Support utf 8 (#679)

Author: claudiachua

tests/unit/twiml/__init__.py

@@ -50,3 +50,11 @@ def test_lower_camel_multi_word_mixed_case(self):
 
     def test_lower_camel_camel_cased(self):
         self.assertEqual("fooBar", lower_camel("fooBar"))
+
+    def test_utf8_encoding(self):
+        t = TwiML()
+        t.value = "An utf-8 character: ñ"
+        self.assertEqual(
+            t.to_xml(),
+            '<?xml version="1.0" encoding="UTF-8"?><TwiML>An utf-8 character: ñ</TwiML>',
+        )

tests/unit/twiml/test_voice_response.py

@@ -71,7 +71,7 @@ def test_say_french(self):
 
         assert (
             self.strip(r)
-            == '<?xml version="1.0" encoding="UTF-8"?><Response><Say>n&#233;cessaire et d\'autres</Say></Response>'
+            == '<?xml version="1.0" encoding="UTF-8"?><Response><Say>nécessaire et d\'autres</Say></Response>'
         )
 
     def test_say_loop(self):

twilio/twiml/__init__.py

@@ -64,7 +64,7 @@ def to_xml(self, xml_declaration=True):
 
         :param bool xml_declaration: Include the XML declaration. Defaults to True
         """
-        xml = ET.tostring(self.xml()).decode("utf-8")
+        xml = ET.tostring(self.xml(), encoding="utf-8").decode("utf-8")
         return (
             '<?xml version="1.0" encoding="UTF-8"?>{}'.format(xml)
             if xml_declaration