Add support for using view components in rails engine (#1951)

* Add module namespacing to generated components and other files

First step to add support for using view components in rails engine

* Config#default_preview_paths should include preview paths generated for rails engine

* Add some dummy tests

* Create test group for engine tests

* Fix test and simplecov setup for engine tests

* Tweak tests

* Allow to run tests with 'm' ;)

* Fix tests

* Improve tests

* Fix preview paths

* Return unique values for default_preview_path

* One step closer with tests

* Remove trailing whitespaces

* Update CHANGELOG

* Update contributors list

* Remove .keep

* Update changelog - be more precise in changes description

* Don't wrap with module namespace in tests and specs

Instead of wraping test/spec with module namespacing
pass module namespace inline with described class

* Rename Dummy => TestEngine

---------

Co-authored-by: Joel Hawksley <joel@hawksley.org>

Rakefile

@@ -8,7 +8,13 @@ require "yard/mattr_accessor_handler"
 Rake::TestTask.new(:test) do |t|
   t.libs << "test"
   t.libs << "lib"
-  t.test_files = FileList["test/**/*_test.rb"]
+  t.test_files = FileList["test/sandbox/**/*_test.rb", "test/view_component/**/*_test.rb"]
+end
+
+Rake::TestTask.new(:engine_test) do |t|
+  t.libs << "test/test_engine"
+  t.libs << "test/test_engine/lib"
+  t.test_files = FileList["test/test_engine/**/*_test.rb"]
 end
 
 begin
@@ -128,4 +134,4 @@ namespace :docs do
   end
 end
 
-task default: :test
+task default: [:test, :engine_test]

docs/CHANGELOG.md

@@ -10,6 +10,10 @@ nav_order: 5
 
 ## main
 
+* Add Rails engine support to generators.
+
+    *Tomasz Kowalewski*
+
 ## 3.14.0
 
 * Defer to built-in caching for language environment setup, rather than manually using `actions/cache` in CI.

docs/index.md

@@ -225,6 +225,7 @@ ViewComponent is built by over a hundred members of the community, including:
 <img src="https://avatars.githubusercontent.com/neanias?s=64" alt="neanias" width="32" />
 <img src="https://avatars.githubusercontent.com/allan-pires?s=64" alt="allan-pires" width="32" />
 <img src="https://avatars.githubusercontent.com/jasonkim?s=64" alt="jasonkim" width="32" />
+<img src="https://avatars.githubusercontent.com/tkowalewski" alt="tkowalewski" width="32" />
 
 ## Who uses ViewComponent?
 

lib/rails/generators/component/templates/component.rb.tt

@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+<% module_namespacing do -%>
 class <%= class_name %>Component < <%= parent_class %>
 <%- if initialize_signature -%>
   def initialize(<%= initialize_signature %>)
@@ -11,5 +12,5 @@ class <%= class_name %>Component < <%= parent_class %>
     content_tag :h1, "Hello world!"<%= ", data: { controller: \"#{stimulus_controller}\" }" if options["stimulus"] %>
   end
 <%- end -%>
-
 end
+<% end -%>

lib/rails/generators/preview/templates/component_preview.rb.tt

@@ -1,7 +1,9 @@
 # frozen_string_literal: true
 
+<% module_namespacing do -%>
 class <%= class_name %>ComponentPreview < ViewComponent::Preview
   def default
     render(<%= class_name %>Component.new<%= "(#{render_signature})" if render_signature %>)
   end
 end
+<% end -%>

lib/rails/generators/rspec/templates/component_spec.rb.tt

@@ -2,7 +2,7 @@
 
 require "rails_helper"
 
-RSpec.describe <%= class_name %>Component, type: :component do
+RSpec.describe <%= namespaced? ? "#{namespace.name}::" : '' %><%= class_name %>Component, type: :component do
   pending "add some examples to (or delete) #{__FILE__}"
 
   # it "renders something useful" do

lib/rails/generators/test_unit/templates/component_test.rb.tt

@@ -2,7 +2,7 @@
 
 require "test_helper"
 
-class <%= class_name %>ComponentTest < ViewComponent::TestCase
+class <%= namespaced? ? "#{namespace.name}::" : '' %><%= class_name %>ComponentTest < ViewComponent::TestCase
   def test_component_renders_something_useful
     # assert_equal(
     #   %(<span>Hello, components!</span>),

lib/view_component/config.rb

@@ -168,11 +168,29 @@ def defaults
       # Defaults to `false`.
 
       def default_preview_paths
+        (default_rails_preview_paths + default_rails_engines_preview_paths).uniq
+      end
+
+      def default_rails_preview_paths
         return [] unless defined?(Rails.root) && Dir.exist?("#{Rails.root}/test/components/previews")
 
         ["#{Rails.root}/test/components/previews"]
       end
 
+      def default_rails_engines_preview_paths
+        return [] unless defined?(Rails::Engine)
+
+        registered_rails_engines_with_previews.map do |descendant|
+          "#{descendant.root}/test/components/previews"
+        end
+      end
+
+      def registered_rails_engines_with_previews
+        Rails::Engine.descendants.select do |descendant|
+          defined?(descendant.root) && Dir.exist?("#{descendant.root}/test/components/previews")
+        end
+      end
+
       def default_generate_options
         options = ActiveSupport::OrderedOptions.new(false)
         options.preview_path = ""

test/sandbox/test/generators/component_generator_test.rb

@@ -16,6 +16,7 @@ def test_component
     run_generator
 
     assert_file "app/components/user_component.rb" do |component|
+      assert_no_match(/module/, component)
       assert_match(/class UserComponent < ViewComponent::Base/, component)
       assert_no_match(/def initialize/, component)
     end
@@ -25,6 +26,7 @@ def test_component_tests
     run_generator %w[user --test-framework test_unit]
 
     assert_file "test/components/user_component_test.rb" do |component|
+      assert_no_match(/module/, component)
       assert_match(/class UserComponentTest < /, component)
       assert_match(/def test_component_renders_something_useful/, component)
     end
@@ -35,6 +37,7 @@ def test_component_preview
       run_generator %w[user --preview]
 
       assert_file "test/components/previews/user_component_preview.rb" do |component|
+        assert_no_match(/module/, component)
         assert_match(/class UserComponentPreview < /, component)
         assert_match(/render\(UserComponent.new\)/, component)
       end
@@ -45,6 +48,7 @@ def test_component_with_arguments
     run_generator %w[user name]
 
     assert_file "app/components/user_component.rb" do |component|
+      assert_no_match(/module/, component)
       assert_match(/class UserComponent < /, component)
       assert_match(/def initialize\(name:\)/, component)
     end
@@ -65,6 +69,7 @@ def test_component_with_parent
     run_generator %w[user --parent MyOtherBaseComponent]
 
     assert_file "app/components/user_component.rb" do |component|
+      assert_no_match(/module/, component)
       assert_match(/class UserComponent < MyOtherBaseComponent/, component)
     end
   end
@@ -74,6 +79,7 @@ def test_component_with_parent_and_application_component_class
       run_generator %w[user --parent MyOtherBaseComponent]
 
       assert_file "app/components/user_component.rb" do |component|
+        assert_no_match(/module/, component)
         assert_match(/class UserComponent < MyOtherBaseComponent/, component)
       end
     end
@@ -84,6 +90,7 @@ def test_component_with_parent_and_custom_component_parent_class
       run_generator %w[user --parent MyOtherBaseComponent]
 
       assert_file "app/components/user_component.rb" do |component|
+        assert_no_match(/module/, component)
         assert_match(/class UserComponent < MyOtherBaseComponent/, component)
       end
     end
@@ -92,13 +99,17 @@ def test_component_with_parent_and_custom_component_parent_class
   def test_component_with_namespace
     run_generator %w[admins/user]
 
-    assert_file "app/components/admins/user_component.rb", /class Admins::UserComponent < /
+    assert_file "app/components/admins/user_component.rb" do |component|
+      assert_no_match(/module/, component)
+      assert_match(/class Admins::UserComponent < /, component)
+    end
   end
 
   def test_component_tests_with_namespace
     run_generator %w[admins/user --test-framework test_unit]
 
     assert_file "test/components/admins/user_component_test.rb" do |component|
+      assert_no_match(/module/, component)
       assert_match(/class Admins::UserComponentTest < /, component)
       assert_match(/def test_component_renders_something_useful/, component)
     end
@@ -142,6 +153,7 @@ def test_generating_components_with_application_component_class
       run_generator %w[user]
 
       assert_file "app/components/user_component.rb" do |component|
+        assert_no_match(/module/, component)
         assert_match(/class UserComponent < ApplicationComponent/, component)
       end
     end
@@ -152,6 +164,7 @@ def test_generating_components_with_custom_component_parent_class
       run_generator %w[user]
 
       assert_file "app/components/user_component.rb" do |component|
+        assert_no_match(/module/, component)
         assert_match(/class UserComponent < MyBaseComponent/, component)
       end
     end
@@ -163,6 +176,7 @@ def test_generating_components_with_application_component_class_and_custom_paren
         run_generator %w[user]
 
         assert_file "app/components/user_component.rb" do |component|
+          assert_no_match(/module/, component)
           assert_match(/class UserComponent < MyBaseComponent/, component)
         end
       end

test/sandbox/test/generators/preview_generator_test.rb

@@ -18,6 +18,7 @@ def test_component_preview
       run_generator %w[user --preview]
 
       assert_file "test/components/previews/user_component_preview.rb" do |component|
+        assert_no_match(/module/, component)
         assert_match(/class UserComponentPreview < /, component)
         assert_match(/render\(UserComponent.new\)/, component)
       end
@@ -29,6 +30,7 @@ def test_component_preview_with_preview_path_option
       run_generator %w[user --preview --preview-path other/test/components/previews]
 
       assert_file "other/test/components/previews/user_component_preview.rb" do |component|
+        assert_no_match(/module/, component)
         assert_match(/class UserComponentPreview < /, component)
         assert_match(/render\(UserComponent.new\)/, component)
       end
@@ -40,6 +42,7 @@ def test_component_preview_with_one_overridden_preview_path
       run_generator %w[user --preview]
 
       assert_file "spec/components/previews/user_component_preview.rb" do |component|
+        assert_no_match(/module/, component)
         assert_match(/class UserComponentPreview < /, component)
         assert_match(/render\(UserComponent.new\)/, component)
       end
@@ -61,6 +64,7 @@ def test_component_preview_with_two_overridden_preview_paths_and_preview_path_op
       run_generator %w[user --preview --preview-path other/test/components/previews]
 
       assert_file "other/test/components/previews/user_component_preview.rb" do |component|
+        assert_no_match(/module/, component)
         assert_match(/class UserComponentPreview < /, component)
         assert_match(/render\(UserComponent.new\)/, component)
       end
@@ -72,6 +76,7 @@ def test_component_preview_with_namespace
       run_generator %w[admins/user --preview]
 
       assert_file "test/components/previews/admins/user_component_preview.rb" do |component|
+        assert_no_match(/module/, component)
         assert_match(/class Admins::UserComponentPreview < /, component)
         assert_match(/render\(Admins::UserComponent.new\)/, component)
       end
@@ -83,6 +88,7 @@ def test_component_generator_with_attributes
       run_generator %w[user nickname fullname]
 
       assert_file "test/components/previews/user_component_preview.rb" do |preview|
+        assert_no_match(/module/, preview)
         assert_match(/class UserComponentPreview/, preview)
         assert_match(/render\(UserComponent.new\(nickname: "nickname", fullname: "fullname"\)\)/, preview)
       end
@@ -94,6 +100,7 @@ def test_component_with_namespace_and_attributes
       run_generator %w[admins/user nickname fullname]
 
       assert_file "test/components/previews/admins/user_component_preview.rb" do |preview|
+        assert_no_match(/module/, preview)
         assert_match(/class Admins::UserComponentPreview/, preview)
         assert_match(/render\(Admins::UserComponent.new\(nickname: "nickname", fullname: "fullname"\)\)/, preview)
       end

test/sandbox/test/generators/test_unit_generator_test.rb

@@ -14,6 +14,7 @@ def test_generates_component
     run_generator %w[Dummy data]
 
     assert_file "test/components/dummy_component_test.rb" do |content|
+      assert_no_match(/module/, content)
       assert_match(
         /render_inline\(DummyComponent.new\(message: "Hello, components!"\)\).css\("span"\).to_html/, content
       )

test/test_engine/app/components/test_engine/example_component.html.erb

@@ -0,0 +1 @@
+<div>Add Example template here</div>

test/test_engine/app/components/test_engine/example_component.rb

@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+module TestEngine
+  class ExampleComponent < ViewComponent::Base; end
+end

test/test_engine/lib/test_engine.rb

@@ -0,0 +1,6 @@
+require "test_engine/version"
+require "test_engine/engine"
+
+module TestEngine
+  # Your code goes here...
+end

test/test_engine/lib/test_engine/engine.rb

@@ -0,0 +1,5 @@
+module TestEngine
+  class Engine < ::Rails::Engine
+    isolate_namespace TestEngine
+  end
+end

test/test_engine/lib/test_engine/version.rb

@@ -0,0 +1,3 @@
+module TestEngine
+  VERSION = "0.1.0"
+end

test/test_engine/test/components/previews/test_engine/example_component_preview.rb

@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+module TestEngine
+  class ExampleComponentPreview < ViewComponent::Preview
+    def default
+      render(ExampleComponent.new)
+    end
+  end
+end

test/test_engine/test/config_test.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+require_relative "../test_helper"
+
+module ViewComponent
+  class ConfigTest < TestCase
+    def setup
+      @config = ViewComponent::Config.new
+    end
+
+    def test_defaults_are_correct
+      assert_equal @config.generate, {preview_path: ""}
+      assert_equal @config.preview_controller, "ViewComponentsController"
+      assert_equal @config.preview_route, "/rails/view_components"
+      assert_equal @config.show_previews_source, false
+      assert_equal @config.instrumentation_enabled, false
+      assert_equal @config.use_deprecated_instrumentation_name, true
+      assert_equal @config.render_monkey_patch_enabled, true
+      assert_equal @config.show_previews, true
+      assert_equal @config.preview_paths, ["#{TestEngine::Engine.root}/test/components/previews"]
+    end
+  end
+end

test/test_engine/test/generators/component_generator_test.rb

@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+require_relative "../../test_helper"
+require "rails/generators/component/component_generator"
+
+class ComponentGeneratorTest < Rails::Generators::TestCase
+  tests Rails::Generators::ComponentGenerator
+  destination Dir.mktmpdir
+  setup :prepare_destination
+
+  def test_component
+    run_generator %w[example]
+
+    assert_file "app/components/test_engine/example_component.rb" do |component|
+      assert_match(/module TestEngine/, component)
+      assert_match(/class ExampleComponent < ViewComponent::Base/, component)
+      assert_no_match(/def initialize/, component)
+    end
+  end
+end

test/test_engine/test/generators/preview_generator_test.rb

@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+require_relative "../../test_helper"
+require "rails/generators/preview/component_generator"
+
+class PreviewGeneratorTest < Rails::Generators::TestCase
+  tests Preview::Generators::ComponentGenerator
+  destination Dir.mktmpdir
+  setup :prepare_destination
+
+  def test_component_preview
+    with_preview_paths([]) do
+      run_generator %w[example --preview]
+
+      assert_file "test/components/previews/test_engine/example_component_preview.rb" do |component|
+        assert_match(/module TestEngine/, component)
+        assert_match(/class ExampleComponentPreview < /, component)
+        assert_match(/render\(ExampleComponent.new\)/, component)
+      end
+    end
+  end
+end

test/test_engine/test/generators/test_unit_generator_test.rb

@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+require_relative "../../test_helper"
+require "rails/generators/test_unit/component_generator"
+
+class TestUnitGeneratorTest < Rails::Generators::TestCase
+  tests TestUnit::Generators::ComponentGenerator
+  destination Dir.mktmpdir
+  setup :prepare_destination
+
+  def test_component_tests
+    run_generator %w[example --test-framework test_unit]
+
+    assert_file "test/components/test_engine/example_component_test.rb" do |component|
+      assert_no_match(/module/, component)
+      assert_match(/class TestEngine::ExampleComponentTest < /, component)
+      assert_match(/def test_component_renders_something_useful/, component)
+    end
+  end
+end