Add case study specific files

Add case studies model, view, controller, route and tests as well as content_item_model_presenter and related concerns

Commit audit trail:
- https://github.com/alphagov/government-frontend/blob/0aee348d51cebacd5344115f2ca02bdb17095249/app/presenters/case_study_presenter.rb
- https://github.com/alphagov/government-frontend/blob/0aee348d51cebacd5344115f2ca02bdb17095249/app/views/content_items/case_study.html.erb
- https://github.com/alphagov/government-frontend/blob/0aee348d51cebacd5344115f2ca02bdb17095249/test/integration/case_study_test.rb
- https://github.com/alphagov/government-frontend/blob/0aee348d51cebacd5344115f2ca02bdb17095249/test/presenters/case_study_presenter_test.rb
- https://github.com/alphagov/government-frontend/blob/0aee348d51cebacd5344115f2ca02bdb17095249/config/routes.rb

Update app/views/components/_published_dates.html.erb to render dates correctly

app/controllers/case_study_controller.rb

@@ -0,0 +1,5 @@
+class CaseStudyController < ContentItemsController
+  def show
+    @case_study_presenter = ContentItemModelPresenter.new(content_item)
+  end
+end

app/models/case_study.rb

@@ -0,0 +1,8 @@
+class CaseStudy < ContentItem
+  include Updatable
+  include WorldwideOrganisations
+
+  def related_entities
+    (linkable_organisations + worldwide_organisations).uniq
+  end
+end

app/views/case_study/show.html.erb

@@ -0,0 +1,71 @@
+<% content_for :title, "#{@case_study_presenter.page_title} - #{I18n.t("formats.#{content_item.document_type}", count: 1)} - GOV.UK" %>
+
+<% content_for :extra_headers do %>
+  <%= render "govuk_publishing_components/components/machine_readable_metadata", { content_item: content_item.to_h, schema: :article } %>
+<% end %>
+
+<main role="main" id="content" class="case-study" <%= lang_attribute(content_item.locale) %>>
+  <div class="govuk-grid-row">
+    <div class="govuk-grid-column-two-thirds responsive-top-margin">
+      <%= render 'govuk_publishing_components/components/title', {
+        title: content_item.title,
+        context: I18n.t("formats.#{content_item.document_type}", count: 1),
+        context_locale: t_locale_fallback("formats.#{content_item.document_type}", count: 1),
+        average_title_length: "long",
+      } %>
+    </div>
+    <%= render 'shared/translations' %>
+    <div class="govuk-grid-column-two-thirds">
+      <%= render 'govuk_publishing_components/components/lead_paragraph', text: content_item.description %>
+    </div>
+  </div>
+
+  <%= render 'shared/publisher_metadata', locals: {
+    from: govuk_styled_links_list(content_item.related_entities),
+    first_published: display_date(content_item.first_public_at || content_item.first_published_at),
+    last_updated: display_date(content_item.updated),
+    see_updates_link: true,
+    }
+  %>
+
+  <% if content_item.withdrawn? %>
+    <% withdrawn_time_tag = tag.time(display_date(content_item.withdrawn_at), datetime: content_item.withdrawn_at) %>
+
+    <%= render 'govuk_publishing_components/components/notice', {
+      title: I18n.t("formats.case_study.withdrawn_notice.title", schema_name: I18n.t("formats.#{content_item.schema_name}", count: 1, locale: :en).downcase, withdrawn_time: withdrawn_time_tag).html_safe,
+      description_govspeak: content_item.withdrawn_explanation&.html_safe,
+      time: withdrawn_time_tag,
+      lang: "en",
+    }  %>
+  <% end %>
+
+  <div class="govuk-grid-row">
+    <div class="govuk-grid-column-two-thirds">
+      <div class="content-bottom-margin">
+        <div class="responsive-bottom-margin">
+          <%= render 'components/figure',
+            src: content_item.image["url"],
+            alt: content_item.image["alt_text"],
+            credit: content_item.image["credit"],
+            caption: content_item.image["caption"] if content_item.image %>
+
+          <%= render 'govuk_publishing_components/components/govspeak', {
+            direction: page_text_direction,
+          } do %>
+            <%= raw(content_item.body) %>
+          <% end %>
+        </div>
+
+        <%= render 'components/published_dates', {
+          published: display_date(content_item.first_public_at),
+          last_updated: display_date(content_item.updated),
+          history: content_item.history
+        } %>
+      </div>
+    </div>
+
+    <%= render 'shared/sidebar_navigation' %>
+  </div>
+</main>
+
+<%= render 'shared/footer_navigation' %>

config/routes.rb

@@ -77,6 +77,8 @@
     # Placeholder for attachments being virus-scanned
     get "/placeholder", to: "placeholder#show"
 
+    get "/case-studies/:slug(.:locale)", to: "case_study#show", as: :case_study
+
     scope "/get-involved" do
       get "/", to: "get_involved#show"
       get "/take-part/:slug", to: "take_part#show"

spec/models/case_study_spec.rb

@@ -0,0 +1,4 @@
+RSpec.describe CaseStudy do
+  it_behaves_like "it can be updated", "case_study"
+  it_behaves_like "it can have worldwide organisations", "case_study"
+end

spec/requests/case_study_spec.rb

@@ -0,0 +1,13 @@
+RSpec.describe "Case Study" do
+  before do
+    content_store_has_example_item("/government/case-studies/get-britain-building-carlisle-park", schema: :case_study)
+  end
+
+  context "when visiting the index route" do
+    it "returns 200" do
+      get "/government/case-studies/get-britain-building-carlisle-park"
+
+      expect(response).to have_http_status(:ok)
+    end
+  end
+end

spec/system/case_study_spec.rb

@@ -0,0 +1,41 @@
+RSpec.describe "CaseStudy" do
+  before do
+    content_store_has_example_item("/government/case-studies/get-britain-building-carlisle-park", schema: :case_study)
+    content_store_has_example_item("/government/case-studies/doing-business-in-spain", schema: :case_study, example: "doing-business-in-spain")
+  end
+
+  it_behaves_like "it has meta tags", "case_study", "/government/case-studies/doing-business-in-spain"
+  it_behaves_like "it has meta tags for images", "case_study", "/government/case-studies/doing-business-in-spain"
+
+  context "when visiting a Case Study page" do
+    it "displays the case_study page" do
+      visit "/government/case-studies/get-britain-building-carlisle-park"
+
+      expect(page).to have_title("Get Britain Building: Carlisle Park - Case study - GOV.UK")
+
+      expect(page).to have_css("h1", text: "Get Britain Building: Carlisle Park")
+      expect(page).to have_text("Nearly 400 homes are set to be built on the site of a former tar distillery thanks to Gleeson Homes and HCA investment.")
+
+      expect(page).to have_css(".gem-c-translation-nav")
+    end
+
+    context "when visiting a Withdrawn Case Study page which is also translatable" do
+      it "displays the case_study page" do
+        visit "/government/case-studies/doing-business-in-spain"
+
+        expect(page).to have_title("[Withdrawn] Doing business in Spain - Case study - GOV.UK")
+
+        expect(page).to have_css("h1", text: "Doing business in Spain")
+        expect(page).to have_text("This case study was withdrawn on")
+
+        expect(page).to have_css(".gem-c-translation-nav")
+      end
+    end
+
+    it "does not display a single page notification button" do
+      visit "/government/case-studies/get-britain-building-carlisle-park"
+
+      expect(page).not_to have_css(".gem-c-single-page-notification-button")
+    end
+  end
+end