Backport test improvements

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

mayan/apps/documents/tests/test_widgets.py

@@ -8,7 +8,7 @@ from .test_models import GenericDocumentTestCase
 class DocumentPageWidgetTestCase(GenericDocumentTestCase):
     def test_document_list_view_document_with_no_pages(self):
         document_thumbnail_widget = DocumentPageThumbnailWidget()
-        self.document.pages.all().delete()
+        self.test_document.pages.all().delete()
         result = document_thumbnail_widget.render(instance=self.document)
 
         self.assertTrue(self.document.get_absolute_url() in result)