Add platform-specific code to override the home directory to honor bp…

…o-36264. Fixes #2112.

setuptools/tests/test_packageindex.py

@@ -3,6 +3,7 @@
 import sys
 import os
 import distutils.errors
+import platform
 
 from setuptools.extern import six
 from setuptools.extern.six.moves import urllib, http_client
@@ -285,7 +286,13 @@ def test_report(self):
 
 @pytest.fixture
 def temp_home(tmpdir, monkeypatch):
-    monkeypatch.setitem(os.environ, 'HOME', str(tmpdir))
+    key = (
+        'USERPROFILE'
+        if platform.system() == 'Windows' and sys.version_info > (3, 8) else
+        'HOME'
+    )
+
+    monkeypatch.setitem(os.environ, key, str(tmpdir))
     return tmpdir