You don't want to use `bundle exec` here as bundler, at run time, adds about a half second.  Instead you want to just use `bin/rspec`; that uses bundler's `--standalone` option, which avoids the bundler tax by not loading bundler at runtime (while still leveraging it to make sure the load paths all get setup correctly so that right version of everything is used).  I've [blogged about it](http://myronmars.to/n/dev-blog/2012/03/faster-test-boot-times-with-bundler-standalone) if you're not familiar.

The travis build is already setup to leverage `--standalone`:

* https://github.com/rspec/rspec-core/blob/0029d5c069e6981a74087a41ac7476ab05f849d8/.travis.yml#L3
* https://github.com/rspec/rspec-core/blob/0029d5c069e6981a74087a41ac7476ab05f849d8/script/test_all#L37


```
➜  rspec-mocks git:(master) time bundle exec rspec -fp &>/dev/null
bundle exec rspec -fp &> /dev/null  2.03s user 0.25s system 99% cpu 2.297 total
➜  rspec-mocks git:(master) time bin/rspec -fp &>/dev/null
bin/rspec -fp &> /dev/null  1.64s user 0.14s system 99% cpu 1.792 total
```