stat()
        self.assertNotEqual(st, p.lstat())

    def test_lstat_nosymlink(self):
        p = self.cls(BASE) / 'fileA'
        st = p.stat()
        self.assertEqual(st, p.lstat())

    @unittest.skipUnless(pwd, "the pwd module is needed for this test")
    def test_owner(self):
        p = self.cls(BASE) / 'fileA'
        uid = p.stat().st_uid
        name = pwd.getpwuid(uid).pw_name
        self.assertEqual(name, p.owner())

    @unittest.skipUnless(grp, "the grp module is needed for this test")
    def test_group(self):
        p = self.cls(BASE) / 'fileA'
        gid = p.stat().st_gid
        name = grp.getgrgid(gid).gr_name
        self.assertEqual(name, p.group())

    def test_unlink(self):
        p = self.cls(BASE) / 'fileA'
        p.unlink()
        self.assertFileNotFound(p.stat)
        self.assertFileNotFound(p.unlink)

    def test_rmdir(self):
        p = self.cls(BASE) / 'dirA'
        for q in p.iterdir():
            q.unlink()
        p.rmdir()
        self.assertFileNotFound(p.stat)
        self.assertFileNotFound(p.unlink)

    def test_rename(self):
        P = self.cls(BASE)
        p = P / 'fileA'
        size = p.stat().st_size
        # Renaming to another path
        q = P / 'dirA' / 'fileAA'
        p.rename(q)
        self.assertEqual(q.stat().st_size, size)
        self.assertFileNotFound(p.stat)
        # Renaming to a str of a relative path
        r = rel_join('fileAAA')
        q.rename(r)
        self.assertEqual(os.stat(r).st_size, size)
        self.assertFileNotFound(q.stat)

    def test_replace(self):
        P = self.cls(BASE)
        p = P / 'fileA'
        size = p.stat().st_size
        # Replacing a non-existing path
        q = P / 'dirA' / 'fileAA'
        p.replace(q)
        self.assertEqual(q.stat().st_size, size)
        self.assertFileNotFound(p.stat)
        # Replacing another (existing) path
        r = rel_join('dirB', 'fileB')
        q.replace(r)
        self.assertEqual(os.stat(r).st_size, size)
        self.assertFileNotFound(q.stat)

    def test_touch_common(self):
        P = self.cls(BASE)
        p = P / 'newfileA'
        self.assertFalse(p.exists())
        p.touch()
        self.assertTrue(p.exists())
        old_mtime = p.stat().st_mtime
        # Rewind the mtime sufficiently far in the past to work around
        # filesystem-specific timestamp granularity.
        os.utime(str(p), (old_mtime - 10, old_mtime - 10))
        # The file mtime is refreshed by calling touch() again
        p.touch()
        self.assertGreaterEqual(p.stat().st_mtime, old_mtime)
        p = P / 'newfileB'
        self.assertFalse(p.exists())
        p.touch(mode=0o700, exist_ok=False)
        self.assertTrue(p.exists())
        self.assertRaises(OSError, p.touch, exist_ok=False)

    def test_mkdir(self):
        P = self.cls(BASE)
        p = P / 'newdirA'
        self.assertFalse(p.exists())
        p.mkdir()
        self.assertTrue(p.exists())
        self.assertTrue(p.is_dir())
        with self.assertRaises(OSError) as cm:
            p.mkdir()
        self.assertEqual(cm.exception.errno, errno.EEXIST)
        # XXX test `mode` arg

    def test_mkdir_parents(self):
        # Creating a chain of directories
        p = self.cls(BASE, 'newdirB', 'newdirC')
        self.assertFalse(p.exists())
        with self.assertRaises(OSError) as cm:
            p.mkdir()
        self.assertEqual(cm.exception.errno, errno.ENOENT)
        p.mkdir(parents=True)
        self.assertTrue(p.exists())
        self.assertTrue(p.is_dir())
        with self.assertRaises(OSError) as cm:
            p.mkdir(parents=True)
        self.assertEqual(cm.exception.errno, errno.EEXIST)
        # XXX test `mode` arg

    @with_symlinks
    def test_symlink_to(self):
        P = self.cls(BASE)
        target = P / 'fileA'
        # Symlinking a path target
        link = P / 'dirA' / 'linkAA'
        link.symlink_to(target)
        self.assertEqual(link.stat(), target.stat())
        self.assertNotEqual(link.lstat(), target.stat())
        # Symlinking a str target
        link = P / 'dirA' / 'linkAAA'
        link.symlink_to(str(target))
        self.assertEqual(link.stat(), target.stat())
        self.assertNotEqual(link.lstat(), target.stat())
        self.assertFalse(link.is_dir())
        # Symlinking to a directory
        target = P / 'dirB'
        link = P / 'dirA' / 'linkAAAA'
        link.symlink_to(target, target_is_directory=True)
        self.assertEqual(link.stat(), target.stat())
        self.assertNotEqual(link.lstat(), target.stat())
        self.assertTrue(link.is_dir())
        self.assertTrue(list(link.iterdir()))

    def test_is_dir(self):
        P = self.cls(BASE)
        self.assertTrue((P / 'dirA').is_dir())
        self.assertFalse((P / 'fileA').is_dir())
        self.assertFalse((P / 'non-existing').is_dir())
        if not symlink_skip_reason:
            self.assertFalse((P / 'linkA').is_dir())
            self.assertTrue((P / 'linkB').is_dir())
            self.assertFalse((P/ 'brokenLink').is_dir())

    def test_is_file(self):
        P = self.cls(BASE)
        self.assertTrue((P / 'fileA').is_file())
        self.assertFalse((P / 'dirA').is_file())
        self.assertFalse((P / 'non-existing').is_file())
        if not symlink_skip_reason:
            self.assertTrue((P / 'linkA').is_file())
            self.assertFalse((P / 'linkB').is_file())
            self.assertFalse((P/ 'brokenLink').is_file())

    def test_is_symlink(self):
        P = self.cls(BASE)
        self.assertFalse((P / 'fileA').is_symlink())
        self.assertFalse((P / 'dirA').is_symlink())
        self.assertFalse((P / 'non-existing').is_symlink())
        if not symlink_skip_reason:
            self.assertTrue((P / 'linkA').is_symlink())
            self.assertTrue((P / 'linkB').is_symlink())
            self.assertTrue((P/ 'brokenLink').is_symlink())

    def test_is_fifo_false(self):
        P = self.cls(BASE)
        self.assertFalse((P / 'fileA').is_fifo())
        self.assertFalse((P / 'dirA').is_fifo())
        self.assertFalse((P / 'non-existing').is_fifo())

    @unittest.skipUnless(hasattr(os, "mkfifo"), "os.mkfifo() required")
    def test_is_fifo_true(self):
        P = self.cls(BASE, 'myfifo')
        os.mkfifo(str(P))
        self.assertTrue(P.is_fifo())
        self.assertFalse(P.is_socket())
        self.assertFalse(P.is_file())

    def test_is_socket_false(self):
        P = self.cls(BASE)
        self.assertFalse((P / 'fileA').is_socket())
        self.assertFalse((P / 'dirA').is_socket())
        self.assertFalse((P / 'non-existing').is_socket())

    @unittest.skipUnless(hasattr(socket, "AF_UNIX"), "Unix sockets required")
    def test_is_socket_true(self):
        P = self.cls(BASE, 'mysock')
        sock = socket.socket(socket.SOCK_STREAM, socket.AF_UNIX)
        self.addCleanup(sock.close)
        sock.bind(str(P))
        self.assertTrue(P.is_socket())
        self.assertFalse(P.is_fifo())
        self.assertFalse(P.is_file())

    def test_is_block_device_false(self):
        P = self.cls(BASE)
        self.assertFalse((P / 'fileA').is_block_device())
        self.assertFalse((P / 'dirA').is_block_device())
        self.assertFalse((P / 'non-existing').is_block_device())

    def test_is_char_device_false(self):
        P = self.cls(BASE)
        self.assertFalse((P / 'fileA').is_char_device())
        self.assertFalse((P / 'dirA').is_char_device())
        self.assertFalse((P / 'non-existing').is_char_device())

    def test_is_char_device_true(self):
        # Under Unix, /dev/null should generally be a char device
        P = self.cls('/dev/null')
        if not P.exists():
            self.skipTest("/dev/null required")
        self.assertTrue(P.is_char_device())
        self.assertFalse(P.is_block_device())
        self.assertFalse(P.is_file())

    def test_pickling_common(self):
        p = self.cls(BASE, 'fileA')
        for proto in range(0, pickle.HIGHEST_PROTOCOL + 1):
            dumped = pickle.dumps(p, proto)
            pp = pickle.loads(dumped)
            self.assertEqual(pp.stat(), p.stat())

    def test_parts_interning(self):
        P = self.cls
        p = P('/usr/bin/foo')
        q = P('/usr/local/bin')
        # 'usr'
        self.assertIs(p.parts[1], q.parts[1])
        # 'bin'
        self.assertIs(p.parts[2], q.parts[3])


class PathTest(_BasePathTest, unittest.TestCase):
    cls = pathlib.Path

    def test_concrete_class(self):
        p = self.cls('a')
        self.assertIs(type(p),
            pathlib.WindowsPath if os.name == 'nt' else pathlib.PosixPath)

    def test_unsupported_flavour(self):
        if os.name == 'nt':
            self.assertRaises(NotImplementedError, pathlib.PosixPath)
        else:
            self.assertRaises(NotImplementedError, pathlib.WindowsPath)


@only_posix
class PosixPathTest(_BasePathTest, unittest.TestCase):
    cls = pathlib.PosixPath

    def _check_symlink_loop(self, *args):
        path = self.cls(*args)
        with self.assertRaises(RuntimeError):
            print(path.resolve())

    def test_open_mode(self):
        old_mask = os.umask(0)
        self.addCleanup(os.umask, old_mask)
        p = self.cls(BASE)
        with (p / 'new_file').open('wb'):
            pass
        st = os.stat(join('new_file'))
        self.assertEqual(stat.S_IMODE(st.st_mode), 0o666)
        os.umask(0o022)
        with (p / 'other_new_file').open('wb'):
            pass
        st = os.stat(join('other_new_file'))
        self.assertEqual(stat.S_IMODE(st.st_mode), 0o644)

    def test_touch_mode(self):
        old_mask = os.umask(0)
        self.addCleanup(os.umask, old_mask)
        p = self.cls(BASE)
        (p / 'new_file').touch()
        st = os.stat(join('new_file'))
        self.assertEqual(stat.S_IMODE(st.st_mode), 0o666)
        os.umask(0o022)
        (p / 'other_new_file').touch()
        st = os.stat(join('other_new_file'))
        self.assertEqual(stat.S_IMODE(st.st_mode), 0o644)
        (p / 'masked_new_file').touch(mode=0o750)
        st = os.stat(join('masked_new_file'))
        self.assertEqual(stat.S_IMODE(st.st_mode), 0o750)

    @with_symlinks
    def test_resolve_loop(self):
        # Loop detection for broken symlinks under POSIX
        P = self.cls
        # Loops with relative symlinks
        os.symlink('linkX/inside', join('linkX'))
        self._check_symlink_loop(BASE, 'linkX')
        os.symlink('linkY', join('linkY'))
        self._check_symlink_loop(BASE, 'linkY')
        os.symlink('linkZ/../linkZ', join('linkZ'))
        self._check_symlink_loop(BASE, 'linkZ')
        # Loops with absolute symlinks
        os.symlink(join('linkU/inside'), join('linkU'))
        self._check_symlink_loop(BASE, 'linkU')
        os.symlink(join('linkV'), join('linkV'))
        self._check_symlink_loop(BASE, 'linkV')
        os.symlink(join('linkW/../linkW'), join('linkW'))
        self._check_symlink_loop(BASE, 'linkW')

    def test_glob(self):
        P = self.cls
        p = P(BASE)
        self.assertEqual(set(p.glob("FILEa")), set())

    def test_rglob(self):
        P = self.cls
        p = P(BASE, "dirC")
        self.assertEqual(set(p.rglob("FILEd")), set())


@only_nt
class WindowsPathTest(_BasePathTest, unittest.TestCase):
    cls = pathlib.WindowsPath

    def test_glob(self):
        P = self.cls
        p = P(BASE)
        self.assertEqual(set(p.glob("FILEa")), { P(BASE, "fileA") })

    def test_rglob(self):
        P = self.cls
        p = P(BASE, "dirC")
        self.assertEqual(set(p.rglob("FILEd")), { P(BASE, "dirC/dirD/fileD") })


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