Introduce suspenders:accessibility generator

Ported over from #1105

Installs [capybara_accessibility_audit] and
[capybara_accessible_selectors].

`./bin/rails g suspenders:accessibility`

[capybara_accessibility_audit]: https://github.com/thoughtbot/capybara_accessibility_audit
[capybara_accessible_selectors]: https://github.com/citizensadvice/capybara_accessible_selectors

NEWS.md

@@ -1,6 +1,7 @@
 Unreleased
 
 * Remove `suspenders` system executable
+* Introduce `suspenders:accessibility` generator
 
 20230113.0 (January, 13, 2023)
 

README.md

@@ -21,7 +21,14 @@ end
 
 ## Generators
 
-TODO
+### Accessibility
+
+Installs [capybara_accessibility_audit] and [capybara_accessible_selectors]
+
+`./bin/rails g suspenders:accessibility`
+
+  [capybara_accessibility_audit]: https://github.com/thoughtbot/capybara_accessibility_audit
+  [capybara_accessible_selectors]: https://github.com/citizensadvice/capybara_accessible_selectors
 
 ## Contributing
 

lib/generators/suspenders/accessibility_generator.rb

@@ -0,0 +1,15 @@
+module Suspenders
+  module Generators
+    class AccessibilityGenerator < Rails::Generators::Base
+      desc "Installs capybara_accessibility_audit and capybara_accessible_selectors"
+
+      def add_capybara_gems
+        gem_group :test do
+          gem "capybara_accessibility_audit"
+          gem "capybara_accessible_selectors", github: "citizensadvice/capybara_accessible_selectors"
+        end
+        Bundler.with_unbundled_env { run "bundle install" }
+      end
+    end
+  end
+end

test/generators/suspenders/accessibility_generator_test.rb

@@ -0,0 +1,61 @@
+require "test_helper"
+require "generators/suspenders/accessibility_generator"
+
+module Suspenders
+  module Generators
+    class AccessibilityGeneratorTest < Rails::Generators::TestCase
+      include Suspenders::TestHelpers
+
+      tests Suspenders::Generators::AccessibilityGenerator
+      destination Rails.root
+      setup :prepare_destination
+      teardown :restore_destination
+
+      test "generator runs without errors" do
+        assert_nothing_raised do
+          run_generator
+        end
+      end
+
+      test "adds gems to Gemfile" do
+        expected_output = <<~RUBY
+          group :test do
+            gem "capybara_accessibility_audit"
+            gem "capybara_accessible_selectors", github: "citizensadvice/capybara_accessible_selectors"
+          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_capybara_gems
+        end
+      end
+
+      test "generator has a description" do
+        description = "Installs capybara_accessibility_audit and capybara_accessible_selectors"
+
+        assert_equal description, Suspenders::Generators::AccessibilityGenerator.desc
+      end
+
+      private
+
+      def prepare_destination
+        touch "Gemfile"
+      end
+
+      def restore_destination
+        remove_file_if_exists "Gemfile"
+      end
+    end
+  end
+end