Unit test reorganization

[aburrell]

Description

Partially addresses issue #58 by:

• Putting related tests into classes
• Adding missing docstrings
• Using parametrize where appropriate
• Expanding tests in some areas

Type of change

Please delete options that are not relevant.

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

Running unit tests locally

Test Configuration:

• Operating system: OS X Mojave
• Python version number: 3.7
• Compiler with version number: gcc9 9.3.0_5
• Any details about your local setup that are relevant: started off of develop branch

Checklist:

• [x] Make sure you are merging into the develop (not main) branch
• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation
• [x] My changes generate no new warnings
• [x] I have added tests that prove my fix is effective or that my feature works
• [x] New and existing unit tests pass locally with my changes
• [x] Any dependent changes have been merged and published in downstream modules
• [x] Add a note to Changelog.rst, summarising the changes
• [x] Add yourself to AUTHORS.rst and .zenodo.json

[coveralls]

Pull Request Test Coverage Report for Build 762

• 5 of 6 (83.33%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+1.5%) to 98.95%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/apexpy/apex.py	5	6	83.33%
<!--	Total:	5	6	83.33%	-->

Totals
Change from base Build 730:	1.5%
Covered Lines:	373
Relevant Lines:	377

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💛 - Coveralls

[aburrell]

Also partially addresses #60

[aburrell]

Also addresses #72