Configure Travis CI for Ruby on Rails

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In this tutorial I am going to show you how to configure Travis CI to run your Rails' test suite and system tests everytime you push a new change to your repository.

Create a Simple Rail Application

First we'll need to create simple Rail application. Open up your terminal and run the following commands.

1. $ rails new rails-travis-ci-example -d=postgresql
2. $ rails db:create
3. $ rails g scaffold Post title body:text
   • This step will automatically generate tests and system tests.
4. $ rails db:migrate

Configure Rails Application to run System Tests in Travis CI

Rails is configured by default to run system tests in Google Chrome. However, I ran into an issue with Travis CI when it came to running system tests using the default configuration. My solution was to update test/application_system_test_case.rb by declearing :headless_chrome instead of the default :chrome setting.

1. Edit test/application_system_test_case.rb

# test/application_system_test_case.rb
require "test_helper"

class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
  driven_by :selenium, using: :headless_chrome, screen_size: [1400, 1400]
end

1. Run the test suite locally to ensure it works and passes.

$ rails test
$ rails test:system

Configure Travis CI to run the Rails Test Suite and System Tests

Next we need to create a .travis.yml file in order for Travis CI to know how to build our application.

1. Creat a .travis.yml file and add the following:

language: ruby
cache:
  - bundler
  - yarn
services:
  - postgresql
before_install:
  - nvm install --lts
before_script:
  - bundle install --jobs=3 --retry=3
  - yarn
  - bundle exec rake db:create
  - bundle exec rake db:schema:load
script:
  - bundle exec rake test
  - bundle exec rake test:system

Key	Description
os	Sets the build's operating system. Note that we did not add an os key, and are using the default environment
language	Selects the language support used for the build. We select ruby since this is a Rails project
cache	Activates caching content that does not often change in order to speed up the build process. We add bundler and yarn since Rails uses bundler and yarn to managage dependencies.
services	Services to set up and start. We add postgresql since our database is postgresql. You could also add redis.
before_install	Scripts to run before the install stage. We add nvm install --lts to use the latest stable version of Node. This will be needed when we run yarn later.
before_script	Scripts to run before the script stage. This sets up our Rails application. Note that I do not seed the database, since we only care about the test environment. I run bundle install --jobs=3 --retry=3 instead of bundle becuase that's what the documentation recommends.
script	Scripts to run at the script stage. In our case, we just run our tests.

1. Log into Travis CI and navigate to https://travis-ci.org/account/repositories.
2. Search for your repository, and it enabled. If your repository doesn't appear click the Sync account button.
3. Navigate to your project and trigger a build. Alternatively, make a new commit and push to GitHub to trigger a new build.
4. If you're using Heroku you can use GitHub as your deployment method and enable automatic deployments, but have it configured to wait for the CI to pass first.

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Comments

[Juan Vasquez]

The best guide ever this helps me a lot!

I'm starting an open-source project about virtual school because of the pandemic
github.com/JuanVqz/my_school

Thank you, bro!

[Steve Polito]

Thanks! I was surprised at the lack of documentation on this, and I figured others would find this helpful.

[Alessio Saltarin]

Thank you. I forgot to install Node...

before_install:

• nvm install --lts