Should include more tests to verify functionality

[carlhiggs]

Is your feature request related to a problem? Please describe.
Currently when merging pull requests a Github Actions workflow pulls the Docker image and tests loading the project setup script (subprocesses/ghsci.py).

Describe the solution you'd like
More tests should be run, to confirm the example workflow runs as intended following changes.

This should be relatively straightforward now that the workflow can be run programmatically in Python, so could be evaluated across a series of unit tests.