Fix test failure on Python 2

wolframalpha/test_client.py

@@ -4,6 +4,8 @@ from __future__ import unicode_literals
 
 import os
 
+import six
+
 import pytest
 
 import wolframalpha
@@ -68,7 +70,7 @@ def test_properties(temp_result):
 def test_pod_attributes(temp_result):
 	pod = next(temp_result.pods)
 	assert isinstance(pod.position, float)
-	assert isinstance(pod.id, str)
+	assert isinstance(pod.id, six.text_type)
 	assert isinstance(pod.subpod[0].img[0].height, int)