Section A

大部分写Rails的人都是被手把手的教着TDD、BDD这些东西的，尽管职业生涯中，并没有怎么（几乎没有）为自己的代码写过测试，当然啦，比如写这边文章之前倒是写了一点测试的啦。

Section B

一顿操作猛如虎，当然是先scaffold一个简单的Rails项目啦。

step 1

在这一步你需要安装一些大大小小的依赖，配置环境啦，当然数据库这些无关的 topic 这里就不会在 cover 啦。

rails new testproject && cd testproject && bundle install

在 Gemfile 中添加一些依赖

source 'https://rubygems.org'
git_source(:github) do |repo_name|
  repo_name = "#{repo_name}/#{repo_name}" unless repo_name.include?("/")
  "https://github.com/#{repo_name}.git"
end
# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '~> 5.1.6'
# Use sqlite3 as the database for Active Record
gem 'sqlite3'
# Use Puma as the app server
gem 'puma', '~> 3.7'
# Use SCSS for stylesheets
gem 'sass-rails', '~> 5.0'
# Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'
# See https://github.com/rails/execjs#readme for more supported runtimes
# gem 'therubyracer', platforms: :ruby

# Use CoffeeScript for .coffee assets and views
gem 'coffee-rails', '~> 4.2'
# Turbolinks makes navigating your web application faster. Read more: https://github.com/turbolinks/turbolinks
gem 'turbolinks', '~> 5'
# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
gem 'jbuilder', '~> 2.5'
# Use Redis adapter to run Action Cable in production
# gem 'redis', '~> 4.0'
# Use ActiveModel has_secure_password
# gem 'bcrypt', '~> 3.1.7'

# Use Capistrano for deployment
# gem 'capistrano-rails', group: :development

group :development, :test do
  gem 'rspec-rails', '~> 3.7'
  # Call 'byebug' anywhere in the code to stop execution and get a debugger console
  gem 'byebug', platforms: [:mri, :mingw, :x64_mingw]
  # Adds support for Capybara system testing and selenium driver
  gem 'capybara', '~> 2.13'
  gem 'selenium-webdriver'

  gem "database_cleaner"
  gem 'factory_bot'
  gem 'factory_bot_rails'
end

group :development do
  # Access an IRB console on exception pages or by using <%= console %> anywhere in the code.
  gem 'web-console', '>= 3.3.0'
  gem 'listen', '>= 3.0.5', '< 3.2'
  # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
  gem 'spring'
  gem 'spring-watcher-listen', '~> 2.0.0'
end

# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]

gem 'devise'

在这里我们添加了以下的 Gem （邓紫棋）包。

• devise
• database_cleaner
• factory_bot && factory_bot_rails *（可能涉及女性的都比较敏感，以前叫做 factory_girl）
• rspec
• capybara

step 2

完成上述操作并且 bundle install 之后，接下来就是 install 并且配置。

rails generate rspec:install
# 这里 rspec 会默认生成一些文件夹，但是这里似乎会少了一点我们需要的文件夹比如 `system` 还有 `factories` ，不过可能是我安装的顺序的问题，应该一次性生成是没有问题的
mkdir -p spec/factories
mkdir -p spec/system
touch spec/factories/user_factory.rb
touch system/users_spec.rb

rails generate devise:install User
rails generate devise:views

我们这里只需要简单的 devise 功能，所以并不需要额外的配置。

关键点其实也就是以下 rails_helper 的方法了。

# This file is copied to spec/ when you run 'rails generate rspec:install'
require 'spec_helper'
ENV['RAILS_ENV'] ||= 'test'
require File.expand_path('../../config/environment', __FILE__)
# Prevent database truncation if the environment is production
abort("The Rails environment is running in production mode!") if Rails.env.production?
require 'rspec/rails'
require 'capybara/rspec'
require 'factory_bot'

# Add additional requires below this line. Rails is not loaded until this point!

# Requires supporting ruby files with custom matchers and macros, etc, in
# spec/support/ and its subdirectories. Files matching `spec/**/*_spec.rb` are
# run as spec files by default. This means that files in spec/support that end
# in _spec.rb will both be required and run as specs, causing the specs to be
# run twice. It is recommended that you do not name files matching this glob to
# end with _spec.rb. You can configure this pattern with the --pattern
# option on the command line or in ~/.rspec, .rspec or `.rspec-local`.
#
# The following line is provided for convenience purposes. It has the downside
# of increasing the boot-up time by auto-requiring all files in the support
# directory. Alternatively, in the individual `*_spec.rb` files, manually
# require only the support files necessary.
#
# Dir[Rails.root.join('spec/support/**/*.rb')].each { |f| require f }

# Checks for pending migrations and applies them before tests are run.
# If you are not using ActiveRecord, you can remove this line.
ActiveRecord::Migration.maintain_test_schema!

Capybara.server = :puma

Capybara.register_driver :selenium_chrome do |app|
  Capybara::Selenium::Driver.new(app, browser: :chrome)
end

Capybara.javascript_driver = :selenium_chrome

RSpec.configure do |config|
  # Remove this line if you're not using ActiveRecord or ActiveRecord fixtures
  config.fixture_path = "#{::Rails.root}/spec/fixtures"

  # If you're not using ActiveRecord, or you'd prefer not to run each of your
  # examples within a transaction, remove the following line or assign false
  # instead of true.
  config.use_transactional_fixtures = true

  # RSpec Rails can automatically mix in different behaviours to your tests
  # based on their file location, for example enabling you to call `get` and
  # `post` in specs under `spec/controllers`.
  #
  # You can disable this behaviour by removing the line below, and instead
  # explicitly tag your specs with their type, e.g.:
  #
  #     RSpec.describe UsersController, :type => :controller do
  #       # ...
  #     end
  #
  # The different available types are documented in the features, such as in
  # https://relishapp.com/rspec/rspec-rails/docs
  config.infer_spec_type_from_file_location!

  # Filter lines from Rails gems in backtraces.
  config.filter_rails_from_backtrace!
  # arbitrary gems may also be filtered via:
  # config.filter_gems_from_backtrace("gem name")
  config.include Devise::Test::ControllerHelpers, type: :controller

  config.before(:suite) do
    DatabaseCleaner.clean_with(:truncation)
  end
  config.before(:each) do
    DatabaseCleaner.strategy = :transaction
  end
  config.before(:each, js: true) do
    DatabaseCleaner.strategy = :truncation
  end
  # This block must be here, do not combine with the other `before(:each)` block.
  # This makes it so Capybara can see the database.
  config.before(:each) do
    DatabaseCleaner.start
  end
  config.after(:each) do
    DatabaseCleaner.clean
  end
end

以上需要注意的其实就是 capybara, database_cleaner, factory_bot 的一些代码

step 3

user factory

FactoryBot.define do
  factory :user do
    email "user@example.com"
    password "password"
  end
end

users_spec

require "rails_helper"

RSpec.describe "users spec", :type => :system do
  
  before :each do 
    @user = FactoryBot.create( :user )
  end

  it "sign in" do
    visit "/users/sign_in"

    fill_in "Email", :with => "user@example.com"
    fill_in "Password", :with => "password"

    click_button "Log in"

    expect(page).to have_text("Home")
  end
end

step 4

rspec spec/system

Section C

以上便是一个完整的 Rails 并且带测试的项目咯。