Use UTF-8 in setuptools/tests/test_easy_install.py

Author: abravalheri

setuptools/tests/test_easy_install.py

@@ -361,7 +361,7 @@ def test_many_pth_distributions_merge_together(self, tmpdir):
 
 @pytest.fixture
 def setup_context(tmpdir):
-    with (tmpdir / 'setup.py').open('w') as f:
+    with (tmpdir / 'setup.py').open('w', encoding="utf-8") as f:
         f.write(SETUP_PY)
     with tmpdir.as_cwd():
         yield tmpdir