Check date input format

app/controllers/form_controller.rb

@@ -141,7 +141,8 @@ private
         day, month, year = params[@log.log_type][question.id].split("/")
         next unless [day, month, year].any?(&:present?)
 
-        result[question.id] = if Date.valid_date?(year.to_i, month.to_i, day.to_i) && year.to_i.positive?
+        date_matches_format = params[@log.log_type][question.id].match?(/\A\d{1,2}\/\d{1,2}\/\d{4}\z/)
+        result[question.id] = if date_matches_format && Date.valid_date?(year.to_i, month.to_i, day.to_i) && year.to_i.positive?
                                 Date.new(year.to_i, month.to_i, day.to_i)
                               else
                                 Date.new(0, 1, 1)

config/locales/en.yml

@@ -124,7 +124,7 @@ en:
         location:
           attributes:
             startdate:
-              invalid: "Enter a date in the correct format, for example 31 1 2022."
+              invalid: "Enter a date in the correct format, for example 31/1/2022."
             units:
               blank: "Enter the total number of units at this location."
             type_of_unit:

config/locales/validations/shared.en.yml

@@ -18,4 +18,4 @@ en:
       postcode: "Enter a postcode in the correct format, for example AA1 1AA."
 
       date:
-        invalid_date: "Enter a date in the correct format, for example 31 1 2024."
+        invalid_date: "Enter a date in the correct format, for example 31/1/2024."

spec/requests/form_controller_spec.rb

@@ -619,6 +619,25 @@ RSpec.describe FormController, type: :request do
             end
           end
 
+          context "when the date input doesn't match the required format" do
+            let(:page_id) { "tenancy_start_date" }
+            let(:params) do
+              {
+                id: lettings_log.id,
+                lettings_log: {
+                  page: page_id,
+                  "startdate" => "31620224352342",
+                },
+              }
+            end
+
+            it "validates the date correctly" do
+              post "/lettings-logs/#{lettings_log.id}/#{page_id.dasherize}", params: params
+              follow_redirect!
+              expect(page).to have_content("There is a problem")
+            end
+          end
+
           context "when allow_future_form_use? is enabled" do
             before do
               allow(FeatureToggle).to receive(:allow_future_form_use?).and_return(true)
@@ -631,7 +650,7 @@ RSpec.describe FormController, type: :request do
                   id: lettings_log.id,
                   lettings_log: {
                     page: page_id,
-                    "startdate" => "1/1/1",
+                    "startdate" => "1/1/1000",
                   },
                 }
               end
@@ -652,7 +671,7 @@ RSpec.describe FormController, type: :request do
                   id: sales_log.id,
                   sales_log: {
                     page: page_id,
-                    "saledate" => "1/1/1",
+                    "saledate" => "1/1/1000",
                   },
                 }
               end