1 files changed, 52 insertions, 0 deletions
diff --git a/setuptools/tests/test_namespaces.py b/setuptools/tests/test_namespaces.py
new file mode 100644
index 00000000..28c5e9de
--- /dev/null
+++ b/setuptools/tests/test_namespaces.py
@@ -0,0 +1,52 @@
+from __future__ import absolute_import, unicode_literals
+
+import os
+import sys
+import subprocess
+
+import pytest
+
+from . import namespaces
+
+
+class TestNamespaces:
+
+    @pytest.mark.xfail(sys.version_info < (3, 3),
+        reason="Requires PEP 420")
+    @pytest.mark.skipif(bool(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
+        to a site dir and the other installed just to a path on PYTHONPATH
+        should leave the namespace in tact and both packages reachable by
+        import.
+        """
+        pkg_A = namespaces.build_namespace_package(tmpdir, 'myns.pkgA')
+        pkg_B = namespaces.build_namespace_package(tmpdir, 'myns.pkgB')
+        site_packages = tmpdir / 'site-packages'
+        path_packages = tmpdir / 'path-packages'
+        targets = site_packages, path_packages
+        python_path = os.pathsep.join(map(str, targets))
+        # use pip to install to the target directory
+        install_cmd = [
+            'pip',
+            'install',
+            str(pkg_A),
+            '-t', str(site_packages),
+        ]
+        subprocess.check_call(install_cmd)
+        namespaces.make_site_dir(site_packages)
+        install_cmd = [
+            'pip',
+            'install',
+            str(pkg_B),
+            '-t', str(path_packages),
+        ]
+        subprocess.check_call(install_cmd)
+        try_import = [
+            sys.executable,
+            '-c', 'import myns.pkgA; import myns.pkgB',
+        ]
+        env = dict(PYTHONPATH=python_path)
+        subprocess.check_call(try_import, env=env)