Add case studies model, controller, presenter, route and tests

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

app/controllers/case_studies_controller.rb

@@ -0,0 +1,11 @@
+class CaseStudiesController < ContentItemsController
+  def show
+    @case_study = CaseStudiesPresenter.new(@content_item, view_context)
+  end
+
+private
+
+  def content_item_slug
+    request.path
+  end
+end

app/models/case_study.rb

@@ -0,0 +1,5 @@
+class CaseStudy < ContentItem
+  include Metadata
+  include Linkable
+  include Updatable
+end

app/presenters/case_studies_presenter.rb

@@ -0,0 +1,18 @@
+class CaseStudiesPresenter < ContentItemPresenter
+  attr_reader :content_item, :view_context
+
+  def initialize(content_item, view_context)
+    super(content_item)
+    @content_item = content_item
+    @view_context = view_context
+  end
+
+  def title_and_context
+    {
+      title: content_item.title,
+      context: I18n.t("content_item.schema_name.#{content_item.document_type}", count: 1),
+      context_locale: view_context.t_locale_fallback("content_item.schema_name.#{content_item.document_type}", count: 1),
+      average_title_length: "long",
+    }
+  end
+end

app/views/case_studies/show.html.erb

@@ -0,0 +1,52 @@
+<% content_for :title, "#{@content_item.page_title} - #{I18n.t("content_item.schema_name.#{@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 %>
+
+<div class="govuk-grid-row">
+  <div class="govuk-grid-column-two-thirds responsive-top-margin">
+    <%= render 'govuk_publishing_components/components/title', @case_study.title_and_context %>
+  </div>
+  <%= render 'shared/translations' %>
+  <div class="govuk-grid-column-two-thirds">
+    <%= render 'govuk_publishing_components/components/lead_paragraph', text: @content_item.description %>
+  </div>
+</div>
+
+<hr class="govuk-section-break govuk-section-break--s govuk-section-break--visible" aria-hidden="true">
+
+<%= render 'shared/publisher_metadata_with_logo' %>
+<% if @content_item.withdrawn? %>
+  <%= render 'govuk_publishing_components/components/notice', @content_item.withdrawal_notice_component  %>
+<% 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_published_at),
+        last_updated: display_date(@content_item.updated),
+        history: @content_item.history
+      } %>
+    </div>
+  </div>
+
+  <%= render 'shared/sidebar_navigation' %>
+</div>
+
+<%= render 'shared/footer_navigation' %>

config/routes.rb

@@ -74,6 +74,8 @@
     # Placeholder for attachments being virus-scanned
     get "/placeholder", to: "placeholder#show"
 
+    get "/case-studies/:slug(.:locale)", to: "case_studies#show"
+
     scope "/get-involved" do
       get "/take-part/:slug", to: "take_part#show"
     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 "GET index" 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_studies_spec.rb

@@ -0,0 +1,38 @@
+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
+
+  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