I'm a little uneasy about "stubbing" `getShortHead` and `getUpstreamBranch` here. Personally, I feel more confident with the end-to-end integration-style tests that are used for all the other scenarios in the `describe "open"` context.

For consistency with the other tests, and to provide a better end-to-end integration test, how would you feel about creating two new fixture repos and using those fixtures for these two new tests?

- One where the current local branch has a slash in the name
- One where the current local branch does not have a slash in the name, but its remote tracking branch does have a slash