Update test according to new layout

Separate method making request from TestCase
and into separate TestMixins classes.

Signed-off-by: Roberto Rosario <roberto.rosario@mayan-edms.com>

mayan/apps/document_indexing/tests/mixins.py

@@ -13,7 +13,8 @@ class IndexTestMixin(object):
         self.test_index = Index.objects.create(label=TEST_INDEX_LABEL)
 
         # Add our document type to the new index
-        self.test_index.document_types.add(self.test_document_type)
+        if hasattr(self, 'test_document_type'):
+            self.test_index.document_types.add(self.test_document_type)
 
         # Rebuild indexes
         if rebuild: