Skip failing test on appveyor until the cause can be uncovered. Ref #851.

2 files changed, 3 insertions, 1 deletions

diff --git a/setuptools/tests/test_namespaces.py b/setuptools/tests/test_namespaces.py
index c148577d..21fd69e7 100644
--- a/setuptools/tests/test_namespaces.py
+++ b/setuptools/tests/test_namespaces.py
@@ -13,6 +13,8 @@ class TestNamespaces:
 
     @pytest.mark.xfail(sys.version_info < (3, 3),
         reason="Requires PEP 420")
+    @pytest.mark.skipif('os.environ.get("APPVEYOR")',
+        reason="https://github.com/pypa/setuptools/issues/851")
     def test_mixed_site_and_non_site(self, tmpdir):
         """
         Installing two packages sharing the same namespace, one installed
diff --git a/tox.ini b/tox.ini
index 6e03aef2..cfb682ee 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,4 +1,4 @@
 [testenv]
 deps=-rtests/requirements.txt
-passenv=APPDATA USERPROFILE HOMEDRIVE HOMEPATH windir
+passenv=APPDATA USERPROFILE HOMEDRIVE HOMEPATH windir APPVEYOR
 commands=python -m pytest {posargs:-rsx}