[Deradon]

For ruby projects where I could simply put the "new test" in a new file I do this:

1. Create new test (e.g. "spec/reproduce-bug_spec.rb")

2. Ignore it locally: `echo "spec/reproduce_bug_spec.rb" >> .git/info/exclude`

3. Run bisect (something like: `git bisect run rspec spec/reproduce-bug_spec.rb`)

If running the test gets more complex (e.g. installing dependencies as they might change travelling through history), I usually create a wrapper script (and ignore it) to bisect-run-it.