Fix failing test on Windows due to path separator

setuptools/tests/test_setuptools.py

@@ -23,7 +23,7 @@ def test_findall(example_source):
 def test_findall_curdir(example_source):
     with example_source.as_cwd():
         found = list(setuptools.findall())
-    expected = ['readme.txt', 'foo/bar.py']
+    expected = ['readme.txt', os.path.join('foo', 'bar.py')]
     assert found == expected