Introduce suspenders:styles generator

Configures applications to use [PostCSS][1] or [Tailwind][2] via
[cssbundling-rails][3]. Defaults to `PostCSS` with
[modern-normalize][8], with the option to override via `--css=tailwind`.
These options were pulled from the [supported list of options][4] in
Rails.

Also creates a directory structure to store additional style sheets if
using PostCSS.

We choose to use [cssbundling-rails][4] instead of [dartsass-rails][5]
or [tailwindcss-rails][6] (or even just css) because we want to rely on
Node to process the CSS. Although we could have chosen to avoid using
Node altogether, we feel it's better to support it since we'll need it
for additional generators, like [StyleLintGenerator][7], and to support
[modern-normalize][8].

Updates `within_api_only_app` by allowing support to conditionally
comment out the api configuration. This provided and opportunity to
clean up existing setup steps.

[1]: https://postcss.org
[2]: https://tailwindcss.com
[3]: https://github.com/rails/cssbundling-rails
[4]: https://github.com/rails/rails/blob/438cad462638b02210fc48b700c29dcd0428a8b7/railties/lib/rails/generators/app_base.rb#L22
[5]: https://github.com/rails/dartsass-rails
[6]: https://github.com/rails/tailwindcss-rails
[7]: https://github.com/thoughtbot/suspenders/blob/main/lib/suspenders/generators/stylelint_generator.rb
[8]: https://github.com/sindresorhus/modern-normalize
[9]: https://tailwindcss.com/docs/functions-and-directives#layer

NEWS.md

@@ -5,6 +5,7 @@ Unreleased
 * Introduce `suspenders:inline_svg` generator
 * Introduce `suspenders:factories` generator
 * Introduce `suspenders:advisories` generator
+* Introduce `suspenders:styles` generator
 
 20230113.0 (January, 13, 2023)
 

README.md

@@ -72,6 +72,22 @@ improvement for the viewer.
 
   [inline_svg]: https://github.com/jamesmartin/inline_svg
 
+### Styles
+
+Configures applications to use [PostCSS][] or [Tailwind][] via
+[cssbundling-rails][]. Defaults to PostCSS with [modern-normalize][], with the
+option to override via `--css=tailwind`.
+
+Also creates a directory structure to store additional stylesheets if using
+PostCSS.
+
+`bin/rails g suspenders:styles --css[postcss:tailwind]`
+
+  [PostCSS]: https://postcss.org
+  [Tailwind]: https://tailwindcss.com
+  [cssbundling-rails]: https://github.com/rails/cssbundling-rails
+  [modern-normalize]: https://github.com/sindresorhus/modern-normalize
+
 ## Contributing
 
 See the [CONTRIBUTING] document.

lib/generators/suspenders/styles_generator.rb

@@ -0,0 +1,64 @@
+module Suspenders
+  module Generators
+    class StylesGenerator < Rails::Generators::Base
+      include Suspenders::Generators::APIAppUnsupported
+
+      CSS_OPTIONS = %w[tailwind postcss].freeze
+
+      class_option :css, enum: CSS_OPTIONS, default: "postcss"
+      desc <<~TEXT
+        Configures applications to use PostCSS or Tailwind via cssbundling-rails.
+        Defaults to PostCSS with modern-normalize, with the option to override via
+        --css=tailwind.
+
+        Also creates a directory structure to store additional stylesheets if using
+        PostCSS.
+      TEXT
+
+      def add_cssbundling_rails_gem
+        gem "cssbundling-rails"
+
+        Bundler.with_unbundled_env { run "bundle install" }
+        run "bin/rails css:install:#{css}"
+      end
+
+      def build_directory_structure
+        return if is_tailwind?
+
+        create_file "app/assets/stylesheets/base.css"
+        create_file "app/assets/stylesheets/components.css"
+        create_file "app/assets/stylesheets/utilities.css"
+      end
+
+      # Remove if https://github.com/rails/cssbundling-rails/pull/139 is merged
+      def configure_application_stylesheet
+        return if is_tailwind?
+
+        run "yarn add modern-normalize"
+
+        append_to_file application_stylesheet do
+          <<~TEXT
+            @import "modern-normalize";
+            @import "base.css";
+            @import "components.css";
+            @import "utilities.css";
+          TEXT
+        end
+      end
+
+      private
+
+      def css
+        @css ||= options["css"]
+      end
+
+      def application_stylesheet
+        "app/assets/stylesheets/application.postcss.css"
+      end
+
+      def is_tailwind?
+        css == "tailwind"
+      end
+    end
+  end
+end

test/generators/suspenders/accessibility_generator_test.rb

@@ -25,11 +25,7 @@ class AccessibilityGeneratorTest < Rails::Generators::TestCase
       end
 
       test "does not raise if API configuration is commented out" do
-        within_api_only_app do
-          path = app_root("config/application.rb")
-          content = File.binread(path).gsub!("config.api_only = true", "# config.api_only = true")
-          File.binwrite(path, content)
-
+        within_api_only_app commented_out: true do
           run_generator
 
           assert_file app_root("Gemfile") do |file|

test/generators/suspenders/inline_svg_generator_test.rb

@@ -24,11 +24,7 @@ class InlinveSvgGeneratorTest < Rails::Generators::TestCase
       end
 
       test "does not raise if API configuration is commented out" do
-        within_api_only_app do
-          path = app_root("config/application.rb")
-          content = File.binread(path).gsub!("config.api_only = true", "# config.api_only = true")
-          File.binwrite(path, content)
-
+        within_api_only_app commented_out: true do
           run_generator
 
           assert_file app_root("Gemfile") do |file|

test/generators/suspenders/styles_generator_test.rb

@@ -0,0 +1,213 @@
+require "test_helper"
+require "generators/suspenders/styles_generator"
+
+module Suspenders
+  module Generators
+    class StylesGenerator::DefaultTest < Rails::Generators::TestCase
+      include Suspenders::TestHelpers
+
+      tests Suspenders::Generators::StylesGenerator
+      destination Rails.root
+      setup :prepare_destination
+      teardown :restore_destination
+
+      test "raises if API only application" do
+        within_api_only_app do
+          assert_raises Suspenders::Generators::APIAppUnsupported::Error do
+            run_generator
+          end
+        end
+      end
+
+      test "does not raise if API configuration is commented out" do
+        within_api_only_app(commented_out: true) do
+          run_generator
+        end
+      end
+
+      test "adds gems to Gemfile" do
+        run_generator
+
+        assert_file app_root("Gemfile") do |file|
+          assert_match "cssbundling-rails", file
+        end
+      end
+
+      test "installs gems with Bundler" do
+        output = run_generator
+
+        assert_match(/bundle install/, output)
+      end
+
+      test "runs install script" do
+        output = run_generator
+
+        assert_match(/bin\/rails css:install:postcss/, output)
+      end
+
+      test "generator has a description" do
+        description = <<~TEXT
+          Configures applications to use PostCSS or Tailwind via cssbundling-rails.
+          Defaults to PostCSS with modern-normalize, with the option to override via
+          --css=tailwind.
+
+          Also creates a directory structure to store additional stylesheets if using
+          PostCSS.
+        TEXT
+
+        assert_equal description, generator_class.desc
+      end
+
+      private
+
+      def prepare_destination
+        touch "Gemfile"
+        touch "app/assets/stylesheets/application.postcss.css"
+      end
+
+      def restore_destination
+        remove_file_if_exists "Gemfile"
+        remove_file_if_exists "package.json", root: true
+        remove_file_if_exists "yarn.lock", root: true
+        remove_file_if_exists "app/assets/stylesheets/application.postcss.css"
+        remove_file_if_exists "app/assets/stylesheets/base.css"
+        remove_file_if_exists "app/assets/stylesheets/components.css"
+        remove_file_if_exists "app/assets/stylesheets/utilities.css"
+      end
+    end
+
+    class StylesGenerator::ClassOptionTest < Rails::Generators::TestCase
+      include Suspenders::TestHelpers
+
+      tests Suspenders::Generators::StylesGenerator
+      destination Rails.root
+      setup :prepare_destination
+      teardown :restore_destination
+
+      test "has a css option" do
+        option = generator_class.class_options[:css]
+
+        assert_equal :string, option.type
+        assert_not option.required
+        assert_equal %w[tailwind postcss], option.enum
+        assert_equal "postcss", option.default
+      end
+
+      test "raises if css option is unsupported" do
+        output = capture(:stderr) { run_generator %w[--css=unknown] }
+
+        assert_match(/Expected '--css' to be one of/, output)
+      end
+
+      private
+
+      def prepare_destination
+        touch "Gemfile"
+      end
+
+      def restore_destination
+        remove_file_if_exists "Gemfile"
+        remove_file_if_exists "package.json", root: true
+        remove_file_if_exists "yarn.lock", root: true
+        remove_file_if_exists "app/assets/stylesheets/application.postcss.css"
+        remove_file_if_exists "app/assets/stylesheets/base.css"
+        remove_file_if_exists "app/assets/stylesheets/components.css"
+        remove_file_if_exists "app/assets/stylesheets/utilities.css"
+      end
+    end
+
+    class StylesGenerator::TailwindTest < Rails::Generators::TestCase
+      include Suspenders::TestHelpers
+
+      tests Suspenders::Generators::StylesGenerator
+      destination Rails.root
+      setup :prepare_destination
+      teardown :restore_destination
+
+      test "runs install script" do
+        output = run_generator %w[--css=tailwind]
+
+        assert_match(/bin\/rails css:install:tailwind/, output)
+      end
+
+      test "does not install normalize" do
+        output = run_generator %w[--css=tailwind]
+
+        assert_no_match(/add.*modern-normalize/, output)
+      end
+
+      test "does not create directory structure" do
+        run_generator %w[--css=tailwind]
+
+        assert_no_file app_root("app/assets/stylesheets/base.css")
+        assert_no_file app_root("app/assets/stylesheets/components.css")
+        assert_no_file app_root("app/assets/stylesheets/utilities.css")
+      end
+
+      private
+
+      def prepare_destination
+        touch "Gemfile"
+      end
+
+      def restore_destination
+        remove_file_if_exists "Gemfile"
+        remove_file_if_exists "package.json", root: true
+        remove_file_if_exists "yarn.lock", root: true
+        remove_file_if_exists "app/assets/stylesheets/base.css"
+        remove_file_if_exists "app/assets/stylesheets/components.css"
+        remove_file_if_exists "app/assets/stylesheets/utilities.css"
+      end
+    end
+
+    class StylesGenerator::PostCssTest < Rails::Generators::TestCase
+      include Suspenders::TestHelpers
+
+      tests Suspenders::Generators::StylesGenerator
+      destination Rails.root
+      setup :prepare_destination
+      teardown :restore_destination
+
+      test "installs normalize and imports style sheets" do
+        output = run_generator %w[--css=postcss]
+        application_stylesheet = <<~TEXT
+          @import "modern-normalize";
+          @import "base.css";
+          @import "components.css";
+          @import "utilities.css";
+        TEXT
+
+        assert_match(/add.*modern-normalize/, output)
+
+        assert_file app_root("app/assets/stylesheets/application.postcss.css") do |file|
+          assert_equal application_stylesheet, file
+        end
+      end
+
+      test "creates directory structure" do
+        run_generator
+
+        assert_file app_root("app/assets/stylesheets/base.css")
+        assert_file app_root("app/assets/stylesheets/components.css")
+        assert_file app_root("app/assets/stylesheets/utilities.css")
+      end
+
+      private
+
+      def prepare_destination
+        touch "Gemfile"
+        touch "app/assets/stylesheets/application.postcss.css"
+      end
+
+      def restore_destination
+        remove_file_if_exists "Gemfile"
+        remove_file_if_exists "package.json", root: true
+        remove_file_if_exists "yarn.lock", root: true
+        remove_file_if_exists "app/assets/stylesheets/application.postcss.css"
+        remove_file_if_exists "app/assets/stylesheets/base.css"
+        remove_file_if_exists "app/assets/stylesheets/components.css"
+        remove_file_if_exists "app/assets/stylesheets/utilities.css"
+      end
+    end
+  end
+end

test/test_helper.rb

@@ -19,8 +19,9 @@ def app_root(path)
     Rails.root.join path
   end
 
-  def remove_file_if_exists(file)
-    path = app_root file
+  def remove_file_if_exists(file, **options)
+    root = options[:root]
+    path = root ? file : app_root(file)
 
     FileUtils.rm path if File.exist? path
   end
@@ -43,7 +44,14 @@ def touch(file)
     FileUtils.touch path
   end
 
-  def within_api_only_app(&block)
+  def within_api_only_app(**options, &block)
+    commented_out = options[:commented_out]
+    set_config = if commented_out == true
+      "# config.api_only = true"
+    else
+      "config.api_only = true"
+    end
+
     backup_file "config/application.rb"
     application_config = <<~RUBY
       require_relative "boot"
@@ -57,7 +65,7 @@ class Application < Rails::Application
 
           config.autoload_lib(ignore: %w(assets tasks))
 
-          config.api_only = true
+          #{set_config}
         end
       end
     RUBY