Don't make assumptions about fs case sensitivity in make_numbered_dir

CHANGELOG

@@ -1,6 +1,8 @@
 (unreleased)
 ============
 
+- fix pytest-dev/pytest#3451: don't make assumptions about fs case sensitivity
+  in ``make_numbered_dir``.
 
 1.5.3
 =====

py/_path/local.py

@@ -4,13 +4,13 @@
 from __future__ import with_statement
 
 from contextlib import contextmanager
-import sys, os, re, atexit, io, uuid
+import sys, os, atexit, io, uuid
 import py
 from py._path import common
 from py._path.common import iswin32, fspath
 from stat import S_ISLNK, S_ISDIR, S_ISREG
 
-from os.path import abspath, normcase, normpath, isabs, exists, isdir, isfile, islink, dirname
+from os.path import abspath, normpath, isabs, exists, isdir, isfile, islink, dirname
 
 if sys.version_info > (3,0):
     def map_as_list(func, iter):
@@ -800,7 +800,7 @@ def mkdtemp(cls, rootdir=None):
         return cls(py.error.checked_call(tempfile.mkdtemp, dir=str(rootdir)))
 
     def make_numbered_dir(cls, prefix='session-', rootdir=None, keep=3,
-                          lock_timeout = 172800):   # two days
+                          lock_timeout=172800):   # two days
         """ return unique directory with a number greater than the current
             maximum one.  The number is assumed to start directly after prefix.
             if keep is true directories with a number less than (maxnum-keep)
@@ -810,10 +810,10 @@ def make_numbered_dir(cls, prefix='session-', rootdir=None, keep=3,
         if rootdir is None:
             rootdir = cls.get_temproot()
 
-        nprefix = normcase(prefix)
+        nprefix = prefix.lower()
         def parse_num(path):
             """ parse the number out of a path (if it matches the prefix) """
-            nbasename = normcase(path.basename)
+            nbasename = path.basename.lower()
             if nbasename.startswith(nprefix):
                 try:
                     return int(nbasename[len(nprefix):])

testing/path/test_local.py

@@ -425,24 +425,23 @@ def test_make_numbered_dir(self, tmpdir):
             if i >= 3:
                 assert not numdir.new(ext=str(i-3)).check()
 
-    def test_make_numbered_dir_case_insensitive(self, tmpdir, monkeypatch):
-        # https://github.com/pytest-dev/pytest/issues/708
-        monkeypatch.setattr(py._path.local, 'normcase',
-                            lambda path: path.lower())
-        monkeypatch.setattr(tmpdir, 'listdir',
-                            lambda: [tmpdir._fastjoin('case.0')])
-        numdir = local.make_numbered_dir(prefix='CAse.', rootdir=tmpdir,
-                                         keep=2, lock_timeout=0)
-        assert numdir.basename.endswith('.1')
-
-    def test_make_numbered_dir_case_sensitive(self, tmpdir, monkeypatch):
-        # https://github.com/pytest-dev/pytest/issues/708
-        monkeypatch.setattr(py._path.local, 'normcase', lambda path: path)
-        monkeypatch.setattr(tmpdir, 'listdir',
-                            lambda: [tmpdir._fastjoin('case.0')])
-        numdir = local.make_numbered_dir(prefix='CAse.', rootdir=tmpdir,
-                                         keep=2, lock_timeout=0)
-        assert numdir.basename.endswith('.0')
+    def test_make_numbered_dir_case(self, tmpdir):
+        """make_numbered_dir does not make assumptions on the underlying
+        filesystem based on the platform and will assume it _could_ be case
+        insensitive.
+
+        See issues:
+        - https://github.com/pytest-dev/pytest/issues/708
+        - https://github.com/pytest-dev/pytest/issues/3451
+        """
+        d1 = local.make_numbered_dir(
+            prefix='CAse.', rootdir=tmpdir, keep=2, lock_timeout=0,
+        )
+        d2 = local.make_numbered_dir(
+            prefix='caSE.', rootdir=tmpdir, keep=2, lock_timeout=0,
+        )
+        assert str(d1).lower() != str(d2).lower()
+        assert str(d2).endswith('.1')
 
     def test_make_numbered_dir_NotImplemented_Error(self, tmpdir, monkeypatch):
         def notimpl(x, y):