Bug/horizon test

[kjjarvis]

Small bugfix to original hotfix solution to issue with horizon. Also adding tests for horizon functionality

[github-actions[bot]]

Thank you for opening this PR. Since this is a release branch, the PR must complete the release checklist, below:

• [ ] Check that each new feature has corresponding tests

• [ ] Confirm all dependencies are in the following: requirements.txt, setup.py, the bottom of dev_guide.rst

• [ ] Confirm that all issues associated with the release have been closed (i.e., requirements have been met) or assigned to another release

• [ ] Run unit tests python -m tests

• [ ] If present, run manual tests python -m tests.test_manual

• [ ] Review the template(s)

• [ ] Review static-analysis/linter results

• [ ] Review the tutorial

• [ ] Run and review the examples

• [ ] Check that all examples are tested

• [ ] Check new files in PR for any accidentally added

• [ ] Check documents

  • [ ] Check that all desired examples are in docs

  • [ ] General review: see if any updates are required

• [ ] Rebuild sphinx documents: sphinx-build sphinx_config/ docs/

• [ ] Write release notes

• [ ] Update version number in src/*/init.py and setup.py

• [ ] For releases adding new features- ensure that NASA release process has been followed.

• [ ] Confirm that on GitHub Releases page, the next release has been started and that a schedule is present including at least Release Date, Release Review Date, and Release Branch Opening Date.`