change case insensitivity test (#282)

* change case insensitivity test

* changelog

Author: willmcgugan

CHANGELOG.md

@@ -5,7 +5,7 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
-## [Unreleased]
+## [2.4.5] - 2019-05-05
 
 ### Fixed
 
@@ -15,7 +15,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ### Changed
 
-- Removed case_insensitive meta value from OSFS meta on OSX. normcase check doesn't work on OSX (https://stackoverflow.com/questions/7870041/check-if-file-system-is-case-insensitive-in-python)
+- Detect case insensitivity using by writing temp file
 
 ## [2.4.4] - 2019-02-23
 

fs/osfs.py

@@ -17,6 +17,7 @@
 import shutil
 import stat
 import sys
+import tempfile
 import typing
 
 import six
@@ -134,7 +135,6 @@ def __init__(
                 raise errors.CreateFailed("root path does not exist")
 
         _meta = self._meta = {
-            "case_insensitive": os.path.normcase("Aa") == "aa",
             "network": False,
             "read_only": False,
             "supports_rename": True,
@@ -143,10 +143,14 @@ def __init__(
             "virtual": False,
         }
 
-        if platform.system() == "Darwin":
-            # Standard test doesn't work on OSX.
-            # Best we can say is we don't know.
-            del _meta["case_insensitive"]
+        try:
+            # https://stackoverflow.com/questions/7870041/check-if-file-system-is-case-insensitive-in-python
+            # I don't know of a better way of detecting case insensitivity of a filesystem
+            with tempfile.NamedTemporaryFile(prefix="TmP") as _tmp_file:
+                _meta["case_insensitive"] = os.path.exists(_tmp_file.name.lower())
+        except Exception:
+            if platform.system() != "Darwin":
+                _meta["case_insensitive"] = os.path.normcase("Aa") == "aa"
 
         if _WINDOWS_PLATFORM:  # pragma: no cover
             _meta["invalid_path_chars"] = (