Extract some validations to the model

app/controllers/merge_requests_controller.rb

@@ -123,7 +123,7 @@ private
       end
     end
 
-    if merge_params[:telephone_number_correct] == "1"
+    if merge_params[:telephone_number_correct] == "true"
       merge_params[:new_telephone_number] = nil
     end
 
@@ -143,12 +143,9 @@ private
         else
           @merge_request.errors.add(:telephone_number_correct, :invalid)
         end
-      elsif merge_request_params[:telephone_number_correct] == "0" && merge_request_params[:new_telephone_number].blank?
-        @merge_request.errors.add(:new_telephone_number, :blank)
       end
     when "new_organisation_name"
       @merge_request.errors.add(:new_organisation_name, :blank) if merge_request_params[:new_organisation_name].blank?
-      @merge_request.errors.add(:new_organisation_name, :invalid) if Organisation.where("lower(name) = ?", merge_request_params[:new_organisation_name]&.downcase).exists?
     end
   end
 

app/models/merge_request.rb

@@ -3,10 +3,18 @@ class MergeRequest < ApplicationRecord
   has_many :merge_request_organisations
   belongs_to :absorbing_organisation, class_name: "Organisation", optional: true
   has_many :merging_organisations, through: :merge_request_organisations, source: :merging_organisation
+  validate :organisation_name_uniqueness, if: :new_organisation_name
+  validates :new_telephone_number, presence: true, if: -> { telephone_number_correct == false }
 
   STATUS = {
     "unsubmitted" => 0,
     "submitted" => 1,
   }.freeze
   enum status: STATUS
+
+  def organisation_name_uniqueness
+    if Organisation.where("lower(name) = ?", new_organisation_name&.downcase).exists?
+      errors.add(:new_organisation_name, :invalid)
+    end
+  end
 end

app/views/merge_requests/confirm_telephone_number.html.erb

@@ -20,8 +20,8 @@
 
       <% if @merge_request.absorbing_organisation.phone.present? %>
         <%= f.govuk_radio_buttons_fieldset(:telephone_number_correct, legend: nil) do %>
-          <%= f.govuk_radio_button :telephone_number_correct, 1, checked: @merge_request.telephone_number_correct?, label: { text: "This telephone number is correct" }, link_errors: true %>
-          <%= f.govuk_radio_button :telephone_number_correct, 0, checked: @merge_request.new_telephone_number.present?, label: { text: "Enter a new phone number" } do %>
+          <%= f.govuk_radio_button :telephone_number_correct, true, checked: @merge_request.telephone_number_correct?, label: { text: "This telephone number is correct" }, link_errors: true %>
+          <%= f.govuk_radio_button :telephone_number_correct, false, checked: @merge_request.new_telephone_number.present?, label: { text: "Enter a new phone number" } do %>
             <%= f.govuk_text_field :new_telephone_number, label: { text: "Telephone number" }, width: "two-thirds" %>
           <% end %>
           <%= f.hidden_field :page, value: "confirm_telephone_number" %>

spec/requests/merge_requests_controller_spec.rb

@@ -367,7 +367,7 @@ RSpec.describe MergeRequestsController, type: :request do
         context "when confirming the number" do
           let(:merge_request) { MergeRequest.create!(requesting_organisation: organisation, new_absorbing_organisation: true, new_telephone_number: "123") }
           let(:params) do
-            { merge_request: { telephone_number_correct: "1", page: "confirm_telephone_number" } }
+            { merge_request: { telephone_number_correct: true, page: "confirm_telephone_number" } }
           end
 
           let(:request) do
@@ -392,7 +392,7 @@ RSpec.describe MergeRequestsController, type: :request do
         context "when setting new number" do
           let(:merge_request) { MergeRequest.create!(requesting_organisation: organisation, new_absorbing_organisation: true) }
           let(:params) do
-            { merge_request: { telephone_number_correct: "0", new_telephone_number: "123", page: "confirm_telephone_number" } }
+            { merge_request: { telephone_number_correct: false, new_telephone_number: "123", page: "confirm_telephone_number" } }
           end
 
           let(:request) do
@@ -455,7 +455,7 @@ RSpec.describe MergeRequestsController, type: :request do
         context "when not answering the phone number" do
           let(:merge_request) { MergeRequest.create!(requesting_organisation: organisation, absorbing_organisation: other_organisation) }
           let(:params) do
-            { merge_request: { page: "confirm_telephone_number", telephone_number_correct: "0" } }
+            { merge_request: { page: "confirm_telephone_number", telephone_number_correct: false } }
           end
           let(:request) do
             patch "/merge-request/#{merge_request.id}", headers:, params: