refactored tests to allow the testing of non-MP trees
refactored tests to allow the testing of non-MP trees

tabo/django-treebeard,tabo/django-treebeard,skirsdeda/django-treebeard,skirsdeda/django-treebeard,tabo/django-treebeard,django-treebeard/django-treebeard,skirsdeda/django-treebeard,django-treebeard/django-treebeard,tabo/django-treebeard,django-treebeard/django-treebeard,skirsdeda/django-treebeard