Add test to ensure an error is raised due to choice duplicates

- Duplicate choice values are no longer allowed in PyXForm.
  More info: XLSForm/pyxform#23
- Rename new_cascading_select.xls to duplicate_choice_form.xls
- Replace choice_filter.xls file with choice_filter.xlsx; Duplicate of
  choice_filter.xls with allow_duplicate_choices setting

onadata/apps/api/tests/viewsets/test_floip_viewset.py

@@ -193,7 +193,7 @@ def test_publish_number_question_names(self):  # pylint: disable=C0103
             self.assertEqual(response.status_code, 400)
             self.assertEqual(response['Content-Type'],
                              'application/vnd.api+json')
-            self.assertIn(u"The name '1448506769745_42' is an invalid xml tag",
+            self.assertIn(u"The name '1448506769745_42' is an invalid XML tag",
                           response.data['text'])
 
     def test_responses_endpoint_format(self):

onadata/apps/main/tests/test_form_errors.py

@@ -100,3 +100,24 @@ def test_spaced_xlsform(self):
         self.assertRaisesMessage(
             PyXFormError, msg, self._publish_xls_file, xls_path)
         self.assertEquals(XForm.objects.count(), count)
+
+    def test_choice_duplicate_error(self):
+        """
+        Test that the choice duplicate error is raised if
+        the "allow_choice_duplicates" setting is not set in the
+        forms settings sheet
+        """
+        count = XForm.objects.count()
+        xls_path = os.path.join(
+            self.this_directory, 'fixtures', 'cascading_selects',
+            'duplicate_choice_form.xls')
+        msg = ("There does not seem to be"
+               " a `allow_choice_duplicates`"
+               " column header defined in your settings sheet."
+               " You must have set `allow_choice_duplicates`"
+               " setting in your settings sheet"
+               " to have duplicate choice list names"
+               " in your choices sheet")
+        self.assertRaisesMessage(
+            PyXFormError, msg, self._publish_xls_file, xls_path)
+        self.assertEquals(XForm.objects.count(), count)

onadata/libs/tests/utils/test_export_builder.py

@@ -836,6 +836,10 @@ def test_zipped_sav_export_with_duplicate_name_in_choice_list(self):
         |         | animals   | 6    | Other      | # <--- duplicate name
         |         | animals   | 8    | None       |
         |         | animals   | 9    | Don't Know |
+
+        | settings |                         |
+        |          | allow_choice_duplicates |
+        |          | Yes                     |
         """
         survey = self.md_to_pyxform_survey(md, {'name': 'exp'})
         data = [{"q1": "1",
@@ -2185,7 +2189,7 @@ def test_select_multiples_choices(self):
 
     def test_select_multiples_choices_with_choice_filter(self):
         survey = create_survey_from_xls(_logger_fixture_path(
-            'choice_filter.xls'
+            'choice_filter.xlsx'
         ))
         dd = DataDictionary()
         dd._survey = survey