TST Increase coverage for unittest - base objects

[drewejohnson]

Summary of issue

serpentTools/objects/base.py is currently at 32% coverage. I have attached an annotated report using coverage that shows which lines are untested

Code for reproducing the issue

$ git checkout develop
$ git pull
$ python setup.py install
$ coverage run setup.py test
$ coverage report

Generate the html document attached with
$ coverage html

Expected outcome

Get this number up to >70% with extra internet points for 90-100%. Most of this is due to plotting that is not covered by our unittests, but is covered in our testNotebooks.sh script

Versions

• Version from serpentTools.__version__ 0.5.2+15.gb1d86b1 ⬅️ b1d86b1

• Python version - python --version 3.5.2