validate all the required scheme questions are answered

app/controllers/schemes_controller.rb

@@ -128,6 +128,8 @@ private
       "schemes/details"
     elsif page.include?("edit")
       "schemes/edit_name"
+    elsif page.include?("check-answers")
+      "schemes/check_answers"
     end
   end
 

app/models/scheme.rb

@@ -9,6 +9,8 @@ class Scheme < ApplicationRecord
   scope :search_by_postcode, ->(postcode) { joins(:locations).where("locations.postcode ILIKE ?", "%#{postcode.delete(' ')}%") }
   scope :search_by, ->(param) { search_by_postcode(param).or(search_by_service_name(param)).or(filter_by_id(param)).distinct }
 
+  validate :validate_confirmed
+
   SENSITIVE = {
     No: 0,
     Yes: 1,
@@ -205,4 +207,12 @@ class Scheme < ApplicationRecord
   def arrangement_type_same?
     arrangement_type.present? && ARRANGEMENT_TYPE[arrangement_type.to_sym] == "D"
   end
+
+  def validate_confirmed
+    required_attributes = attribute_names - %w[id created_at updated_at old_id old_visible_id confirmed end_date sensitive secondary_client_group total_units has_other_client_group]
+
+    if confirmed == true && required_attributes.any? { |attribute| self[attribute].blank? }
+      errors.add :base, "Please answer all the required questions"
+    end
+  end
 end

app/views/schemes/check_answers.html.erb

@@ -1,6 +1,8 @@
 <% content_for :title, "Check your answers before creating this scheme" %>
 <%= render partial: "organisations/headings", locals: { main: "Check your changes before creating this scheme", sub: @scheme.service_name } %>
 
+<%= form_for(@scheme, as: :scheme, method: :patch) do |f| %>
+  <%= f.govuk_error_summary %>
   <div class="govuk-grid-row">
     <div class="govuk-grid-column-three-quarters-from-desktop">
       <%= govuk_tabs(title: "Check your answers before creating this scheme") do |component| %>
@@ -130,8 +132,6 @@
       <% end %>
     </div>
   </div>
-
-<%= form_for(@scheme, as: :scheme, method: :patch) do |f| %>
   <%= f.hidden_field :page, value: "check-answers" %>
   <%= f.hidden_field :confirmed, value: "true" %>
   <% button_label = @scheme.confirmed? ? "Save" : "Create scheme" %>

spec/factories/scheme.rb

@@ -10,6 +10,7 @@ FactoryBot.define do
     primary_client_group { %w[O H M L A G F B D E I S N R Q P X].sample }
     secondary_client_group { %w[O H M L A G F B D E I S N R Q P X].sample }
     owning_organisation { FactoryBot.create(:organisation) }
+    managing_organisation { FactoryBot.create(:organisation) }
     confirmed { true }
     created_at { Time.zone.now }
     trait :export do