Introduce 'suspenders:stylelint` generator

- Assumes we are using `.css` files based on #1146
- Improve test helper
- Configure eslint
- Configure prettier
- Capture yarn warnings

lib/generators/suspenders/stylelint_generator.rb

@@ -0,0 +1,41 @@
+module Suspenders
+  module Generators
+    class StylelintGenerator < Rails::Generators::Base
+      source_root File.expand_path("../../templates/stylelint", __FILE__)
+
+      def install_dependencies
+        run "yarn add stylelint eslint @thoughtbot/stylelint-config @thoughtbot/eslint-config --dev"
+      end
+
+      def configure_stylelint
+        copy_file "stylelintrc.json", ".stylelintrc.json"
+      end
+
+      def configure_eslint
+        copy_file "eslintrc.json", ".eslintrc.json"
+      end
+
+      def configure_prettier
+        copy_file "prettierrc", ".prettierrc"
+      end
+
+      # TODO: Consider extracting this into Rails
+      def update_package_json
+        content = File.read package_json
+        json = JSON.parse content
+        json["scripts"] ||= {}
+
+        json["scripts"]["eslint"] = "npx eslint 'app/javascript/**/*.js'"
+        json["scripts"]["stylelint"] = "npx stylelint 'app/assets/stylesheets/**/*.css'"
+
+        File.write package_json, JSON.pretty_generate(json)
+      end
+
+      private
+
+      def package_json
+        Rails.root.join("package.json")
+      end
+    end
+  end
+end

lib/generators/templates/stylelint/eslint.json

@@ -0,0 +1,6 @@
+{
+  "extends": [
+    "@thoughtbot/eslint-config/base",
+    "@thoughtbot/eslint-config/prettier"
+  ]
+}

lib/generators/templates/stylelint/eslintrc.json

@@ -0,0 +1,6 @@
+{
+  "extends": [
+    "@thoughtbot/eslint-config/base",
+    "@thoughtbot/eslint-config/prettier"
+  ]
+}

lib/generators/templates/stylelint/prettierrc

@@ -0,0 +1,3 @@
+{
+  "singleQuote": true
+}

lib/generators/templates/stylelint/stylelintrc.json

@@ -0,0 +1,3 @@
+{
+  "extends": "@thoughtbot/stylelint-config"
+}

test/generators/suspenders/stylelint_generator_test.rb

@@ -0,0 +1,133 @@
+require "test_helper"
+require "generators/suspenders/stylelint_generator"
+
+module Suspenders
+  module Generators
+    class StylelintGeneratorTest < Rails::Generators::TestCase
+      include Suspenders::TestHelpers
+
+      tests Suspenders::Generators::StylelintGenerator
+      destination Rails.root
+      setup :prepare_destination
+      teardown :restore_destination
+
+      test "installs dependencies" do
+        output = capture(:stderr) { run_generator }
+
+        assert_match(/yarn add stylelint eslint @thoughtbot\/stylelint-config @thoughtbot\/eslint-config --dev/, output)
+      end
+
+      test "configures stylelint" do
+        expected_content = <<~TEXT
+          {
+            "extends": "@thoughtbot/stylelint-config"
+          }
+        TEXT
+
+        capture(:stderr) { run_generator }
+
+        assert_file app_root(".stylelintrc.json") do |file|
+          assert_equal expected_content, file
+        end
+      end
+
+      test "configures eslint" do
+        expected_content = <<~TEXT
+          {
+            "extends": [
+              "@thoughtbot/eslint-config/base",
+              "@thoughtbot/eslint-config/prettier"
+            ]
+          }
+        TEXT
+
+        capture(:stderr) { run_generator }
+
+        assert_file app_root(".eslintrc.json") do |file|
+          assert_equal expected_content, file
+        end
+      end
+
+      test "configures prettier" do
+        expected_content = <<~TEXT
+          {
+            "singleQuote": true
+          }
+        TEXT
+
+        capture(:stderr) { run_generator }
+
+        assert_file app_root(".prettierrc") do |file|
+          assert_equal expected_content, file
+        end
+      end
+
+      test "updates package.json" do
+        touch "package.json", content: package_json
+
+        capture(:stderr) { run_generator }
+
+        assert_file "package.json" do |file|
+          assert_equal expected_package_json, file
+        end
+      end
+
+      test "updates package.json if script key does not exist" do
+        touch "package.json", content: package_json(empty: true)
+
+        capture(:stderr) { run_generator }
+
+        assert_file "package.json" do |file|
+          assert_equal expected_package_json, file
+        end
+      end
+
+      test "description" do
+        skip
+      end
+
+      private
+
+      def prepare_destination
+        touch "Gemfile"
+        touch "package.json", content: package_json(empty: true)
+      end
+
+      def restore_destination
+        remove_file_if_exists "Gemfile"
+        remove_file_if_exists ".stylelintrc.json"
+        remove_file_if_exists ".eslintrc.json"
+        remove_file_if_exists ".prettierrc"
+        remove_file_if_exists "package.json"
+        remove_file_if_exists "package.json", root: true
+        remove_file_if_exists "yarn.lock", root: true
+      end
+
+      def package_json(empty: false)
+        if empty
+          <<~JSON.chomp
+            {
+            }
+          JSON
+        else
+          <<~JSON.chomp
+            {
+              "scripts": {}
+            }
+          JSON
+        end
+      end
+
+      def expected_package_json
+        <<~JSON.chomp
+          {
+            "scripts": {
+              "eslint": "npx eslint 'app/javascript/**/*.js'",
+              "stylelint": "npx stylelint 'app/assets/stylesheets/**/*.css'"
+            }
+          }
+        JSON
+      end
+    end
+  end
+end

test/test_helper.rb

@@ -38,10 +38,15 @@ def mkdir(dir)
     FileUtils.mkdir path
   end
 
-  def touch(file)
+  def touch(file, **options)
+    content = options[:content]
     path = app_root file
 
     FileUtils.touch path
+
+    if content
+      File.write app_root(path), content
+    end
   end
 
   def within_api_only_app(**options, &block)