rails-test-pipeline provides a structure for setting up automated tests using RSpec and MiniTest for rails on github.

$ rails new my-rails-app --database=postgresql
$ cd my-rails-app
$ rails db:create

$ git add .
$ git commit -m "rails new"
$ gh repo create
$ git push origin master

Follow the rspec documentation to add and install the rspec gem rspec/rspec-rails

# Gemfile
group :development, :test do
  gem 'rspec-rails', '~> 5.0.0'
end

$ bundle install
$ rails generate rspec:install
$ rails db:migrate && rails db:test:prepare

Install the launchy gem In Gemfile

group :test do
  # [...]
  gem 'launchy'
end

$ bundle install

In test/test_helper.rb include and capybara headless chrome for imitating user behaviour without opening a browser. There are several additional helpers like e.g. devise warden (for testing applications with login functionality), which you might add later.

class ActiveSupport::TestCase
  # [...]
end

Capybara.register_driver :headless_chrome do |app|
  options = Selenium::WebDriver::Chrome::Options.new(args: %w[no-sandbox headless disable-gpu window-size=1400,900])
  Capybara::Selenium::Driver.new(app, browser: :chrome, options: options)
end
Capybara.save_path = Rails.root.join('tmp/capybara')
Capybara.javascript_driver = :headless_chrome

Set up Browser tests in test/application_system_test_case.rb

require "test_helper"

# Make sure drivers dont fail under parallel testing
Webdrivers::Chromedriver.update

class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
  driven_by :headless_chrome # Update this line
end

Make Debugging easier by adding config/environments/test.rb

Rails.application.configure do
  # [ ... ]
  config.action_dispatch.show_exceptions = true # Update this line
  # [ ... ]
end

Github Actions will build a test environment and run unit/system tests on every push or pull request.

1. Add the file .github/workflows/test.yml in root directory and copy the script to build and run tests from here
2. Make sure you have your ruby version defined in .ruby-version. In this example its 2.6.6
3. Add the file config/database.github.yml in root directory and copy config for the test database environment from here.
4. Optional - Make passing all tests mandatory in order to merge code into master: In your repo go to Settings/Branches and Add rule and activate Require status checks to pass before merging as well as your test.

The Github Action will automatically run unit tests with $ bundle exec rspec and system tests with $ bundle exec rails test:system. Lets write some tests.

Write unit tests with RSpec to test your models.

As an example lets build the model Tree

$ rails g model Tree age:integer # automatically creates spec/models/tree_spec.rb
$ rails db:migrate

Lets write a simple test for creating a Tree instance and its age accessor. In spec/models/tree_spec.rb write

require 'rails_helper'

describe Tree, type: :model do
  it 'creates a Tree instance with an age' do
    tree = Tree.new(age: 13)
    expect(tree.age).to eq(13)
  end
end

Learn more about Rspec. Learn more about how to write good tests

Use System/Integration tests to imitate the core user journey. We are using MiniTest which is included in Rails by default. Keep the amount of system tests low as they are very time costly. We are

Lets take our Tree example from above and create a new system test

$ rails g system_test tree

System tests require an own environment that has a different database than local and production database. Therefore we set up a testing database called fixtures. We can quickly write them in yml in test/fixtures/trees.yml:

apple_tree:
  age: 13
pear_tree:
  age: 10

Write a test in test/system/products_test.rb to test the display of a tree's age in the trees_path

require "application_system_test_case"

class ProductsTest < ApplicationSystemTestCase
  test "visit home page and see headline" do
    visit trees_path
    save_and_open_screenshot # only works with launchy and opens browser to take a screenshot, take in and out like raise
    assert_selector "h1", text: "13"
  end
end

Here is an exmaple of what the test is looking for in the trees_path:

<% @trees.each do |tree| %>
  <h1>tree.age</h1>
<% end %>

Learn more about Minitests here