Add Test Docs

[nsryan2]

The docs from #158 do not include documentation for the tests in scripts/tests. This issue can be closed when those tests are documented, and instructions on how to run the tests is added.

[nsryan2]

Step 1:
Make sure all of the test functions have docstrings.
Step 2:
Make a folder called test_docs inside docs
Step 3:
Make a test_script.rst for each test script
Step 4:
Copy the first two parts of https://github.com/arfc/transition-scenarios/blob/master/docs/index.md?plain=1 and paste into a new file called test_index.rst
Step 5:
Update all the names for the test scripts
Step 6:
Add test_index.rst to index.md