better directory-ness checking for file: scheme index URLs

pip/index.py

@@ -386,8 +386,8 @@ class HTMLPage(object):
             logger.debug('Getting page %s' % url)
             
             # Tack index.html onto file:// URLs that point to directories
-            # normcase helpfully translates path separators for us on Windows
-            if url.startswith('file://') and os.path.isdir(os.path.normcase(url[7:])):
+            (scheme, netloc, path, params, query, fragment) = urlparse.urlparse(url)
+            if scheme == 'file' and os.path.isdir(urllib.url2pathname(path)):
                 url = urllib.basejoin(url, 'index.html')
 
             resp = urlopen(url)

tests/in dex/README.txt

@@ -0,0 +1,2 @@
+This directory has the odd space in its name in order to test urlquoting and
+dequoting of file:// scheme index URLs.

tests/test_file_scheme_index.py

@@ -1,7 +1,9 @@
+import urllib2
+
 from test_pip import here, reset_env, run_pip, pyversion
 from path import Path
 
-index_url = 'file://' + str(Path(here).abspath/'index').replace('\\', '/')
+index_url = 'file://' + urllib2.quote(str(Path(here).abspath/'in dex').replace('\\', '/'))
 
 def test_install():
     """