Component specific branding

app/components/govuk_component/base.rb

@@ -27,6 +27,13 @@ def initialize(classes:, html_attributes:)
   end
 
   def brand(override = nil)
-    override || config.brand
+    override || config.brand_overrides.fetch(class_prefix, config.brand)
+  end
+
+  # We want the main component and the subcomponents here so
+  # match on the second segment of the component class name
+  def class_prefix
+    # FIXME: this looks a bit dodgy...
+    self.class.name.match(/\w+::\w+/).to_s
   end
 end

lib/govuk/components/engine.rb

@@ -33,6 +33,7 @@ def reset!
     # Default components configuration
     #
     # +:brand+ sets the value used to prefix all classes, used to allow the components to be branded for alternative (similar) design systems
+    # +:brand_overrides+ sets the value used to prefix classes and slots for the component class.
     # +:default_back_link_text+ Default text for the back link, defaults to +Back+
     # +:default_breadcrumbs_collapse_on_mobile+ false
     # +:default_breadcrumbs_hide_in_print+ false
@@ -75,6 +76,30 @@ def reset!
     # +:enable_auto_table_scopes+ automatically adds a scope of 'col' to th elements in thead and 'row' to th elements in tbody.
     DEFAULTS = {
       brand: 'govuk',
+      brand_overrides: {
+        # 'GovukComponent::AccordionComponent'           => 'another-brand',
+        # 'GovukComponent::BackLinkComponent'            => 'another-brand',
+        # 'GovukComponent::BreadcrumbsComponent'         => 'another-brand',
+        # 'GovukComponent::CookieBannerComponent'        => 'another-brand',
+        # 'GovukComponent::DetailsComponent'             => 'another-brand',
+        # 'GovukComponent::ExitThisPageComponent'        => 'another-brand',
+        # 'GovukComponent::FooterComponent'              => 'another-brand',
+        # 'GovukComponent::HeaderComponent'              => 'another-brand',
+        # 'GovukComponent::InsetTextComponent'           => 'another-brand',
+        # 'GovukComponent::NotificationBannerComponent'  => 'another-brand',
+        # 'GovukComponent::PaginationComponent'          => 'another-brand',
+        # 'GovukComponent::PanelComponent'               => 'another-brand',
+        # 'GovukComponent::PhaseBannerComponent'         => 'another-brand',
+        # 'GovukComponent::SectionBreakComponent'        => 'another-brand',
+        # 'GovukComponent::ServiceNavigationComponent'   => 'another-brand',
+        # 'GovukComponent::StartButtonComponent'         => 'another-brand',
+        # 'GovukComponent::SummaryListComponent'         => 'another-brand',
+        # 'GovukComponent::TableComponent'               => 'another-brand',
+        # 'GovukComponent::TabComponent'                 => 'another-brand',
+        # 'GovukComponent::TagComponent'                 => 'another-brand',
+        # 'GovukComponent::TaskListComponent'            => 'another-brand',
+        # 'GovukComponent::WarningTextComponent'         => 'another-brand',
+      },
       default_back_link_text: 'Back',
       default_breadcrumbs_collapse_on_mobile: false,
       default_breadcrumbs_hide_in_print: false,

spec/components/govuk_component/accordion_component_spec.rb

@@ -194,6 +194,7 @@
   it_behaves_like 'a component that accepts custom classes'
   it_behaves_like 'a component that accepts custom HTML attributes'
   it_behaves_like 'a component that supports custom branding'
+  it_behaves_like 'a component that supports brand overrides'
 
   context 'slot arguments' do
     let(:slot) { :section }

spec/components/govuk_component/back_link_component_spec.rb

@@ -49,4 +49,5 @@
   it_behaves_like 'a component that accepts custom classes'
   it_behaves_like 'a component that accepts custom HTML attributes'
   it_behaves_like 'a component that supports custom branding'
+  it_behaves_like 'a component that supports brand overrides'
 end

spec/components/govuk_component/breadcrumbs_component_spec.rb

@@ -89,4 +89,5 @@
   it_behaves_like 'a component that accepts custom classes'
   it_behaves_like 'a component that accepts custom HTML attributes'
   it_behaves_like 'a component that supports custom branding'
+  it_behaves_like 'a component that supports brand overrides'
 end

spec/components/govuk_component/cookie_banner_component_spec.rb

@@ -106,6 +106,9 @@
   it_behaves_like 'a component that accepts custom classes'
   it_behaves_like 'a component that accepts custom HTML attributes'
   it_behaves_like 'a component that supports custom branding'
+  it_behaves_like 'a component that supports brand overrides' do
+    let(:component_class_name) { "GovukComponent::CookieBannerComponent" }
+  end
 
   context "when there is no text or block" do
     specify "raises an appropriate error" do

spec/components/govuk_component/details_component_spec.rb

@@ -9,6 +9,7 @@
   it_behaves_like 'a component that accepts custom classes'
   it_behaves_like 'a component that accepts custom HTML attributes'
   it_behaves_like 'a component that supports custom branding'
+  it_behaves_like 'a component that supports brand overrides'
 
   context 'when text is supplied' do
     before { render_inline(described_class.new(**kwargs)) }

spec/components/govuk_component/exit_this_page_component_spec.rb

@@ -114,4 +114,5 @@
   end
 
   it_behaves_like 'a component that supports custom branding'
+  it_behaves_like 'a component that supports brand overrides'
 end

spec/components/govuk_component/footer_component_spec.rb

@@ -282,6 +282,7 @@
   it_behaves_like 'a component that accepts custom classes'
   it_behaves_like 'a component that accepts custom HTML attributes'
   it_behaves_like 'a component that supports custom branding'
+  it_behaves_like 'a component that supports brand overrides'
 
   describe "navigation" do
     let(:custom_text) { "Some meta html" }

spec/components/govuk_component/header_component_spec.rb

@@ -319,6 +319,7 @@
   it_behaves_like 'a component that accepts custom classes'
   it_behaves_like 'a component that accepts custom HTML attributes'
   it_behaves_like 'a component that supports custom branding'
+  it_behaves_like 'a component that supports brand overrides'
 
   context 'slot arguments' do
     let(:slot) { :navigation_item }

spec/components/govuk_component/inset_text_component_spec.rb

@@ -9,6 +9,7 @@
   it_behaves_like 'a component that accepts custom classes'
   it_behaves_like 'a component that accepts custom HTML attributes'
   it_behaves_like 'a component that supports custom branding'
+  it_behaves_like 'a component that supports brand overrides'
 
   context 'when text is supplied' do
     before { render_inline(described_class.new(**kwargs)) }

spec/components/govuk_component/notification_banner_component_spec.rb

@@ -18,6 +18,7 @@
       let(:kwargs) { { title_text: title, text: "something", title_id: 'custom-id' } }
 
       it_behaves_like 'a component that supports custom branding'
+      it_behaves_like 'a component that supports brand overrides'
     end
 
     context "when supplied with a block" do

spec/components/govuk_component/pagination_component_spec.rb

@@ -16,6 +16,7 @@
   it_behaves_like 'a component that accepts custom classes'
   it_behaves_like 'a component that accepts custom HTML attributes'
   it_behaves_like 'a component that supports custom branding'
+  it_behaves_like 'a component that supports brand overrides'
 
   specify "renders some page items" do
     expect(rendered_content).to have_tag("nav", with: { class: component_css_class }) do

spec/components/govuk_component/panel_component_spec.rb

@@ -10,6 +10,7 @@
   it_behaves_like 'a component that accepts custom classes'
   it_behaves_like 'a component that accepts custom HTML attributes'
   it_behaves_like 'a component that supports custom branding'
+  it_behaves_like 'a component that supports brand overrides'
 
   specify 'contains a panel with the correct title and text' do
     render_inline(described_class.new(**kwargs))

spec/components/govuk_component/phase_banner_component_spec.rb

@@ -46,4 +46,7 @@
   it_behaves_like 'a component that accepts custom classes'
   it_behaves_like 'a component that accepts custom HTML attributes'
   it_behaves_like 'a component that supports custom branding'
+  it_behaves_like 'a component that supports brand overrides' do
+    let(:extra_overrides) { ["GovukComponent::TagComponent"] }
+  end
 end

spec/components/govuk_component/section_break_component_spec.rb

@@ -7,6 +7,7 @@
   it_behaves_like "a component that accepts custom classes"
   it_behaves_like "a component that accepts custom HTML attributes"
   it_behaves_like 'a component that supports custom branding'
+  it_behaves_like 'a component that supports brand overrides'
 
   context "when visible is true" do
     it "renders the section break with the visible class" do

spec/components/govuk_component/service_navigation_component_spec.rb

@@ -15,6 +15,7 @@
   it_behaves_like 'a component that accepts custom classes'
   it_behaves_like 'a component that accepts custom HTML attributes'
   it_behaves_like 'a component that supports custom branding'
+  it_behaves_like 'a component that supports brand overrides'
 
   specify 'renders a div with the expected attributes' do
     expect(rendered_content).to have_tag("div", with: { class: component_css_class, 'data-module' => 'govuk-service-navigation' })

spec/components/govuk_component/start_button_component_spec.rb

@@ -67,5 +67,6 @@
     it_behaves_like 'a component that accepts custom classes'
     it_behaves_like 'a component that accepts custom HTML attributes'
     it_behaves_like 'a component that supports custom branding'
+    it_behaves_like 'a component that supports brand overrides'
   end
 end

spec/components/govuk_component/summary_list_component_spec.rb

@@ -11,6 +11,7 @@
   it_behaves_like 'a component that accepts custom classes'
   it_behaves_like 'a component that accepts custom HTML attributes'
   it_behaves_like 'a component that supports custom branding'
+  it_behaves_like 'a component that supports brand overrides'
 
   subject! do
     render_inline(described_class.new(**kwargs)) do |component|

spec/components/govuk_component/tab_component_spec.rb

@@ -125,6 +125,7 @@
   it_behaves_like 'a component that accepts custom classes'
   it_behaves_like 'a component that accepts custom HTML attributes'
   it_behaves_like 'a component that supports custom branding'
+  it_behaves_like 'a component that supports brand overrides'
 
   context 'slot arguments' do
     let(:slot) { :tab }

spec/components/govuk_component/table_component_spec.rb

@@ -498,6 +498,7 @@
   it_behaves_like 'a component that accepts custom classes'
   it_behaves_like 'a component that accepts custom HTML attributes'
   it_behaves_like 'a component that supports custom branding'
+  it_behaves_like 'a component that supports brand overrides'
 
   describe "column groups and columns" do
     subject! do

spec/components/govuk_component/tag_component_spec.rb

@@ -70,4 +70,7 @@
   it_behaves_like 'a component that accepts custom classes'
   it_behaves_like 'a component that accepts custom HTML attributes'
   it_behaves_like 'a component that supports custom branding'
+  it_behaves_like 'a component that supports brand overrides' do
+    let(:component_class) { "GovukComponent::TagComponent" }
+  end
 end

spec/components/govuk_component/task_list_component_spec.rb

@@ -372,4 +372,5 @@
   it_behaves_like 'a component that accepts custom classes'
   it_behaves_like 'a component that accepts custom HTML attributes'
   it_behaves_like 'a component that supports custom branding'
+  it_behaves_like 'a component that supports brand overrides'
 end

spec/components/govuk_component/warning_text_component_spec.rb

@@ -74,4 +74,5 @@
   it_behaves_like 'a component that accepts custom classes'
   it_behaves_like 'a component that accepts custom HTML attributes'
   it_behaves_like 'a component that supports custom branding'
+  it_behaves_like 'a component that supports brand overrides'
 end

spec/components/shared/a_component_that_supports_custom_branding.rb

@@ -24,3 +24,33 @@
     expect(rendered_content).not_to match(Regexp.new(default_brand))
   end
 end
+
+shared_examples 'a component that supports brand overrides' do
+  let(:default_brand) { 'govuk' }
+  let(:custom_brand) { 'carrington-institute' }
+
+  before do
+    class_name = defined?(component_class_name) ? component_class_name : described_class.name
+    extra_classes = defined?(extra_overrides) ? extra_overrides.index_with(custom_brand) : {}
+
+    Govuk::Components.configure do |conf|
+      conf.brand_overrides = { class_name => custom_brand, **extra_classes }
+    end
+  end
+
+  after do
+    Govuk::Components.reset!
+  end
+
+  specify "should contain the custom branding" do
+    render_inline(described_class.new(**kwargs))
+
+    expect(rendered_content).to match(Regexp.new(custom_brand))
+  end
+
+  specify "should not contain any default branding" do
+    render_inline(described_class.new(**kwargs))
+
+    expect(rendered_content).not_to match(Regexp.new(default_brand))
+  end
+end