attempt at failing test for #2556

This is an attempt at a failing test for #2556 .  I say "attempt" because although I can get a failure on the command line with this setup, I can't make it fail programmatically.

When run on the command-line, `installOne` is going into the `localLink` branch, which causes the failure.

However in the attached unit test, `installOne` just succeeds without going into the link branch.

Output of a successful test run and a failed command-line run in this gist: https://gist.github.com/smikes/daf021d1eb588536bad5