Seeye runs tests on Heroku. Currently only Rails tests are supported. It sets up a "one-off app" using app.json and runs tests with one-off dyno.
After cloning this repo:
$ bundle install
$ HEROKU_API_TOKEN=xx ./bin/seeye https://github.com/jingweno/ruby-rails-sample/tarball/master/ # make sure it has app.json