Introduce suspenders:rake generator

Closes #1138
Closes #1143

Consolidates logic from the existing [advisories][] and [lint][]
generators to create a default Rake task that audits and lints the
codebase.

We do this because it's simpler to bundle this configuration together,
rather than have two separate generators compete to modify the default
Rake task, since those generators can be run independently.

[advisories]: https://github.com/thoughtbot/suspenders/blob/main/lib/suspenders/generators/advisories_generator.rb
[lint]: https://github.com/thoughtbot/suspenders/blob/main/lib/suspenders/generators/lint_generator.rb

NEWS.md

@@ -3,6 +3,7 @@ Unreleased
 * Remove `suspenders` system executable
 * Introduce `suspenders:accessibility` generator
 * Introduce `Suspenders::Generators::APIAppUnsupported` module and concern
+* Introduce `suspenders:rake` generator
 
 20230113.0 (January, 13, 2023)
 

README.md

@@ -30,6 +30,16 @@ Installs [capybara_accessibility_audit] and [capybara_accessible_selectors]
   [capybara_accessibility_audit]: https://github.com/thoughtbot/capybara_accessibility_audit
   [capybara_accessible_selectors]: https://github.com/citizensadvice/capybara_accessible_selectors
 
+### Rake
+
+Configures the default Rake task to audit and lint the codebase with
+[bundler-audit][] and [standard][].
+
+`/bin/rails g suspenders:rake`
+
+  [bundler-audit]: https://github.com/rubysec/bundler-audit
+  [standard]: https://github.com/standardrb/standard
+
 ## Contributing
 
 See the [CONTRIBUTING] document.

lib/generators/suspenders/rake_generator.rb

@@ -0,0 +1,25 @@
+module Suspenders
+  module Generators
+    class RakeGenerator < Rails::Generators::Base
+      source_root File.expand_path("../../templates/rake", __FILE__)
+      desc(<<~TEXT)
+        Configures the default Rake task to audit and lint the codebase with `bundler-audit` and `standard`.
+      TEXT
+
+      def add_bundler_audit_and_standard
+        gem_group :development, :test do
+          gem "bundler-audit", ">= 0.7.0", require: false
+          gem "standard"
+        end
+        Bundler.with_unbundled_env { run "bundle install" }
+      end
+
+      def configurea_rake_task
+        copy_file "bundler_audit.rake", "lib/tasks/bundler_audit.rake"
+
+        insert_into_file "Rakefile", "\nrequire \"standard/rake\"", after: "require_relative \"config/application\""
+        append_file "Rakefile", %(\ntask default: %i[bundle:audit standard]\n)
+      end
+    end
+  end
+end

lib/generators/templates/rake/bundler_audit.rake

@@ -0,0 +1,4 @@
+if Rails.env.development? || Rails.env.test?
+  require "bundler/audit/task"
+  Bundler::Audit::Task.new
+end

test/generators/suspenders/rake_generator_test.rb

@@ -0,0 +1,99 @@
+require "test_helper"
+require "generators/suspenders/rake_generator"
+
+module Suspenders
+  module Generators
+    class RakeGeneratorTest < Rails::Generators::TestCase
+      include Suspenders::TestHelpers
+
+      tests Suspenders::Generators::RakeGenerator
+      destination Rails.root
+      setup :prepare_destination
+      teardown :restore_destination
+
+      test "adds gems to Gemfile" do
+        expected_output = <<~RUBY
+          group :development, :test do
+            gem "bundler-audit", ">= 0.7.0", require: false
+            gem "standard"
+          end
+        RUBY
+
+        run_generator
+
+        assert_file app_root("Gemfile") do |file|
+          assert_match(expected_output, file)
+        end
+      end
+
+      test "installs gems with Bundler" do
+        Bundler.stubs(:with_unbundled_env).yields
+        generator.expects(:run).with("bundle install").once
+
+        capture(:stdout) do
+          generator.add_bundler_audit_and_standard
+        end
+      end
+
+      test "creates custom Rake task" do
+        expected_rake_task = <<~RUBY
+          if Rails.env.development? || Rails.env.test?
+            require "bundler/audit/task"
+            Bundler::Audit::Task.new
+          end
+        RUBY
+
+        run_generator
+
+        assert_file app_root("lib/tasks/bundler_audit.rake") do |file|
+          assert_match expected_rake_task, file
+        end
+      end
+
+      test "modifies existing Rakefile" do
+        rakefile = <<~RUBY
+          require_relative "config/application"
+
+          Rails.application.load_tasks
+        RUBY
+        File.open(app_root("Rakefile"), "w") { _1.write rakefile }
+
+        expected_rakefile = <<~RUBY
+          require_relative "config/application"
+          require "standard/rake"
+
+          Rails.application.load_tasks
+
+          task default: %i[bundle:audit standard]
+        RUBY
+
+        run_generator
+
+        assert_file app_root("Rakefile") do |file|
+          assert_equal expected_rakefile, file
+        end
+      end
+
+      test "generator has a description" do
+        description = <<~TEXT
+          Configures the default Rake task to audit and lint the codebase with `bundler-audit` and `standard`.
+        TEXT
+
+        assert_equal description, generator_class.desc
+      end
+
+      private
+
+      def prepare_destination
+        touch "Gemfile"
+        backup_file "Rakefile"
+      end
+
+      def restore_destination
+        remove_file_if_exists "Gemfile"
+        remove_file_if_exists "lib/tasks/bundler_audit.rake"
+        restore_file "Rakefile"
+      end
+    end
+  end
+end

test/test_helper.rb

@@ -68,8 +68,6 @@ class Application < Rails::Application
     restore_file "config/application.rb"
   end
 
-  private
-
   def backup_file(file)
     FileUtils.mv app_root(file), app_root("#{file}.bak")
     touch file