Allow users to hide the user research recruitment banner

Trello: https://trello.com/c/yGMU3sR2

We set a session cookie to hide the banner until the user restarts their
browser.

app/controllers/root_controller.rb

@@ -14,4 +14,11 @@ def index
   def signin_required
     @application = ::Doorkeeper::Application.find_by(id: session.delete(:signin_missing_for_application))
   end
+
+private
+
+  def show_user_research_recruitment_banner?
+    !cookies[:dismiss_user_research_recruitment_banner]
+  end
+  helper_method :show_user_research_recruitment_banner?
 end

app/controllers/user_research_recruitment_controller.rb

@@ -0,0 +1,11 @@
+class UserResearchRecruitmentController < ApplicationController
+  before_action :authenticate_user!
+  skip_after_action :verify_authorized
+
+  def update
+    if params[:choice] == "dismiss-banner"
+      cookies[:dismiss_user_research_recruitment_banner] = true
+      redirect_to root_path
+    end
+  end
+end

app/views/root/index.html.erb

@@ -1,27 +1,29 @@
 <% content_for :title, "Your applications" %>
 
+<% if show_user_research_recruitment_banner? %>
   <% content_for :user_research_recruitment_banner do %>
     <section class="user-research-recruitment-banner">
       <div class="govuk-width-container">
         <hr class="user-research-recruitment-banner__divider govuk-section-break govuk-section-break--l govuk-!-margin-top-0">
         <h1 class="user-research-recruitment-banner__title govuk-heading-xl">Help us improve GOV.UK Publishing</h1>
         <p class="user-research-recruitment-banner__intro govuk-body">We're holding research sessions to make Publishing work better.</p>
-        <%= form_tag "#" do %>
+        <%= form_tag user_research_recruitment_update_path, method: :put do %>
           <div class="user-research-recruitment-banner__buttons govuk-button-group">
             <button class="govuk-!-font-size-24 govuk-!-font-weight-bold govuk-button govuk-button--start govuk-button--inverse" type="submit">
               <span>Find out more</span>
               <svg class="govuk-button__start-icon govuk-!-display-none-print" xmlns="http://www.w3.org/2000/svg" width="17.5" height="19" viewBox="0 0 33 40" focusable="false" aria-hidden="true">
                 <path fill="currentColor" d="M0 0h13l20 20-20 20H0l20-20z"></path>
               </svg>
             </button>
-            <button class="govuk-button govuk-button--inverse" type="submit">
+            <button class="govuk-button govuk-button--inverse" type="submit" name="choice" value="dismiss-banner">
               Hide this
             </button>
           </div>
         <% end %>
       </div>
     </section>
   <% end %>
+<% end %>
 
 <div class="govuk-grid-row">
   <div class="govuk-grid-column-two-thirds">

config/routes.rb

@@ -77,4 +77,6 @@
   get "/signin-required" => "root#signin_required"
 
   root to: "root#index"
+
+  put "/user-research-recruitment/update" => "user_research_recruitment#update"
 end

test/controllers/user_research_recruitment_controller_test.rb

@@ -0,0 +1,35 @@
+require "test_helper"
+
+class UserResearchRecruitmentControllerTest < ActionController::TestCase
+  attr_reader :choice
+
+  context "#update" do
+    context "when user clicks the button to dismiss the banner" do
+      setup do
+        @choice = "dismiss-banner"
+      end
+
+      should "require signed in users" do
+        put :update, params: { choice: }
+
+        assert_redirected_to new_user_session_path
+      end
+
+      should "set session cookie" do
+        sign_in create(:user)
+
+        put :update, params: { choice: }
+
+        assert cookies[:dismiss_user_research_recruitment_banner]
+      end
+
+      should "redirect to root path" do
+        sign_in create(:user)
+
+        put :update, params: { choice: }
+
+        assert_redirected_to root_path
+      end
+    end
+  end
+end

test/integration/user_research_recruitment_banner_test.rb

@@ -26,6 +26,32 @@ class UserResearchRecruitmentBannerTest < ActionDispatch::IntegrationTest
     assert_not has_content?(user_research_recruitment_banner_title)
   end
 
+  should "hide the banner until the next session" do
+    user = create(:user, name: "user-name", email: "user@example.com")
+
+    using_session("Session 1") do
+      visit new_user_session_path
+      signin_with(user)
+
+      assert has_content?(user_research_recruitment_banner_title)
+
+      within ".user-research-recruitment-banner" do
+        click_on "Hide this"
+      end
+
+      visit root_path
+
+      assert_not has_content?(user_research_recruitment_banner_title)
+    end
+
+    using_session("Session 2") do
+      visit new_user_session_path
+      signin_with(user)
+
+      assert has_content?(user_research_recruitment_banner_title)
+    end
+  end
+
 private
 
   def user_research_recruitment_banner_title