feat: make tests pass, simplify code and incorporate tasklist/check answers back routing

app/controllers/form_controller.rb

@@ -124,9 +124,9 @@ private
     if is_referrer_check_answers?
       page_ids = form.subsection_for_page(@page).pages.map(&:id)
       page_index = page_ids.index(@page.id)
-      next_page_id = form.next_page(@page, @log, current_user)
+      next_page_id = form.next_page_id(@page, @log, current_user)
       next_page = form.get_page(next_page_id)
-      previous_page = form.previous_page(@page, @log, current_user)
+      previous_page = form.previous_page_id(@page, @log, current_user)
 
       if next_page&.interruption_screen? || next_page_id == previous_page
         return send("#{@log.class.name.underscore}_#{next_page_id}_path", @log, { referrer: "check_answers" })

app/helpers/tasklist_helper.rb

@@ -15,7 +15,7 @@ module TasklistHelper
     if subsection.pages.first.routed_to?(log, current_user)
       subsection.pages.first.id
     else
-      log.form.next_page(subsection.pages.first, log, current_user)
+      log.form.next_page_id(subsection.pages.first, log, current_user)
     end
   end
 

app/models/form.rb

@@ -61,55 +61,54 @@ class Form
     subsections.find { |s| s.pages.find { |p| p.id == page.id } }
   end
 
-  def next_page(page, log, current_user)
+  def next_page_id(page, log, current_user)
     return page.next_unresolved_page_id || :check_answers if log.unresolved
 
     page_ids = subsection_for_page(page).pages.map(&:id)
     page_index = page_ids.index(page.id)
     page_id = if page.interruption_screen? && log[page.questions[0].id] == 1 && page.routed_to?(log, current_user)
-                previous_page(page, log, current_user)
+                previous_page_id(page, log, current_user)
               else
                 page_ids[page_index + 1]
               end
-    nxt_page = get_page(page_id)
+    next_page = get_page(page_id)
 
-    return :check_answers if nxt_page.nil?
-    return nxt_page.id if nxt_page.routed_to?(log, current_user)
+    return :check_answers if next_page.nil?
+    return next_page.id if next_page.routed_to?(log, current_user)
 
-    next_page(nxt_page, log, current_user)
+    next_page_id(next_page, log, current_user)
   end
 
   def next_page_redirect_path(page, log, current_user)
-    nxt_page = next_page(page, log, current_user)
-    if nxt_page == :check_answers
+    next_page_id = next_page_id(page, log, current_user)
+    if next_page_id == :check_answers
       "#{type}_log_#{subsection_for_page(page).id}_check_answers_path"
     else
-      "#{type}_log_#{nxt_page}_path"
+      "#{type}_log_#{next_page_id}_path"
     end
   end
 
-  def previous_page(page, log, current_user)
+  def previous_page_id(page, log, current_user)
     page_ids = subsection_for_page(page).pages.map(&:id)
     page_index = page_ids.index(page.id)
-    page_id = if page_index.zero?
-                :check_answers
-              else
-                page_ids[page_index - 1]
-              end
-    prvs_page = get_page(page_id)
+    return :tasklist if page_index.zero?
+
+    page_id = page_ids[page_index - 1]
+    previous_page = get_page(page_id)
 
-    return :check_answers if prvs_page.nil?
-    return prvs_page.id if prvs_page.routed_to?(log, current_user)
+    return previous_page.id if previous_page.routed_to?(log, current_user)
 
-    previous_page(prvs_page, log, current_user)
+    previous_page_id(previous_page, log, current_user)
   end
 
-  def previous_page_redirect_path(page, log, current_user)
-    previous_page = previous_page(page, log, current_user)
-    if previous_page == :check_answers
+  def previous_page_redirect_path(page, log, current_user, referrer)
+    previous_page_id = previous_page_id(page, log, current_user)
+    if referrer == "check_answers"
       "#{type}_log_#{subsection_for_page(page).id}_check_answers_path"
+    elsif previous_page_id == :tasklist
+      "#{type}_log_path"
     else
-      "#{type}_log_#{previous_page}_path"
+      "#{type}_log_#{previous_page_id}_path"
     end
   end
 

app/views/form/page.html.erb

@@ -1,11 +1,7 @@
 <% content_for :title, @page.header.presence || @page.questions.first.header.html_safe %>
 
 <% content_for :before_content do %>
-  <% if url_for(:back).include?("check_answers") %>
-    <%= govuk_back_link(href: :back) %>
-  <% else %>
-    <%= govuk_back_link(href: send(@log.form.previous_page_redirect_path(@page, @log, current_user), @log)) %>
-  <% end %>
+  <%= govuk_back_link(href: send(@log.form.previous_page_redirect_path(@page, @log, current_user, params[:referrer]), @log)) %>
 <% end %>
 
 <div data-controller="govukfrontend"></div>

spec/models/form_spec.rb

@@ -17,11 +17,11 @@ RSpec.describe Form, type: :model do
   let(:conditional_section_complete_lettings_log) { FactoryBot.build(:lettings_log, :conditional_section_complete) }
 
   describe ".next_page" do
-    let(:previous_page) { form.get_page("person_1_age") }
+    let(:previous_page_id) { form.get_page("person_1_age") }
     let(:value_check_previous_page) { form.get_page("net_income_value_check") }
 
     it "returns the next page given the previous" do
-      expect(form.next_page(previous_page, lettings_log, user)).to eq("person_1_gender")
+      expect(form.next_page_id(previous_page, lettings_log, user)).to eq("person_1_gender")
     end
 
     context "when the current page is a value check page" do
@@ -33,12 +33,12 @@ RSpec.describe Form, type: :model do
 
       it "returns the previous page if answer is `No` and the page is routed to" do
         lettings_log.net_income_value_check = 1
-        expect(form.next_page(value_check_previous_page, lettings_log, user)).to eq("net_income")
+        expect(form.next_page_id(value_check_previous_page, lettings_log, user)).to eq("net_income")
       end
 
       it "returns the next page if answer is `Yes` answer and the page is routed to" do
         lettings_log.net_income_value_check = 0
-        expect(form.next_page(value_check_previous_page, lettings_log, user)).to eq("net_income_uc_proportion")
+        expect(form.next_page_id(value_check_previous_page, lettings_log, user)).to eq("net_income_uc_proportion")
       end
     end
   end
@@ -54,18 +54,18 @@ RSpec.describe Form, type: :model do
 
       it "returns the previous page if the page is routed to" do
         page_index = page_ids.index("conditional_question_no_second_page")
-        expect(form.previous_page(page_ids, page_index, lettings_log, user)).to eq("conditional_question_no_page")
+        expect(form.previous_page_id(page_ids, page_index, lettings_log, user)).to eq("conditional_question_no_page")
       end
 
       it "returns the page before the previous one if the previous page is not routed to" do
         page_index = page_ids.index("conditional_question_no_page")
-        expect(form.previous_page(page_ids, page_index, lettings_log, user)).to eq("conditional_question")
+        expect(form.previous_page_id(page_ids, page_index, lettings_log, user)).to eq("conditional_question")
       end
     end
   end
 
   describe "next_page_redirect_path" do
-    let(:previous_page) { form.get_page("net_income") }
+    let(:previous_page_id) { form.get_page("net_income") }
     let(:last_previous_page) { form.get_page("housing_benefit") }
     let(:previous_conditional_page) { form.get_page("conditional_question") }