Fix path splitter issue on Windows

If a unix-style absolute path is given to the path_splitter on Windows,
the first element was a unix-style path separator and not a Windows path
sparator. This has been fixed.

The docstring has updated to be true for all OSes.

Unit tests are updated to account for this change.

2 files changed, 10 insertions, 5 deletions

diff --git a/natsort/utils.py b/natsort/utils.py
index 4db0f80..61387d3 100644
--- a/natsort/utils.py
+++ b/natsort/utils.py
@@ -47,6 +47,7 @@ from itertools import chain as ichain
 from operator import methodcaller
 from os import curdir as os_curdir
 from os import pardir as os_pardir
+from os import sep as os_sep
 from os.path import split as path_split
 from os.path import splitext as path_splitext
 from unicodedata import normalize
@@ -743,8 +744,8 @@ def path_splitter(s, _d_match=re.compile(r"\.\d").match):
     Examples
     --------
 
-        >>> tuple(path_splitter("/this/thing.ext"))
-        ({u}'/', {u}'this', {u}'thing', {u}'.ext')
+        >>> tuple(path_splitter("this/thing.ext"))
+        ({u}'this', {u}'thing', {u}'.ext')
 
     """
     if has_pathlib and isinstance(s, PurePath):
@@ -763,8 +764,10 @@ def path_splitter(s, _d_match=re.compile(r"\.\d").match):
 
     # This last append is the base path.
     # Only append if the string is non-empty.
+    # Make sure the proper path separator for this OS is used
+    # no matter what was actually given.
     if path_location:
-        p_appendleft(path_location)
+        p_appendleft(py23_str(os_sep))
 
     # Now, split off the file extensions using a similar method to above.
     # Continue splitting off file extensions until we reach a decimal number
diff --git a/tests/test_natsort_keygen.py b/tests/test_natsort_keygen.py
index baa4c3e..0cf5fa6 100644
--- a/tests/test_natsort_keygen.py
+++ b/tests/test_natsort_keygen.py
@@ -5,10 +5,12 @@ See the README or the natsort homepage for more details.
 """
 from __future__ import print_function, unicode_literals
 
+import os
+
 import pytest
 from natsort import natsort_key, natsort_keygen, natsorted, ns
 from natsort.compat.locale import get_strxfrm, null_string_locale
-from natsort.compat.py23 import PY_VERSION
+from natsort.compat.py23 import PY_VERSION, py23_str
 
 
 @pytest.fixture
@@ -72,7 +74,7 @@ def test_natsort_keygen_returns_natsort_key_that_parses_input(alg, expected):
             ns.PATH | ns.GROUPLETTERS,
             (
                 (("", 6, "aA--", 5, "..", 34, "ee++", 1),),
-                (("//",), ("fFoollddeerr  ((", 1, "))"), ("fFoooo",)),
+                ((2 * py23_str(os.sep),), ("fFoollddeerr  ((", 1, "))"), ("fFoooo",)),
                 (("", 56.7),),
             ),
         ),