Improve Package Maintainability (unit tests and cont. integ.)

[cmurray3]

---

This improvement was suggested by one of the extremely helpful reviewers of the paper titled "VeRoViz: A Vehicle Routing Visualization Toolkit" (https://dx.doi.org/10.2139/ssrn.3746037). See also #36, #37, #38, #39, and #40.

---

• Add unit tests. The following links may help:

  • https://realpython.com/python-testing/
  • https://docs.python.org/3/library/unittest.html
  • https://docs.python-guide.org/writing/tests/
  • https://code.visualstudio.com/docs/python/testing

• Incorporate continuous integration suite to run unit tests. Check out the following:

  • https://lab.github.com/githubtraining/github-actions:-continuous-integration

---

The original reviewer comment appears below:

To match the quality of the work, I would suggest a series of unit tests to test the validity of the basic functionality. Along with this, I would like to see a continuous integration suite (GitHub workflows, travisci, ...) to run these unit tests (every time there is a commit to a certain branch, pull request, etc). This is very easy to set up and really helps.