don't display invalid date inputs when getting a validation error (#807)

app/controllers/form_controller.rb

@@ -48,12 +48,7 @@ class FormController < ApplicationController
     form.pages.map do |page|
       define_method(page.id) do |_errors = {}|
         if @case_log
-          if session["errors"]
+          restore_error_field_values
-            JSON(session["errors"]).each do |field, messages|
-              messages.each { |message| @case_log.errors.add field.to_sym, message }
-            end
-          end
-          session["fields"].each { |field, value| @case_log[field] = value } if session["fields"]
           @subsection = @case_log.form.subsection_for_page(page)
           @page = @case_log.form.get_page(page.id)
           if @page.routed_to?(@case_log, current_user)
@@ -70,6 +65,21 @@ class FormController < ApplicationController
 
 private
 
+  def restore_error_field_values
+    if session["errors"]
+      JSON(session["errors"]).each do |field, messages|
+        messages.each { |message| @case_log.errors.add field.to_sym, message }
+      end
+    end
+    if session["fields"]
+      session["fields"].each do |field, value|
+        unless @case_log.form.get_question(field, @case_log).type == "date"
+          @case_log[field] = value
+        end
+      end
+    end
+  end
+
   def responses_for_page(page)
     page.questions.each_with_object({}) do |question, result|
       question_params = params["case_log"][question.id]

spec/features/form/page_routing_spec.rb

@@ -72,4 +72,43 @@ RSpec.describe "Form Page Routing" do
       expect(page).to have_current_path("/logs/#{id}/property-wheelchair-accessible")
     end
   end
+
+  context "when answer is invalid" do
+    it "shows error with invalid value in the field" do
+      visit("/logs/#{id}/property-postcode")
+      fill_in("case-log-postcode-full-field", with: "fake_postcode")
+      click_button("Save and continue")
+
+      expect(page).to have_current_path("/logs/#{id}/property-postcode")
+      expect(find("#case-log-postcode-full-field-error").value).to eq("fake_postcode")
+    end
+
+    it "does not reset the displayed date" do
+      case_log.update!(startdate: "2021/10/13")
+      visit("/logs/#{id}/tenancy-start-date")
+      fill_in("case_log[startdate(1i)]", with: "202")
+      fill_in("case_log[startdate(2i)]", with: "32")
+      fill_in("case_log[startdate(3i)]", with: "0")
+      click_button("Save and continue")
+
+      expect(page).to have_current_path("/logs/#{id}/tenancy-start-date")
+      expect(find_field("case_log[startdate(3i)]").value).to eq("13")
+      expect(find_field("case_log[startdate(2i)]").value).to eq("10")
+      expect(find_field("case_log[startdate(1i)]").value).to eq("2021")
+    end
+
+    it "does not reset the displayed date if it's empty" do
+      case_log.update!(startdate: nil)
+      visit("/logs/#{id}/tenancy-start-date")
+      fill_in("case_log[startdate(1i)]", with: "202")
+      fill_in("case_log[startdate(2i)]", with: "32")
+      fill_in("case_log[startdate(3i)]", with: "0")
+      click_button("Save and continue")
+
+      expect(page).to have_current_path("/logs/#{id}/tenancy-start-date")
+      expect(find_field("case_log[startdate(3i)]").value).to eq(nil)
+      expect(find_field("case_log[startdate(2i)]").value).to eq(nil)
+      expect(find_field("case_log[startdate(1i)]").value).to eq(nil)
+    end
+  end
 end