Issue #19673: Add pathlib to the stdlib as a provisional module (PEP 428).

8 files changed, 3830 insertions, 0 deletions

diff --git a/Doc/library/filesys.rst b/Doc/library/filesys.rst
index 58998a8..03e085b 100644
--- a/Doc/library/filesys.rst
+++ b/Doc/library/filesys.rst
@@ -12,6 +12,7 @@ in this chapter is:
 
 .. toctree::
 
+   pathlib.rst
    os.path.rst
    fileinput.rst
    stat.rst
diff --git a/Doc/library/glob.rst b/Doc/library/glob.rst
index 57ccf4a..abcbf38 100644
--- a/Doc/library/glob.rst
+++ b/Doc/library/glob.rst
@@ -25,6 +25,10 @@ For a literal match, wrap the meta-characters in brackets.
 For example, ``'[?]'`` matches the character ``'?'``.
 
 
+.. seealso::
+   The :mod:`pathlib` module offers high-level path objects.
+
+
 .. function:: glob(pathname)
 
    Return a possibly-empty list of path names that match *pathname*, which must be
diff --git a/Doc/library/os.path.rst b/Doc/library/os.path.rst
index 25cae6b..03350d7 100644
--- a/Doc/library/os.path.rst
+++ b/Doc/library/os.path.rst
@@ -22,6 +22,11 @@ Functions such as :func:`expanduser` and :func:`expandvars` can be invoked
 explicitly when an application desires shell-like path expansion.  (See also
 the :mod:`glob` module.)
 
+
+.. seealso::
+   The :mod:`pathlib` module offers high-level path objects.
+
+
 .. note::
 
    All of these functions accept either only bytes or only string objects as
diff --git a/Doc/library/pathlib.rst b/Doc/library/pathlib.rst
new file mode 100644
index 0000000..04f6c42
--- /dev/null
+++ b/Doc/library/pathlib.rst
@@ -0,0 +1,874 @@
+
+:mod:`pathlib` --- Object-oriented filesystem paths
+===================================================
+
+.. module:: pathlib
+   :synopsis: Object-oriented filesystem paths
+
+.. index:: single: path; operations
+
+.. versionadded:: 3.4
+
+
+This module offers classes representing filesystem paths with semantics
+appropriate for different operating systems.  Path classes are divided
+between :ref:`pure paths <pure-paths>`, which provide purely computational
+operations without I/O, and :ref:`concrete paths <concrete-paths>`, which
+inherit from pure paths but also provide I/O operations.
+
+The main point of entry is the :class:`Path` class, which will instantiate
+a :ref:`concrete path <concrete-paths>` for the current platform.
+
+.. note::
+   This module module has been included in the standard library on a
+   :term:`provisional basis <provisional package>`. Backwards incompatible
+   changes (up to and including removal of the package) may occur if deemed
+   necessary by the core developers.
+
+.. seealso::
+   :pep:`428`: The pathlib module -- object-oriented filesystem paths.
+
+.. seealso::
+   For low-level path manipulation on strings, you can also use the
+   :mod:`os.path` module.
+
+
+Basic use
+---------
+
+Importing the main class::
+
+   >>> from pathlib import Path
+
+Listing subdirectories::
+
+   >>> p = Path('.')
+   >>> [x for x in p.iterdir() if x.is_dir()]
+   [PosixPath('.hg'), PosixPath('docs'), PosixPath('dist'),
+    PosixPath('__pycache__'), PosixPath('build')]
+
+Listing Python source files in this directory tree::
+
+   >>> list(p.glob('**/*.py'))
+   [PosixPath('test_pathlib.py'), PosixPath('setup.py'),
+    PosixPath('pathlib.py'), PosixPath('docs/conf.py'),
+    PosixPath('build/lib/pathlib.py')]
+
+Navigating inside a directory tree::
+
+   >>> p = Path('/etc')
+   >>> q = p / 'init.d' / 'reboot'
+   >>> q
+   PosixPath('/etc/init.d/reboot')
+   >>> q.resolve()
+   PosixPath('/etc/rc.d/init.d/halt')
+
+Querying path properties::
+
+   >>> q.exists()
+   True
+   >>> q.is_dir()
+   False
+
+Opening a file::
+
+   >>> with q.open() as f: f.readline()
+   ...
+   '#!/bin/bash\n'
+
+
+.. _pure-paths:
+
+Pure paths
+----------
+
+Pure path objects provide path-handling operations which don't actually
+access a filesystem.  There are three ways to access these classes, which
+we also call *flavours*:
+
+
+.. class:: PurePosixPath
+
+   A subclass of :class:`PurePath`, this path flavour represents non-Windows
+   filesystem paths::
+
+      >>> PurePosixPath('/etc')
+      PurePosixPath('/etc')
+
+.. class:: PureWindowsPath
+
+   A subclass of :class:`PurePath`, this path flavour represents Windows
+   filesystem paths::
+
+      >>> PureWindowsPath('c:/Program Files/')
+      PureWindowsPath('c:/Program Files')
+
+.. class:: PurePath
+
+   A generic class that represents the system's path flavour (instantiating
+   it creates either a :class:`PurePosixPath` or a :class:`PureWindowsPath`)::
+
+      >>> PurePath('setup.py')
+      PurePosixPath('setup.py')
+
+
+Regardless of the system you're running on, you can instantiate all of
+these classes, since they don't provide any operation that does system calls.
+
+
+Constructing paths
+^^^^^^^^^^^^^^^^^^
+
+Path constructors accept an arbitrary number of positional arguments.
+When called without any argument, a path object points to the current
+directory::
+
+   >>> PurePath()
+   PurePosixPath('.')
+
+Any argument can be a string or bytes object representing an arbitrary number
+of path segments, but it can also be another path object::
+
+   >>> PurePath('foo', 'some/path', 'bar')
+   PurePosixPath('foo/some/path/bar')
+   >>> PurePath(Path('foo'), Path('bar'))
+   PurePosixPath('foo/bar')
+
+When several absolute paths are given, the last is taken as an anchor
+(mimicking :func:`os.path.join`'s behaviour)::
+
+   >>> PurePath('/etc', '/usr', 'lib64')
+   PurePosixPath('/usr/lib64')
+   >>> PureWindowsPath('c:/Windows', 'd:bar')
+   PureWindowsPath('d:bar')
+
+However, in a Windows path, changing the local root doesn't discard the
+previous drive setting::
+
+   >>> PureWindowsPath('c:/Windows', '/Program Files')
+   PureWindowsPath('c:/Program Files')
+
+Spurious slashes and single dots are collapsed, but double dots (``'..'``)
+are not, since this would change the meaning of a path in the face of
+symbolic links::
+
+   >>> PurePath('foo//bar')
+   PurePosixPath('foo/bar')
+   >>> PurePath('foo/./bar')
+   PurePosixPath('foo/bar')
+   >>> PurePath('foo/../bar')
+   PurePosixPath('foo/../bar')
+
+(a naïve approach would make ``PurePosixPath('foo/../bar')`` equivalent
+to ``PurePosixPath('bar')``, which is wrong if ``foo`` is a symbolic link
+to another directory)
+
+
+General properties
+^^^^^^^^^^^^^^^^^^
+
+Paths are immutable and hashable.  Paths of a same flavour are comparable
+and orderable.  These properties respect the flavour's case-folding
+semantics::
+
+   >>> PurePosixPath('foo') == PurePosixPath('FOO')
+   False
+   >>> PureWindowsPath('foo') == PureWindowsPath('FOO')
+   True
+   >>> PureWindowsPath('FOO') in { PureWindowsPath('foo') }
+   True
+   >>> PureWindowsPath('C:') < PureWindowsPath('d:')
+   True
+
+Paths of a different flavour compare unequal and cannot be ordered::
+
+   >>> PureWindowsPath('foo') == PurePosixPath('foo')
+   False
+   >>> PureWindowsPath('foo') < PurePosixPath('foo')
+   Traceback (most recent call last):
+     File "<stdin>", line 1, in <module>
+   TypeError: unorderable types: PureWindowsPath() < PurePosixPath()
+
+
+Operators
+^^^^^^^^^
+
+The slash operator helps create child paths, similarly to :func:`os.path.join`::
+
+   >>> p = PurePath('/etc')
+   >>> p
+   PurePosixPath('/etc')
+   >>> p / 'init.d' / 'apache2'
+   PurePosixPath('/etc/init.d/apache2')
+   >>> q = PurePath('bin')
+   >>> '/usr' / q
+   PurePosixPath('/usr/bin')
+
+The string representation of a path is the raw filesystem path itself
+(in native form, e.g. with backslashes under Windows), which you can
+pass to any function taking a file path as a string::
+
+   >>> p = PurePath('/etc')
+   >>> str(p)
+   '/etc'
+   >>> p = PureWindowsPath('c:/Program Files')
+   >>> str(p)
+   'c:\\Program Files'
+
+Similarly, calling :class:`bytes` on a path gives the raw filesystem path as a
+bytes object, as encoded by :func:`os.fsencode`::
+
+   >>> bytes(p)
+   b'/etc'
+
+.. note::
+   Calling :class:`bytes` is only recommended under Unix.  Under Windows,
+   the unicode form is the canonical representation of filesystem paths.
+
+
+Accessing individual parts
+^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+To access the individual "parts" (components) of a path, use the following
+property:
+
+.. data:: PurePath.parts
+
+   A tuple giving access to the path's various components::
+
+      >>> p = PurePath('/usr/bin/python3')
+      >>> p.parts
+      ('/', 'usr', 'bin', 'python3')
+
+      >>> p = PureWindowsPath('c:/Program Files/PSF')
+      >>> p.parts
+      ('c:\\', 'Program Files', 'PSF')
+
+   (note how the drive and local root are regrouped in a single part)
+
+
+Methods and properties
+^^^^^^^^^^^^^^^^^^^^^^
+
+Pure paths provide the following methods an properties:
+
+.. data:: PurePath.drive
+
+   A string representing the drive letter or name, if any::
+
+      >>> PureWindowsPath('c:/Program Files/').drive
+      'c:'
+      >>> PureWindowsPath('/Program Files/').drive
+      ''
+      >>> PurePosixPath('/etc').drive
+      ''
+
+   UNC shares are also considered drives::
+
+      >>> PureWindowsPath('//host/share/foo.txt').drive
+      '\\\\host\\share'
+
+.. data:: PurePath.root
+
+   A string representing the (local or global) root, if any::
+
+      >>> PureWindowsPath('c:/Program Files/').root
+      '\\'
+      >>> PureWindowsPath('c:Program Files/').root
+      ''
+      >>> PurePosixPath('/etc').root
+      '/'
+
+   UNC shares always have a root::
+
+      >>> PureWindowsPath('//host/share').root
+      '\\'
+
+.. data:: PurePath.anchor
+
+   The concatenation of the drive and root::
+
+      >>> PureWindowsPath('c:/Program Files/').anchor
+      'c:\\'
+      >>> PureWindowsPath('c:Program Files/').anchor
+      'c:'
+      >>> PurePosixPath('/etc').anchor
+      '/'
+      >>> PureWindowsPath('//host/share').anchor
+      '\\\\host\\share\\'
+
+
+.. data:: PurePath.parents
+
+   An immutable sequence providing access to the logical ancestors of
+   the path::
+
+      >>> p = PureWindowsPath('c:/foo/bar/setup.py')
+      >>> p.parents[0]
+      PureWindowsPath('c:/foo/bar')
+      >>> p.parents[1]
+      PureWindowsPath('c:/foo')
+      >>> p.parents[2]
+      PureWindowsPath('c:/')
+
+
+.. data:: PurePath.parent
+
+   The logical parent of the path::
+
+      >>> p = PurePosixPath('/a/b/c/d')
+      >>> p.parent
+      PurePosixPath('/a/b/c')
+
+   You cannot go past an anchor, or empty path::
+
+      >>> p = PurePosixPath('/')
+      >>> p.parent
+      PurePosixPath('/')
+      >>> p = PurePosixPath('.')
+      >>> p.parent
+      PurePosixPath('.')
+
+   .. note::
+      This is a purely lexical operation, hence the following behaviour::
+
+         >>> p = PurePosixPath('foo/..')
+         >>> p.parent
+         PurePosixPath('foo')
+
+      If you want to walk an arbitrary filesystem path upwards, it is
+      recommended to first call :meth:`Path.resolve` so as to resolve
+      symlinks and eliminate `".."` components.
+
+
+.. data:: PurePath.name
+
+   A string representing the final path component, excluding the drive and
+   root, if any::
+
+      >>> PurePosixPath('my/library/setup.py').name
+      'setup.py'
+
+   UNC drive names are not considered::
+
+      >>> PureWindowsPath('//some/share/setup.py').name
+      'setup.py'
+      >>> PureWindowsPath('//some/share').name
+      ''
+
+
+.. data:: PurePath.suffix
+
+   The file extension of the final component, if any::
+
+      >>> PurePosixPath('my/library/setup.py').suffix
+      '.py'
+      >>> PurePosixPath('my/library.tar.gz').suffix
+      '.gz'
+      >>> PurePosixPath('my/library').suffix
+      ''
+
+
+.. data:: PurePath.suffixes
+
+   A list of the path's file extensions::
+
+      >>> PurePosixPath('my/library.tar.gar').suffixes
+      ['.tar', '.gar']
+      >>> PurePosixPath('my/library.tar.gz').suffixes
+      ['.tar', '.gz']
+      >>> PurePosixPath('my/library').suffixes
+      []
+
+
+.. data:: PurePath.stem
+
+   The final path component, without its suffix::
+
+      >>> PurePosixPath('my/library.tar.gz').stem
+      'library.tar'
+      >>> PurePosixPath('my/library.tar').stem
+      'library'
+      >>> PurePosixPath('my/library').stem
+      'library'
+
+
+.. method:: PurePath.as_posix()
+
+   Return a string representation of the path with forward slashes (``/``)::
+
+      >>> p = PureWindowsPath('c:\\windows')
+      >>> str(p)
+      'c:\\windows'
+      >>> p.as_posix()
+      'c:/windows'
+
+
+.. method:: PurePath.as_uri()
+
+   Represent the path as a ``file`` URI.  :exc:`ValueError` is raised if
+   the path isn't absolute.
+
+      >>> p = PurePosixPath('/etc/passwd')
+      >>> p.as_uri()
+      'file:///etc/passwd'
+      >>> p = PureWindowsPath('c:/Windows')
+      >>> p.as_uri()
+      'file:///c:/Windows'
+
+
+.. method:: PurePath.is_absolute()
+
+   Return whether the path is absolute or not.  A path is considered absolute
+   if it has both a root and (if the flavour allows) a drive::
+
+      >>> PurePosixPath('/a/b').is_absolute()
+      True
+      >>> PurePosixPath('a/b').is_absolute()
+      False
+
+      >>> PureWindowsPath('c:/a/b').is_absolute()
+      True
+      >>> PureWindowsPath('/a/b').is_absolute()
+      False
+      >>> PureWindowsPath('c:').is_absolute()
+      False
+      >>> PureWindowsPath('//some/share').is_absolute()
+      True
+
+
+.. method:: PurePath.is_reserved()
+
+   With :class:`PureWindowsPath`, return True if the path is considered
+   reserved under Windows, False otherwise.  With :class:`PurePosixPath`,
+   False is always returned.
+
+      >>> PureWindowsPath('nul').is_reserved()
+      True
+      >>> PurePosixPath('nul').is_reserved()
+      False
+
+   File system calls on reserved paths can fail mysteriously or have
+   unintended effects.
+
+
+.. method:: PurePath.joinpath(*other)
+
+   Calling this method is equivalent to indexing the path with each of
+   the *other* arguments in turn::
+
+      >>> PurePosixPath('/etc').joinpath('passwd')
+      PurePosixPath('/etc/passwd')
+      >>> PurePosixPath('/etc').joinpath(PurePosixPath('passwd'))
+      PurePosixPath('/etc/passwd')
+      >>> PurePosixPath('/etc').joinpath('init.d', 'apache2')
+      PurePosixPath('/etc/init.d/apache2')
+      >>> PureWindowsPath('c:').joinpath('/Program Files')
+      PureWindowsPath('c:/Program Files')
+
+
+.. method:: PurePath.match(pattern)
+
+   Match this path against the provided glob-style pattern.  Return True
+   if matching is successful, False otherwise.
+
+   If *pattern* is relative, the path can be either relative or absolute,
+   and matching is done from the right::
+
+      >>> PurePath('a/b.py').match('*.py')
+      True
+      >>> PurePath('/a/b/c.py').match('b/*.py')
+      True
+      >>> PurePath('/a/b/c.py').match('a/*.py')
+      False
+
+   If *pattern* is absolute, the path must be absolute, and the whole path
+   must match::
+
+      >>> PurePath('/a.py').match('/*.py')
+      True
+      >>> PurePath('a/b.py').match('/*.py')
+      False
+
+   As with other methods, case-sensitivity is observed::
+
+      >>> PureWindowsPath('b.py').match('*.PY')
+      True
+
+
+.. method:: PurePath.relative_to(*other)
+
+   Compute a version of this path relative to the path represented by
+   *other*.  If it's impossible, ValueError is raised::
+
+      >>> p = PurePosixPath('/etc/passwd')
+      >>> p.relative_to('/')
+      PurePosixPath('etc/passwd')
+      >>> p.relative_to('/etc')
+      PurePosixPath('passwd')
+      >>> p.relative_to('/usr')
+      Traceback (most recent call last):
+        File "<stdin>", line 1, in <module>
+        File "pathlib.py", line 694, in relative_to
+          .format(str(self), str(formatted)))
+      ValueError: '/etc/passwd' does not start with '/usr'
+
+
+.. _concrete-paths:
+
+
+Concrete paths
+--------------
+
+Concrete paths are subclasses of the pure path classes.  In addition to
+operations provided by the latter, they also provide methods to do system
+calls on path objects.  There are three ways to instantiate concrete paths:
+
+
+.. class:: PosixPath
+
+   A subclass of :class:`Path` and :class:`PurePosixPath`, this class
+   represents concrete non-Windows filesystem paths::
+
+      >>> PosixPath('/etc')
+      PosixPath('/etc')
+
+.. class:: WindowsPath
+
+   A subclass of :class:`Path` and :class:`PureWindowsPath`, this class
+   represents concrete Windows filesystem paths::
+
+      >>> WindowsPath('c:/Program Files/')
+      WindowsPath('c:/Program Files')
+
+.. class:: Path
+
+   A subclass of :class:`PurePath`, this class represents concrete paths of
+   the system's path flavour (instantiating it creates either a
+   :class:`PosixPath` or a :class:`WindowsPath`)::
+
+      >>> Path('setup.py')
+      PosixPath('setup.py')
+
+
+You can only instantiate the class flavour that corresponds to your system
+(allowing system calls on non-compatible path flavours could lead to
+bugs or failures in your application)::
+
+   >>> import os
+   >>> os.name
+   'posix'
+   >>> Path('setup.py')
+   PosixPath('setup.py')
+   >>> PosixPath('setup.py')
+   PosixPath('setup.py')
+   >>> WindowsPath('setup.py')
+   Traceback (most recent call last):
+     File "<stdin>", line 1, in <module>
+     File "pathlib.py", line 798, in __new__
+       % (cls.__name__,))
+   NotImplementedError: cannot instantiate 'WindowsPath' on your system
+
+
+Methods
+^^^^^^^
+
+Concrete paths provide the following methods in addition to pure paths
+methods.  Many of these methods can raise an :exc:`OSError` if a system
+call fails (for example because the path doesn't exist):
+
+.. classmethod:: Path.cwd()
+
+   Return a new path object representing the current directory (as returned
+   by :func:`os.getcwd`)::
+
+      >>> Path.cwd()
+      PosixPath('/home/antoine/pathlib')
+
+
+.. method:: Path.stat()
+
+   Return information about this path (similarly to :func:`os.stat`).
+   The result is looked up at each call to this method.
+
+      >>> p = Path('setup.py')
+      >>> p.stat().st_size
+      956
+      >>> p.stat().st_mtime
+      1327883547.852554
+
+
+.. method:: Path.chmod(mode)
+
+   Change the file mode and permissions, like :func:`os.chmod`::
+
+      >>> p = Path('setup.py')
+      >>> p.stat().st_mode
+      33277
+      >>> p.chmod(0o444)
+      >>> p.stat().st_mode
+      33060
+
+
+.. method:: Path.exists()
+
+   Whether the path points to an existing file or directory::
+
+      >>> Path('.').exists()
+      True
+      >>> Path('setup.py').exists()
+      True
+      >>> Path('/etc').exists()
+      True
+      >>> Path('nonexistentfile').exists()
+      False
+
+   .. note::
+      If the path points to a symlink, :meth:`exists` returns whether the
+      symlink *points to* an existing file or directory.
+
+
+.. method:: Path.glob(pattern)
+
+   Glob the given *pattern* in the directory represented by this path,
+   yielding all matching files (of any kind)::
+
+      >>> sorted(Path('.').glob('*.py'))
+      [PosixPath('pathlib.py'), PosixPath('setup.py'), PosixPath('test_pathlib.py')]
+      >>> sorted(Path('.').glob('*/*.py'))
+      [PosixPath('docs/conf.py')]
+
+   The "``**``" pattern means "this directory and all subdirectories,
+   recursively".  In other words, it enables recursive globbing::
+
+      >>> sorted(Path('.').glob('**/*.py'))
+      [PosixPath('build/lib/pathlib.py'),
+       PosixPath('docs/conf.py'),
+       PosixPath('pathlib.py'),
+       PosixPath('setup.py'),
+       PosixPath('test_pathlib.py')]
+
+   .. note::
+      Using the "``**``" pattern in large directory trees may consume
+      an inordinate amount of time.
+
+
+.. method:: Path.group()
+
+   Return the name of the group owning the file.  :exc:`KeyError` is thrown
+   if the file's gid isn't found in the system database.
+
+
+.. method:: Path.is_dir()
+
+   Return True if the path points to a directory (or a symbolic link
+   pointing to a directory), False if it points to another kind of file.
+
+   False is also returned if the path doesn't exist or is a broken symlink;
+   other errors (such as permission errors) are propagated.
+
+
+.. method:: Path.is_file()
+
+   Return True if the path points to a regular file (or a symbolic link
+   pointing to a regular file), False if it points to another kind of file.
+
+   False is also returned if the path doesn't exist or is a broken symlink;
+   other errors (such as permission errors) are propagated.
+
+
+.. method:: Path.is_symlink()
+
+   Return True if the path points to a symbolic link, False otherwise.
+
+   False is also returned if the path doesn't exist; other errors (such
+   as permission errors) are propagated.
+
+
+.. method:: Path.is_socket()
+
+   Return True if the path points to a Unix socket (or a symbolic link
+   pointing to a Unix socket), False if it points to another kind of file.
+
+   False is also returned if the path doesn't exist or is a broken symlink;
+   other errors (such as permission errors) are propagated.
+
+
+.. method:: Path.is_fifo()
+
+   Return True if the path points to a FIFO (or a symbolic link
+   pointing to a FIFO), False if it points to another kind of file.
+
+   False is also returned if the path doesn't exist or is a broken symlink;
+   other errors (such as permission errors) are propagated.
+
+
+.. method:: Path.is_block_device()
+
+   Return True if the path points to a block device (or a symbolic link
+   pointing to a block device), False if it points to another kind of file.
+
+   False is also returned if the path doesn't exist or is a broken symlink;
+   other errors (such as permission errors) are propagated.
+
+
+.. method:: Path.is_char_device()
+
+   Return True if the path points to a character device (or a symbolic link
+   pointing to a character device), False if it points to another kind of file.
+
+   False is also returned if the path doesn't exist or is a broken symlink;
+   other errors (such as permission errors) are propagated.
+
+
+.. method:: Path.iterdir()
+
+   When the path points to a directory, yield path objects of the directory
+   contents::
+
+      >>> p = Path('docs')
+      >>> for child in p.iterdir(): child
+      ...
+      PosixPath('docs/conf.py')
+      PosixPath('docs/_templates')
+      PosixPath('docs/make.bat')
+      PosixPath('docs/index.rst')
+      PosixPath('docs/_build')
+      PosixPath('docs/_static')
+      PosixPath('docs/Makefile')
+
+.. method:: Path.lchmod(mode)
+
+   Like :meth:`Path.chmod` but, if the path points to a symbolic link, the
+   symbolic link's mode is changed rather than its target's.
+
+
+.. method:: Path.lstat()
+
+   Like :meth:`Path.stat` but, if the path points to a symbolic link, return
+   the symbolic link's information rather than its target's.
+
+
+.. method:: Path.mkdir(mode=0o777, parents=False)
+
+   Create a new directory at this given path.  If *mode* is given, it is
+   combined with the process' ``umask`` value to determine the file mode
+   and access flags.  If the path already exists, :exc:`OSError` is raised.
+
+   If *parents* is True, any missing parents of this path are created
+   as needed.  If *parents* is False (the default), a missing parent raises
+   :exc:`OSError`.
+
+
+.. method:: Path.open(mode='r', buffering=-1, encoding=None, errors=None, newline=None)
+
+   Open the file pointed to by the path, like the built-in :func:`open`
+   function does::
+
+      >>> p = Path('setup.py')
+      >>> with p.open() as f:
+      ...     f.readline()
+      ...
+      '#!/usr/bin/env python3\n'
+
+
+.. method:: Path.owner()
+
+   Return the name of the user owning the file.  :exc:`KeyError` is thrown
+   if the file's uid isn't found in the system database.
+
+
+.. method:: Path.rename(target)
+
+   Rename this file or directory to the given *target*.  *target* can be
+   either a string or another path object::
+
+      >>> p = Path('foo')
+      >>> p.open('w').write('some text')
+      9
+      >>> target = Path('bar')
+      >>> p.rename(target)
+      >>> target.open().read()
+      'some text'
+
+
+.. method:: Path.replace(target)
+
+   Rename this file or directory to the given *target*.  If *target* points
+   to an existing file or directory, it will be unconditionally replaced.
+
+
+.. method:: Path.resolve()
+
+   Make the path absolute, resolving any symlinks.  A new path object is
+   returned::
+
+      >>> p = Path()
+      >>> p
+      PosixPath('.')
+      >>> p.resolve()
+      PosixPath('/home/antoine/pathlib')
+
+   `".."` components are also eliminated (this is the only method to do so)::
+
+      >>> p = Path('docs/../setup.py')
+      >>> p.resolve()
+      PosixPath('/home/antoine/pathlib/setup.py')
+
+   If the path doesn't exist, :exc:`FileNotFoundError` is raised.  If an
+   infinite loop is encountered along the resolution path,
+   :exc:`RuntimeError` is raised.
+
+
+.. method:: Path.rglob(pattern)
+
+   This is like calling :meth:`glob` with "``**``" added in front of the
+   given *pattern*:
+
+      >>> sorted(Path().rglob("*.py"))
+      [PosixPath('build/lib/pathlib.py'),
+       PosixPath('docs/conf.py'),
+       PosixPath('pathlib.py'),
+       PosixPath('setup.py'),
+       PosixPath('test_pathlib.py')]
+
+
+.. method:: Path.rmdir()
+
+   Remove this directory.  The directory must be empty.
+
+
+.. method:: Path.symlink_to(target, target_is_directory=False)
+
+   Make this path a symbolic link to *target*.  Under Windows,
+   *target_is_directory* must be True (default False) if the link's target
+   is a directory.  Under POSIX, *target_is_directory*'s value is ignored.
+
+      >>> p = Path('mylink')
+      >>> p.symlink_to('setup.py')
+      >>> p.resolve()
+      PosixPath('/home/antoine/pathlib/setup.py')
+      >>> p.stat().st_size
+      956
+      >>> p.lstat().st_size
+      8
+
+   .. note::
+      The order of arguments (link, target) is the reverse
+      of :func:`os.symlink`'s.
+
+
+.. method:: Path.touch(mode=0o777, exist_ok=True)
+
+   Create a file at this given path.  If *mode* is given, it is combined
+   with the process' ``umask`` value to determine the file mode and access
+   flags.  If the file already exists, the function succeeds if *exist_ok*
+   is true (and its modification time is updated to the current time),
+   otherwise :exc:`OSError` is raised.
+
+
+.. method:: Path.unlink()
+
+   Remove this file or symbolic link.  If the path points to a directory,
+   use :func:`Path.rmdir` instead.
+
diff --git a/Doc/whatsnew/3.4.rst b/Doc/whatsnew/3.4.rst
index 5ccbfa4..09d8be8 100644
--- a/Doc/whatsnew/3.4.rst
+++ b/Doc/whatsnew/3.4.rst
@@ -93,6 +93,7 @@ New library modules:
 * :mod:`asyncio`: New provisonal API for asynchronous IO (:pep:`3156`).
 * :mod:`enum`: Support for enumeration types (:pep:`435`).
 * :mod:`ensurepip`: Bootstrapping the pip installer (:pep:`453`).
+* :mod:`pathlib`: Object-oriented filesystem paths (:pep:`428`).
 * :mod:`selectors`: High-level and efficient I/O multiplexing, built upon the
   :mod:`select` module primitives.
 * :mod:`statistics`: A basic numerically stable statistics library (:pep:`450`).
@@ -318,6 +319,23 @@ compatible enumeration values.
       implemented by Ethan Furman.
 
 
+pathlib
+-------
+
+The new :mod:`pathlib` module offers classes representing filesystem paths
+with semantics appropriate for different operating systems.  Path classes are
+divided between *pure paths*, which provide purely computational operations
+without I/O, and *concrete paths*, which inherit from pure paths but also
+provide I/O operations.
+
+For Python 3.4, this module is considered a :term:`provisional API`.
+
+.. seealso::
+
+   :pep:`428` - The pathlib module -- object-oriented filesystem paths
+      PEP written and implemented by Antoine Pitrou.
+
+
 selectors
 ---------
 
diff --git a/Lib/pathlib.py b/Lib/pathlib.py
new file mode 100644
index 0000000..b81720e
--- /dev/null
+++ b/Lib/pathlib.py
@@ -0,0 +1,1287 @@
+import fnmatch
+import functools
+import io
+import ntpath
+import os
+import posixpath
+import re
+import sys
+import time
+import weakref
+try:
+    import threading
+except ImportError:
+    import dummy_threading as threading
+
+from collections import Sequence, defaultdict
+from contextlib import contextmanager
+from errno import EINVAL, ENOENT
+from itertools import chain, count
+from operator import attrgetter
+from stat import S_ISDIR, S_ISLNK, S_ISREG, S_ISSOCK, S_ISBLK, S_ISCHR, S_ISFIFO
+from urllib.parse import quote as urlquote, quote_from_bytes as urlquote_from_bytes
+
+
+supports_symlinks = True
+try:
+    import nt
+except ImportError:
+    nt = None
+else:
+    if sys.getwindowsversion()[:2] >= (6, 0):
+        from nt import _getfinalpathname
+    else:
+        supports_symlinks = False
+        _getfinalpathname = None
+
+
+__all__ = [
+    "PurePath", "PurePosixPath", "PureWindowsPath",
+    "Path", "PosixPath", "WindowsPath",
+    ]
+
+#
+# Internals
+#
+
+def _is_wildcard_pattern(pat):
+    # Whether this pattern needs actual matching using fnmatch, or can
+    # be looked up directly as a file.
+    return "*" in pat or "?" in pat or "[" in pat
+
+
+class _Flavour(object):
+    """A flavour implements a particular (platform-specific) set of path
+    semantics."""
+
+    def __init__(self):
+        self.join = self.sep.join
+
+    def parse_parts(self, parts):
+        parsed = []
+        sep = self.sep
+        altsep = self.altsep
+        drv = root = ''
+        it = reversed(parts)
+        for part in it:
+            if not part:
+                continue
+            if altsep:
+                part = part.replace(altsep, sep)
+            drv, root, rel = self.splitroot(part)
+            if sep in rel:
+                for x in reversed(rel.split(sep)):
+                    if x and x != '.':
+                        parsed.append(sys.intern(x))
+            else:
+                if rel and rel != '.':
+                    parsed.append(sys.intern(rel))
+            if drv or root:
+                if not drv:
+                    # If no drive is present, try to find one in the previous
+                    # parts. This makes the result of parsing e.g.
+                    # ("C:", "/", "a") reasonably intuitive.
+                    for part in it:
+                        drv = self.splitroot(part)[0]
+                        if drv:
+                            break
+                break
+        if drv or root:
+            parsed.append(drv + root)
+        parsed.reverse()
+        return drv, root, parsed
+
+    def join_parsed_parts(self, drv, root, parts, drv2, root2, parts2):
+        """
+        Join the two paths represented by the respective
+        (drive, root, parts) tuples.  Return a new (drive, root, parts) tuple.
+        """
+        if root2:
+            parts = parts2
+            root = root2
+        else:
+            parts = parts + parts2
+        # XXX raise error if drv and drv2 are different?
+        return drv2 or drv, root, parts
+
+
+class _WindowsFlavour(_Flavour):
+    # Reference for Windows paths can be found at
+    # http://msdn.microsoft.com/en-us/library/aa365247%28v=vs.85%29.aspx
+
+    sep = '\\'
+    altsep = '/'
+    has_drv = True
+    pathmod = ntpath
+
+    is_supported = (nt is not None)
+
+    drive_letters = (
+        set(chr(x) for x in range(ord('a'), ord('z') + 1)) |
+        set(chr(x) for x in range(ord('A'), ord('Z') + 1))
+    )
+    ext_namespace_prefix = '\\\\?\\'
+
+    reserved_names = (
+        {'CON', 'PRN', 'AUX', 'NUL'} |
+        {'COM%d' % i for i in range(1, 10)} |
+        {'LPT%d' % i for i in range(1, 10)}
+        )
+
+    # Interesting findings about extended paths:
+    # - '\\?\c:\a', '//?/c:\a' and '//?/c:/a' are all supported
+    #   but '\\?\c:/a' is not
+    # - extended paths are always absolute; "relative" extended paths will
+    #   fail.
+
+    def splitroot(self, part, sep=sep):
+        first = part[0:1]
+        second = part[1:2]
+        if (second == sep and first == sep):
+            # XXX extended paths should also disable the collapsing of "."
+            # components (according to MSDN docs).
+            prefix, part = self._split_extended_path(part)
+            first = part[0:1]
+            second = part[1:2]
+        else:
+            prefix = ''
+        third = part[2:3]
+        if (second == sep and first == sep and third != sep):
+            # is a UNC path:
+            # vvvvvvvvvvvvvvvvvvvvv root
+            # \\machine\mountpoint\directory\etc\...
+            #            directory ^^^^^^^^^^^^^^
+            index = part.find(sep, 2)
+            if index != -1:
+                index2 = part.find(sep, index + 1)
+                # a UNC path can't have two slashes in a row
+                # (after the initial two)
+                if index2 != index + 1:
+                    if index2 == -1:
+                        index2 = len(part)
+                    if prefix:
+                        return prefix + part[1:index2], sep, part[index2+1:]
+                    else:
+                        return part[:index2], sep, part[index2+1:]
+        drv = root = ''
+        if second == ':' and first in self.drive_letters:
+            drv = part[:2]
+            part = part[2:]
+            first = third
+        if first == sep:
+            root = first
+            part = part.lstrip(sep)
+        return prefix + drv, root, part
+
+    def casefold(self, s):
+        return s.lower()
+
+    def casefold_parts(self, parts):
+        return [p.lower() for p in parts]
+
+    def resolve(self, path):
+        s = str(path)
+        if not s:
+            return os.getcwd()
+        if _getfinalpathname is not None:
+            return self._ext_to_normal(_getfinalpathname(s))
+        # Means fallback on absolute
+        return None
+
+    def _split_extended_path(self, s, ext_prefix=ext_namespace_prefix):
+        prefix = ''
+        if s.startswith(ext_prefix):
+            prefix = s[:4]
+            s = s[4:]
+            if s.startswith('UNC\\'):
+                prefix += s[:3]
+                s = '\\' + s[3:]
+        return prefix, s
+
+    def _ext_to_normal(self, s):
+        # Turn back an extended path into a normal DOS-like path
+        return self._split_extended_path(s)[1]
+
+    def is_reserved(self, parts):
+        # NOTE: the rules for reserved names seem somewhat complicated
+        # (e.g. r"..\NUL" is reserved but not r"foo\NUL").
+        # We err on the side of caution and return True for paths which are
+        # not considered reserved by Windows.
+        if not parts:
+            return False
+        if parts[0].startswith('\\\\'):
+            # UNC paths are never reserved
+            return False
+        return parts[-1].partition('.')[0].upper() in self.reserved_names
+
+    def make_uri(self, path):
+        # Under Windows, file URIs use the UTF-8 encoding.
+        drive = path.drive
+        if len(drive) == 2 and drive[1] == ':':
+            # It's a path on a local drive => 'file:///c:/a/b'
+            rest = path.as_posix()[2:].lstrip('/')
+            return 'file:///%s/%s' % (
+                drive, urlquote_from_bytes(rest.encode('utf-8')))
+        else:
+            # It's a path on a network drive => 'file://host/share/a/b'
+            return 'file:' + urlquote_from_bytes(path.as_posix().encode('utf-8'))
+
+
+class _PosixFlavour(_Flavour):
+    sep = '/'
+    altsep = ''
+    has_drv = False
+    pathmod = posixpath
+
+    is_supported = (os.name != 'nt')
+
+    def splitroot(self, part, sep=sep):
+        if part and part[0] == sep:
+            stripped_part = part.lstrip(sep)
+            # According to POSIX path resolution:
+            # http://pubs.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap04.html#tag_04_11
+            # "A pathname that begins with two successive slashes may be
+            # interpreted in an implementation-defined manner, although more
+            # than two leading slashes shall be treated as a single slash".
+            if len(part) - len(stripped_part) == 2:
+                return '', sep * 2, stripped_part
+            else:
+                return '', sep, stripped_part
+        else:
+            return '', '', part
+
+    def casefold(self, s):
+        return s
+
+    def casefold_parts(self, parts):
+        return parts
+
+    def resolve(self, path):
+        sep = self.sep
+        def split(p):
+            return [x for x in p.split(sep) if x]
+        def absparts(p):
+            # Our own abspath(), since the posixpath one makes
+            # the mistake of "normalizing" the path without resolving the
+            # symlinks first.
+            if not p.startswith(sep):
+                return split(os.getcwd()) + split(p)
+            else:
+                return split(p)
+        parts = absparts(str(path))[::-1]
+        accessor = path._accessor
+        resolved = cur = ""
+        symlinks = {}
+        while parts:
+            part = parts.pop()
+            cur = resolved + sep + part
+            if cur in symlinks and symlinks[cur] <= len(parts):
+                # We've already seen the symlink and there's not less
+                # work to do than the last time.
+                raise RuntimeError("Symlink loop from %r" % cur)
+            try:
+                target = accessor.readlink(cur)
+            except OSError as e:
+                if e.errno != EINVAL:
+                    raise
+                # Not a symlink
+                resolved = cur
+            else:
+                # Take note of remaining work from this symlink
+                symlinks[cur] = len(parts)
+                if target.startswith(sep):
+                    # Symlink points to absolute path
+                    resolved = ""
+                parts.extend(split(target)[::-1])
+        return resolved or sep
+
+    def is_reserved(self, parts):
+        return False
+
+    def make_uri(self, path):
+        # We represent the path using the local filesystem encoding,
+        # for portability to other applications.
+        bpath = bytes(path)
+        return 'file://' + urlquote_from_bytes(bpath)
+
+
+_windows_flavour = _WindowsFlavour()
+_posix_flavour = _PosixFlavour()
+
+
+class _Accessor:
+    """An accessor implements a particular (system-specific or not) way of
+    accessing paths on the filesystem."""
+
+
+class _NormalAccessor(_Accessor):
+
+    def _wrap_strfunc(strfunc):
+        @functools.wraps(strfunc)
+        def wrapped(pathobj, *args):
+            return strfunc(str(pathobj), *args)
+        return staticmethod(wrapped)
+
+    def _wrap_binary_strfunc(strfunc):
+        @functools.wraps(strfunc)
+        def wrapped(pathobjA, pathobjB, *args):
+            return strfunc(str(pathobjA), str(pathobjB), *args)
+        return staticmethod(wrapped)
+
+    stat = _wrap_strfunc(os.stat)
+
+    lstat = _wrap_strfunc(os.lstat)
+
+    open = _wrap_strfunc(os.open)
+
+    listdir = _wrap_strfunc(os.listdir)
+
+    chmod = _wrap_strfunc(os.chmod)
+
+    if hasattr(os, "lchmod"):
+        lchmod = _wrap_strfunc(os.lchmod)
+    else:
+        def lchmod(self, pathobj, mode):
+            raise NotImplementedError("lchmod() not available on this system")
+
+    mkdir = _wrap_strfunc(os.mkdir)
+
+    unlink = _wrap_strfunc(os.unlink)
+
+    rmdir = _wrap_strfunc(os.rmdir)
+
+    rename = _wrap_binary_strfunc(os.rename)
+
+    replace = _wrap_binary_strfunc(os.replace)
+
+    if nt:
+        if supports_symlinks:
+            symlink = _wrap_binary_strfunc(os.symlink)
+        else:
+            def symlink(a, b, target_is_directory):
+                raise NotImplementedError("symlink() not available on this system")
+    else:
+        # Under POSIX, os.symlink() takes two args
+        @staticmethod
+        def symlink(a, b, target_is_directory):
+            return os.symlink(str(a), str(b))
+
+    utime = _wrap_strfunc(os.utime)
+
+    # Helper for resolve()
+    def readlink(self, path):
+        return os.readlink(path)
+
+
+_normal_accessor = _NormalAccessor()
+
+
+#
+# Globbing helpers
+#
+
+@contextmanager
+def _cached(func):
+    try:
+        func.__cached__
+        yield func
+    except AttributeError:
+        cache = {}
+        def wrapper(*args):
+            try:
+                return cache[args]
+            except KeyError:
+                value = cache[args] = func(*args)
+                return value
+        wrapper.__cached__ = True
+        try:
+            yield wrapper
+        finally:
+            cache.clear()
+
+def _make_selector(pattern_parts):
+    pat = pattern_parts[0]
+    child_parts = pattern_parts[1:]
+    if pat == '**':
+        cls = _RecursiveWildcardSelector
+    elif '**' in pat:
+        raise ValueError("Invalid pattern: '**' can only be an entire path component")
+    elif _is_wildcard_pattern(pat):
+        cls = _WildcardSelector
+    else:
+        cls = _PreciseSelector
+    return cls(pat, child_parts)
+
+if hasattr(functools, "lru_cache"):
+    _make_selector = functools.lru_cache()(_make_selector)
+
+
+class _Selector:
+    """A selector matches a specific glob pattern part against the children
+    of a given path."""
+
+    def __init__(self, child_parts):
+        self.child_parts = child_parts
+        if child_parts:
+            self.successor = _make_selector(child_parts)
+        else:
+            self.successor = _TerminatingSelector()
+
+    def select_from(self, parent_path):
+        """Iterate over all child paths of `parent_path` matched by this
+        selector.  This can contain parent_path itself."""
+        path_cls = type(parent_path)
+        is_dir = path_cls.is_dir
+        exists = path_cls.exists
+        listdir = parent_path._accessor.listdir
+        return self._select_from(parent_path, is_dir, exists, listdir)
+
+
+class _TerminatingSelector:
+
+    def _select_from(self, parent_path, is_dir, exists, listdir):
+        yield parent_path
+
+
+class _PreciseSelector(_Selector):
+
+    def __init__(self, name, child_parts):
+        self.name = name
+        _Selector.__init__(self, child_parts)
+
+    def _select_from(self, parent_path, is_dir, exists, listdir):
+        if not is_dir(parent_path):
+            return
+        path = parent_path._make_child_relpath(self.name)
+        if exists(path):
+            for p in self.successor._select_from(path, is_dir, exists, listdir):
+                yield p
+
+
+class _WildcardSelector(_Selector):
+
+    def __init__(self, pat, child_parts):
+        self.pat = re.compile(fnmatch.translate(pat))
+        _Selector.__init__(self, child_parts)
+
+    def _select_from(self, parent_path, is_dir, exists, listdir):
+        if not is_dir(parent_path):
+            return
+        cf = parent_path._flavour.casefold
+        for name in listdir(parent_path):
+            casefolded = cf(name)
+            if self.pat.match(casefolded):
+                path = parent_path._make_child_relpath(name)
+                for p in self.successor._select_from(path, is_dir, exists, listdir):
+                    yield p
+
+
+class _RecursiveWildcardSelector(_Selector):
+
+    def __init__(self, pat, child_parts):
+        _Selector.__init__(self, child_parts)
+
+    def _iterate_directories(self, parent_path, is_dir, listdir):
+        yield parent_path
+        for name in listdir(parent_path):
+            path = parent_path._make_child_relpath(name)
+            if is_dir(path):
+                for p in self._iterate_directories(path, is_dir, listdir):
+                    yield p
+
+    def _select_from(self, parent_path, is_dir, exists, listdir):
+        if not is_dir(parent_path):
+            return
+        with _cached(listdir) as listdir:
+            yielded = set()
+            try:
+                successor_select = self.successor._select_from
+                for starting_point in self._iterate_directories(parent_path, is_dir, listdir):
+                    for p in successor_select(starting_point, is_dir, exists, listdir):
+                        if p not in yielded:
+                            yield p
+                            yielded.add(p)
+            finally:
+                yielded.clear()
+
+
+#
+# Public API
+#
+
+class _PathParents(Sequence):
+    """This object provides sequence-like access to the logical ancestors
+    of a path.  Don't try to construct it yourself."""
+    __slots__ = ('_pathcls', '_drv', '_root', '_parts')
+
+    def __init__(self, path):
+        # We don't store the instance to avoid reference cycles
+        self._pathcls = type(path)
+        self._drv = path._drv
+        self._root = path._root
+        self._parts = path._parts
+
+    def __len__(self):
+        if self._drv or self._root:
+            return len(self._parts) - 1
+        else:
+            return len(self._parts)
+
+    def __getitem__(self, idx):
+        if idx < 0 or idx >= len(self):
+            raise IndexError(idx)
+        return self._pathcls._from_parsed_parts(self._drv, self._root,
+                                                self._parts[:-idx - 1])
+
+    def __repr__(self):
+        return "<{}.parents>".format(self._pathcls.__name__)
+
+
+class PurePath(object):
+    """PurePath represents a filesystem path and offers operations which
+    don't imply any actual filesystem I/O.  Depending on your system,
+    instantiating a PurePath will return either a PurePosixPath or a
+    PureWindowsPath object.  You can also instantiate either of these classes
+    directly, regardless of your system.
+    """
+    __slots__ = (
+        '_drv', '_root', '_parts',
+        '_str', '_hash', '_pparts', '_cached_cparts',
+    )
+
+    def __new__(cls, *args):
+        """Construct a PurePath from one or several strings and or existing
+        PurePath objects.  The strings and path objects are combined so as
+        to yield a canonicalized path, which is incorporated into the
+        new PurePath object.
+        """
+        if cls is PurePath:
+            cls = PureWindowsPath if os.name == 'nt' else PurePosixPath
+        return cls._from_parts(args)
+
+    def __reduce__(self):
+        # Using the parts tuple helps share interned path parts
+        # when pickling related paths.
+        return (self.__class__, tuple(self._parts))
+
+    @classmethod
+    def _parse_args(cls, args):
+        # This is useful when you don't want to create an instance, just
+        # canonicalize some constructor arguments.
+        parts = []
+        for a in args:
+            if isinstance(a, PurePath):
+                parts += a._parts
+            elif isinstance(a, str):
+                # Assuming a str
+                parts.append(a)
+            else:
+                raise TypeError(
+                    "argument should be a path or str object, not %r"
+                    % type(a))
+        return cls._flavour.parse_parts(parts)
+
+    @classmethod
+    def _from_parts(cls, args, init=True):
+        # We need to call _parse_args on the instance, so as to get the
+        # right flavour.
+        self = object.__new__(cls)
+        drv, root, parts = self._parse_args(args)
+        self._drv = drv
+        self._root = root
+        self._parts = parts
+        if init:
+            self._init()
+        return self
+
+    @classmethod
+    def _from_parsed_parts(cls, drv, root, parts, init=True):
+        self = object.__new__(cls)
+        self._drv = drv
+        self._root = root
+        self._parts = parts
+        if init:
+            self._init()
+        return self
+
+    @classmethod
+    def _format_parsed_parts(cls, drv, root, parts):
+        if drv or root:
+            return drv + root + cls._flavour.join(parts[1:])
+        else:
+            return cls._flavour.join(parts)
+
+    def _init(self):
+        # Overriden in concrete Path
+        pass
+
+    def _make_child(self, args):
+        drv, root, parts = self._parse_args(args)
+        drv, root, parts = self._flavour.join_parsed_parts(
+            self._drv, self._root, self._parts, drv, root, parts)
+        return self._from_parsed_parts(drv, root, parts)
+
+    def __str__(self):
+        """Return the string representation of the path, suitable for
+        passing to system calls."""
+        try:
+            return self._str
+        except AttributeError:
+            self._str = self._format_parsed_parts(self._drv, self._root,
+                                                  self._parts) or '.'
+            return self._str
+
+    def as_posix(self):
+        """Return the string representation of the path with forward (/)
+        slashes."""
+        f = self._flavour
+        return str(self).replace(f.sep, '/')
+
+    def __bytes__(self):
+        """Return the bytes representation of the path.  This is only
+        recommended to use under Unix."""
+        return os.fsencode(str(self))
+
+    def __repr__(self):
+        return "{}({!r})".format(self.__class__.__name__, self.as_posix())
+
+    def as_uri(self):
+        """Return the path as a 'file' URI."""
+        if not self.is_absolute():
+            raise ValueError("relative path can't be expressed as a file URI")
+        return self._flavour.make_uri(self)
+
+    @property
+    def _cparts(self):
+        # Cached casefolded parts, for hashing and comparison
+        try:
+            return self._cached_cparts
+        except AttributeError:
+            self._cached_cparts = self._flavour.casefold_parts(self._parts)
+            return self._cached_cparts
+
+    def __eq__(self, other):
+        if not isinstance(other, PurePath):
+            return NotImplemented
+        return self._cparts == other._cparts and self._flavour is other._flavour
+
+    def __ne__(self, other):
+        return not self == other
+
+    def __hash__(self):
+        try:
+            return self._hash
+        except AttributeError:
+            self._hash = hash(tuple(self._cparts))
+            return self._hash
+
+    def __lt__(self, other):
+        if not isinstance(other, PurePath) or self._flavour is not other._flavour:
+            return NotImplemented
+        return self._cparts < other._cparts
+
+    def __le__(self, other):
+        if not isinstance(other, PurePath) or self._flavour is not other._flavour:
+            return NotImplemented
+        return self._cparts <= other._cparts
+
+    def __gt__(self, other):
+        if not isinstance(other, PurePath) or self._flavour is not other._flavour:
+            return NotImplemented
+        return self._cparts > other._cparts
+
+    def __ge__(self, other):
+        if not isinstance(other, PurePath) or self._flavour is not other._flavour:
+            return NotImplemented
+        return self._cparts >= other._cparts
+
+    drive = property(attrgetter('_drv'),
+                     doc="""The drive prefix (letter or UNC path), if any.""")
+
+    root = property(attrgetter('_root'),
+                    doc="""The root of the path, if any.""")
+
+    @property
+    def anchor(self):
+        """The concatenation of the drive and root, or ''."""
+        anchor = self._drv + self._root
+        return anchor
+
+    @property
+    def name(self):
+        """The final path component, if any."""
+        parts = self._parts
+        if len(parts) == (1 if (self._drv or self._root) else 0):
+            return ''
+        return parts[-1]
+
+    @property
+    def suffix(self):
+        """The final component's last suffix, if any."""
+        name = self.name
+        i = name.rfind('.')
+        if 0 < i < len(name) - 1:
+            return name[i:]
+        else:
+            return ''
+
+    @property
+    def suffixes(self):
+        """A list of the final component's suffixes, if any."""
+        name = self.name
+        if name.endswith('.'):
+            return []
+        name = name.lstrip('.')
+        return ['.' + suffix for suffix in name.split('.')[1:]]
+
+    @property
+    def stem(self):
+        """The final path component, minus its last suffix."""
+        name = self.name
+        i = name.rfind('.')
+        if 0 < i < len(name) - 1:
+            return name[:i]
+        else:
+            return name
+
+    def with_name(self, name):
+        """Return a new path with the file name changed."""
+        if not self.name:
+            raise ValueError("%r has an empty name" % (self,))
+        return self._from_parsed_parts(self._drv, self._root,
+                                       self._parts[:-1] + [name])
+
+    def with_suffix(self, suffix):
+        """Return a new path with the file suffix changed (or added, if none)."""
+        # XXX if suffix is None, should the current suffix be removed?
+        name = self.name
+        if not name:
+            raise ValueError("%r has an empty name" % (self,))
+        old_suffix = self.suffix
+        if not old_suffix:
+            name = name + suffix
+        else:
+            name = name[:-len(old_suffix)] + suffix
+        return self._from_parsed_parts(self._drv, self._root,
+                                       self._parts[:-1] + [name])
+
+    def relative_to(self, *other):
+        """Return the relative path to another path identified by the passed
+        arguments.  If the operation is not possible (because this is not
+        a subpath of the other path), raise ValueError.
+        """
+        # For the purpose of this method, drive and root are considered
+        # separate parts, i.e.:
+        #   Path('c:/').relative_to('c:')  gives Path('/')
+        #   Path('c:/').relative_to('/')   raise ValueError
+        if not other:
+            raise TypeError("need at least one argument")
+        parts = self._parts
+        drv = self._drv
+        root = self._root
+        if drv or root:
+            if root:
+                abs_parts = [drv, root] + parts[1:]
+            else:
+                abs_parts = [drv] + parts[1:]
+        else:
+            abs_parts = parts
+        to_drv, to_root, to_parts = self._parse_args(other)
+        if to_drv or to_root:
+            if to_root:
+                to_abs_parts = [to_drv, to_root] + to_parts[1:]
+            else:
+                to_abs_parts = [to_drv] + to_parts[1:]
+        else:
+            to_abs_parts = to_parts
+        n = len(to_abs_parts)
+        if n == 0 and (drv or root) or abs_parts[:n] != to_abs_parts:
+            formatted = self._format_parsed_parts(to_drv, to_root, to_parts)
+            raise ValueError("{!r} does not start with {!r}"
+                             .format(str(self), str(formatted)))
+        return self._from_parsed_parts('', '', abs_parts[n:])
+
+    @property
+    def parts(self):
+        """An object providing sequence-like access to the
+        components in the filesystem path."""
+        # We cache the tuple to avoid building a new one each time .parts
+        # is accessed.  XXX is this necessary?
+        try:
+            return self._pparts
+        except AttributeError:
+            self._pparts = tuple(self._parts)
+            return self._pparts
+
+    def joinpath(self, *args):
+        """Combine this path with one or several arguments, and return a
+        new path representing either a subpath (if all arguments are relative
+        paths) or a totally different path (if one of the arguments is
+        anchored).
+        """
+        return self._make_child(args)
+
+    def __truediv__(self, key):
+        return self._make_child((key,))
+
+    def __rtruediv__(self, key):
+        return self._from_parts([key] + self._parts)
+
+    @property
+    def parent(self):
+        """The logical parent of the path."""
+        drv = self._drv
+        root = self._root
+        parts = self._parts
+        if len(parts) == 1 and (drv or root):
+            return self
+        return self._from_parsed_parts(drv, root, parts[:-1])
+
+    @property
+    def parents(self):
+        """A sequence of this path's logical parents."""
+        return _PathParents(self)
+
+    def is_absolute(self):
+        """True if the path is absolute (has both a root and, if applicable,
+        a drive)."""
+        if not self._root:
+            return False
+        return not self._flavour.has_drv or bool(self._drv)
+
+    def is_reserved(self):
+        """Return True if the path contains one of the special names reserved
+        by the system, if any."""
+        return self._flavour.is_reserved(self._parts)
+
+    def match(self, path_pattern):
+        """
+        Return True if this path matches the given pattern.
+        """
+        cf = self._flavour.casefold
+        path_pattern = cf(path_pattern)
+        drv, root, pat_parts = self._flavour.parse_parts((path_pattern,))
+        if not pat_parts:
+            raise ValueError("empty pattern")
+        if drv and drv != cf(self._drv):
+            return False
+        if root and root != cf(self._root):
+            return False
+        parts = self._cparts
+        if drv or root:
+            if len(pat_parts) != len(parts):
+                return False
+            pat_parts = pat_parts[1:]
+        elif len(pat_parts) > len(parts):
+            return False
+        for part, pat in zip(reversed(parts), reversed(pat_parts)):
+            if not fnmatch.fnmatchcase(part, pat):
+                return False
+        return True
+
+
+class PurePosixPath(PurePath):
+    _flavour = _posix_flavour
+    __slots__ = ()
+
+
+class PureWindowsPath(PurePath):
+    _flavour = _windows_flavour
+    __slots__ = ()
+
+
+# Filesystem-accessing classes
+
+
+class Path(PurePath):
+    __slots__ = (
+        '_accessor',
+        '_closed',
+    )
+
+    def __new__(cls, *args, **kwargs):
+        if cls is Path:
+            cls = WindowsPath if os.name == 'nt' else PosixPath
+        self = cls._from_parts(args, init=False)
+        if not self._flavour.is_supported:
+            raise NotImplementedError("cannot instantiate %r on your system"
+                                      % (cls.__name__,))
+        self._init()
+        return self
+
+    def _init(self,
+              # Private non-constructor arguments
+              template=None,
+              ):
+        self._closed = False
+        if template is not None:
+            self._accessor = template._accessor
+        else:
+            self._accessor = _normal_accessor
+
+    def _make_child_relpath(self, part):
+        # This is an optimization used for dir walking.  `part` must be
+        # a single part relative to this path.
+        parts = self._parts + [part]
+        return self._from_parsed_parts(self._drv, self._root, parts)
+
+    def __enter__(self):
+        if self._closed:
+            self._raise_closed()
+        return self
+
+    def __exit__(self, t, v, tb):
+        self._closed = True
+
+    def _raise_closed(self):
+        raise ValueError("I/O operation on closed path")
+
+    def _opener(self, name, flags, mode=0o666):
+        # A stub for the opener argument to built-in open()
+        return self._accessor.open(self, flags, mode)
+
+    # Public API
+
+    @classmethod
+    def cwd(cls):
+        """Return a new path pointing to the current working directory
+        (as returned by os.getcwd()).
+        """
+        return cls(os.getcwd())
+
+    def iterdir(self):
+        """Iterate over the files in this directory.  Does not yield any
+        result for the special paths '.' and '..'.
+        """
+        if self._closed:
+            self._raise_closed()
+        for name in self._accessor.listdir(self):
+            if name in {'.', '..'}:
+                # Yielding a path object for these makes little sense
+                continue
+            yield self._make_child_relpath(name)
+            if self._closed:
+                self._raise_closed()
+
+    def glob(self, pattern):
+        """Iterate over this subtree and yield all existing files (of any
+        kind, including directories) matching the given pattern.
+        """
+        pattern = self._flavour.casefold(pattern)
+        drv, root, pattern_parts = self._flavour.parse_parts((pattern,))
+        if drv or root:
+            raise NotImplementedError("Non-relative patterns are unsupported")
+        selector = _make_selector(tuple(pattern_parts))
+        for p in selector.select_from(self):
+            yield p
+
+    def rglob(self, pattern):
+        """Recursively yield all existing files (of any kind, including
+        directories) matching the given pattern, anywhere in this subtree.
+        """
+        pattern = self._flavour.casefold(pattern)
+        drv, root, pattern_parts = self._flavour.parse_parts((pattern,))
+        if drv or root:
+            raise NotImplementedError("Non-relative patterns are unsupported")
+        selector = _make_selector(("**",) + tuple(pattern_parts))
+        for p in selector.select_from(self):
+            yield p
+
+    def absolute(self):
+        """Return an absolute version of this path.  This function works
+        even if the path doesn't point to anything.
+
+        No normalization is done, i.e. all '.' and '..' will be kept along.
+        Use resolve() to get the canonical path to a file.
+        """
+        # XXX untested yet!
+        if self._closed:
+            self._raise_closed()
+        if self.is_absolute():
+            return self
+        # FIXME this must defer to the specific flavour (and, under Windows,
+        # use nt._getfullpathname())
+        obj = self._from_parts([os.getcwd()] + self._parts, init=False)
+        obj._init(template=self)
+        return obj
+
+    def resolve(self):
+        """
+        Make the path absolute, resolving all symlinks on the way and also
+        normalizing it (for example turning slashes into backslashes under
+        Windows).
+        """
+        if self._closed:
+            self._raise_closed()
+        s = self._flavour.resolve(self)
+        if s is None:
+            # No symlink resolution => for consistency, raise an error if
+            # the path doesn't exist or is forbidden
+            self.stat()
+            s = str(self.absolute())
+        # Now we have no symlinks in the path, it's safe to normalize it.
+        normed = self._flavour.pathmod.normpath(s)
+        obj = self._from_parts((normed,), init=False)
+        obj._init(template=self)
+        return obj
+
+    def stat(self):
+        """
+        Return the result of the stat() system call on this path, like
+        os.stat() does.
+        """
+        return self._accessor.stat(self)
+
+    def owner(self):
+        """
+        Return the login name of the file owner.
+        """
+        import pwd
+        return pwd.getpwuid(self.stat().st_uid).pw_name
+
+    def group(self):
+        """
+        Return the group name of the file gid.
+        """
+        import grp
+        return grp.getgrgid(self.stat().st_gid).gr_name
+
+    def _raw_open(self, flags, mode=0o777):
+        """
+        Open the file pointed by this path and return a file descriptor,
+        as os.open() does.
+        """
+        if self._closed:
+            self._raise_closed()
+        return self._accessor.open(self, flags, mode)
+
+    def open(self, mode='r', buffering=-1, encoding=None,
+             errors=None, newline=None):
+        """
+        Open the file pointed by this path and return a file object, as
+        the built-in open() function does.
+        """
+        if self._closed:
+            self._raise_closed()
+        return io.open(str(self), mode, buffering, encoding, errors, newline,
+                       opener=self._opener)
+
+    def touch(self, mode=0o666, exist_ok=True):
+        """
+        Create this file with the given access mode, if it doesn't exist.
+        """
+        if self._closed:
+            self._raise_closed()
+        if exist_ok:
+            # First try to bump modification time
+            # Implementation note: GNU touch uses the UTIME_NOW option of
+            # the utimensat() / futimens() functions.
+            t = time.time()
+            try:
+                self._accessor.utime(self, (t, t))
+            except OSError:
+                # Avoid exception chaining
+                pass
+            else:
+                return
+        flags = os.O_CREAT | os.O_WRONLY
+        if not exist_ok:
+            flags |= os.O_EXCL
+        fd = self._raw_open(flags, mode)
+        os.close(fd)
+
+    def mkdir(self, mode=0o777, parents=False):
+        if self._closed:
+            self._raise_closed()
+        if not parents:
+            self._accessor.mkdir(self, mode)
+        else:
+            try:
+                self._accessor.mkdir(self, mode)
+            except OSError as e:
+                if e.errno != ENOENT:
+                    raise
+                self.parent.mkdir(mode, True)
+                self._accessor.mkdir(self, mode)
+
+    def chmod(self, mode):
+        """
+        Change the permissions of the path, like os.chmod().
+        """
+        if self._closed:
+            self._raise_closed()
+        self._accessor.chmod(self, mode)
+
+    def lchmod(self, mode):
+        """
+        Like chmod(), except if the path points to a symlink, the symlink's
+        permissions are changed, rather than its target's.
+        """
+        if self._closed:
+            self._raise_closed()
+        self._accessor.lchmod(self, mode)
+
+    def unlink(self):
+        """
+        Remove this file or link.
+        If the path is a directory, use rmdir() instead.
+        """
+        if self._closed:
+            self._raise_closed()
+        self._accessor.unlink(self)
+
+    def rmdir(self):
+        """
+        Remove this directory.  The directory must be empty.
+        """
+        if self._closed:
+            self._raise_closed()
+        self._accessor.rmdir(self)
+
+    def lstat(self):
+        """
+        Like stat(), except if the path points to a symlink, the symlink's
+        status information is returned, rather than its target's.
+        """
+        if self._closed:
+            self._raise_closed()
+        return self._accessor.lstat(self)
+
+    def rename(self, target):
+        """
+        Rename this path to the given path.
+        """
+        if self._closed:
+            self._raise_closed()
+        self._accessor.rename(self, target)
+
+    def replace(self, target):
+        """
+        Rename this path to the given path, clobbering the existing
+        destination if it exists.
+        """
+        if self._closed:
+            self._raise_closed()
+        self._accessor.replace(self, target)
+
+    def symlink_to(self, target, target_is_directory=False):
+        """
+        Make this path a symlink pointing to the given path.
+        Note the order of arguments (self, target) is the reverse of os.symlink's.
+        """
+        if self._closed:
+            self._raise_closed()
+        self._accessor.symlink(target, self, target_is_directory)
+
+    # Convenience functions for querying the stat results
+
+    def exists(self):
+        """
+        Whether this path exists.
+        """
+        try:
+            self.stat()
+        except OSError as e:
+            if e.errno != ENOENT:
+                raise
+            return False
+        return True
+
+    def is_dir(self):
+        """
+        Whether this path is a directory.
+        """
+        try:
+            return S_ISDIR(self.stat().st_mode)
+        except OSError as e:
+            if e.errno != ENOENT:
+                raise
+            # Path doesn't exist or is a broken symlink
+            # (see https://bitbucket.org/pitrou/pathlib/issue/12/)
+            return False
+
+    def is_file(self):
+        """
+        Whether this path is a regular file (also True for symlinks pointing
+        to regular files).
+        """
+        try:
+            return S_ISREG(self.stat().st_mode)
+        except OSError as e:
+            if e.errno != ENOENT:
+                raise
+            # Path doesn't exist or is a broken symlink
+            # (see https://bitbucket.org/pitrou/pathlib/issue/12/)
+            return False
+
+    def is_symlink(self):
+        """
+        Whether this path is a symbolic link.
+        """
+        try:
+            return S_ISLNK(self.lstat().st_mode)
+        except OSError as e:
+            if e.errno != ENOENT:
+                raise
+            # Path doesn't exist
+            return False
+
+    def is_block_device(self):
+        """
+        Whether this path is a block device.
+        """
+        try:
+            return S_ISBLK(self.stat().st_mode)
+        except OSError as e:
+            if e.errno != ENOENT:
+                raise
+            # Path doesn't exist or is a broken symlink
+            # (see https://bitbucket.org/pitrou/pathlib/issue/12/)
+            return False
+
+    def is_char_device(self):
+        """
+        Whether this path is a character device.
+        """
+        try:
+            return S_ISCHR(self.stat().st_mode)
+        except OSError as e:
+            if e.errno != ENOENT:
+                raise
+            # Path doesn't exist or is a broken symlink
+            # (see https://bitbucket.org/pitrou/pathlib/issue/12/)
+            return False
+
+    def is_fifo(self):
+        """
+        Whether this path is a FIFO.
+        """
+        try:
+            return S_ISFIFO(self.stat().st_mode)
+        except OSError as e:
+            if e.errno != ENOENT:
+                raise
+            # Path doesn't exist or is a broken symlink
+            # (see https://bitbucket.org/pitrou/pathlib/issue/12/)
+            return False
+
+    def is_socket(self):
+        """
+        Whether this path is a socket.
+        """
+        try:
+            return S_ISSOCK(self.stat().st_mode)
+        except OSError as e:
+            if e.errno != ENOENT:
+                raise
+            # Path doesn't exist or is a broken symlink
+            # (see https://bitbucket.org/pitrou/pathlib/issue/12/)
+            return False
+
+
+class PosixPath(Path, PurePosixPath):
+    __slots__ = ()
+
+class WindowsPath(Path, PureWindowsPath):
+    __slots__ = ()
+
diff --git a/Lib/test/test_pathlib.py b/Lib/test/test_pathlib.py
new file mode 100755
index 0000000..8c0c430
--- /dev/null
+++ b/Lib/test/test_pathlib.py
@@ -0,0 +1,1639 @@
+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):
+        from urllib.parse import quote_from_bytes
+        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')
+        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()
diff --git a/Misc/NEWS b/Misc/NEWS
index 35bca00..fdbff70 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -65,6 +65,8 @@ Core and Builtins
 Library
 -------
 
+- Issue #19673: Add pathlib to the stdlib as a provisional module (PEP 428).
+
 - Issue #17916: Added dis.Bytecode.from_traceback() and
   dis.Bytecode.current_offset to easily display "current instruction"
   markers in the new disassembly API (Patch by Claudiu Popa).