test: fix test setup helpers

[kelly-sovacool]

Changes

• Tests were failing due to outdated helper scripts.
• Add script to run tests locally on macOS via podman.

Issues

NA

PR Checklist

(Strikethrough any points that are not applicable.)

• This comment contains a description of changes with justifications, with any relevant issues linked.
• Run the capsule in Code Ocean and ensure it completes successfully with no errors.
• Update CHANGELOG.md with a short description of any user-facing changes and reference the PR number. Follow the style described in https://style.tidyverse.org/news.html
• The tests workflow succeeds on the latest commit.