Add unit tests to supercomputer module

[jmcook1186]

Story

As a user I want to see that the supercomputer module is working as expected. As a developer i want 100% test coverage so I know my changes haven't broken anything.

Rationale

We identified some areas in the graph nesting that weren't well covered by our unit tests and could let some errors go throuhg unchecked. This PR closes those holes.

Implementation details

Add unit tests that fully cover the graph nesting.

Priority

4/5

Scope

unit tests only

Size

1 d

What does "done" look like?

Unit tests with 100% coverage that address corner cases with complicated nesting

Does this require updaes to documentation or other materials??

no docs updates required

What testing is required?

All unit tests passing, 100% coverage

Is this a known/expected update?

known since w/c 08/01/24