Rails6にRSpec、FactoryBot、DatabaseCleanerを導入する

group :development, :test do
  ...省略...

  gem 'database_cleaner-active_record'
  gem 'factory_bot_rails'
  gem 'rspec-rails', '~> 4.0.1'
end

bundle install

bundle exec rails generate rspec:install
      create  .rspec
      create  spec
      create  spec/spec_helper.rb
      create  spec/rails_helper.rb

RSpec.configure do |config|
  ...省略...

  config.include FactoryBot::Syntax::Methods

  config.before(:suite) do
    DatabaseCleaner.strategy = :transaction
    DatabaseCleaner.clean_with(:truncation)
  end

  config.before(:each) do
    DatabaseCleaner.start
  end

  config.after(:each) do
    DatabaseCleaner.clean
  end
end