Throw exception on appending non-TwiML

jingming · jingming · commit 664c1fbc33ca · 2017-03-07T10:21:33.000-08:00
diff --git a/tests/unit/twiml/__init__.py b/tests/unit/twiml/__init__.py
@@ -1,8 +1,16 @@
 import unittest
 
+from nose.tools import raises
 from six import text_type
 
+from twilio.twiml import TwiMLException, TwiML
+
 
 class TwilioTest(unittest.TestCase):
     def strip(self, xml):
         return text_type(xml)
+
+    @raises(TwiMLException)
+    def test_append_fail(self):
+        t = TwiML()
+        t.append('foobar')
diff --git a/twilio/twiml/__init__.py b/twilio/twiml/__init__.py
@@ -9,6 +9,10 @@ def lower_camel(string):
     return result[0].lower() + result[1:]
 
 
+class TwiMLException(Exception):
+    pass
+
+
 class TwiML(object):
     """
     Twilio basic verb object.
@@ -50,7 +54,23 @@ def to_xml(self, xml_declaration=True):
         else:
             return xml
 
+    def append(self, verb):
+        """
+        Add a TwiML doc
+        :param verb: TwiML Document
+        :return:
+        """
+        if not isinstance(verb, TwiML):
+            raise TwiMLException()
+
+        self.verbs.append(verb)
+        return self
+
     def xml(self):
+        """
+        Convert to XML
+        :return: Generated TwiML
+        """
         el = ET.Element(self.name)
 
         keys = self.attrs.keys()
@@ -70,7 +90,3 @@ def xml(self):
             el.append(verb.xml())
 
         return el
-
-    def append(self, verb):
-        self.verbs.append(verb)
-        return self
