diff --git a/amplpy/tests/test_environment.py b/amplpy/tests/test_environment.py
index 7758779..2cf23e4 100644
--- a/amplpy/tests/test_environment.py
+++ b/amplpy/tests/test_environment.py
@@ -23,6 +23,8 @@ def test_environment_initialization(self):
     def test_environment(self):
         from amplpy import Environment, AMPL
 
+        os.environ["PYTHONIOENCODING"] = "utf-8"
+
         env1 = Environment()
         env2 = Environment(os.curdir)
         self.assertEqual(env2.get_bin_dir(), os.curdir)