Copilot noted in #4148 (comment) that most of the stubs for getCommitOid weren't correctly set up: the broken stubs assumed that getCommitOid only had one parameter for the ref, while it actually has two for checkoutPath and ref. This meant that calls to the stubbed getCommitOid weren't working as intended and always received undefined.

This PR updates the tests to stub getCommitOid correctly so that the tests work as intended. It also adds test assertions to verify that getCommitOid is called the expected number of times and with the expected arguments.

Risk assessment

For internal use only. Please select the risk level of this change:

• Low risk: Changes are fully under feature flags, or have been fully tested and validated in pre-production environments and are highly observable, or are documentation or test only.

Which use cases does this change impact?

• Testing/None - This change does not impact any CodeQL workflows in production.

How did/will you validate this change?

• Unit tests - I am depending on unit test coverage (i.e. tests in .test.ts files).

If something goes wrong after this change is released, what are the mitigation and rollback strategies?

• Development/testing only - This change cannot cause any failures in production.

How will you know if something goes wrong after this change is released?

Changes are for tests only and will not be released.

Are there any special considerations for merging or releasing this change?

• No special considerations - This change can be merged at any time.

Merge / deployment checklist

• Confirm this change is backwards compatible with existing workflows.
• Consider adding a changelog entry for this change.
• Confirm the readme and docs have been updated if necessary.