Added SimpleProperty tests
Added SimpleProperty tests


Former-commit-id: 4165e132ef84bd271c74074adba1e6b9d1f7fa6f
hnunner/PyOpenWorm,openworm/PyOpenWorm,gsarma/PyOpenWorm,gsarma/PyOpenWorm,kaustubhcs/PyOpenWorm,openworm/PyOpenWorm,travs/PyOpenWorm