Related to #13, please allow support for vendorized gems. When using a Continuous Integration server (like Hudson or Jenkins), gems cannot be installed globally for a variety of reasons:

1. The user doesn't have sudo permissions
2. Builds are created dynamically
3. We want to mimic a "true" production scenario (where gems are vendorized)

Note that #13 occurs when you install gems anywhere other than the default path. i.e. specifying --path in the bundle option completely breaks appraisal...

The issue happens because you're shelling out to the system another bundle command here.