Improve invalid date validation

This improves the validation when adding an invalid session date to
improve the experience for users.

Jira-Issue: MAV-2215

Author: thomasleese

app/controllers/draft_sessions_controller.rb

@@ -84,7 +84,21 @@ def handle_dates
           @draft_session.session_dates.delete_at(index)
           jump_to("dates")
         else
-          session_date.assign_attributes(remove_invalid_date(attributes))
+          # We need to do this here to get around the multi-parameter
+          # assignment error being raised if we don't validate before
+          # assignment.
+          year = attributes["value(1i)"]
+          month = attributes["value(2i)"]
+          day = attributes["value(3i)"]
+
+          next if day.blank? && month.blank? && year.blank?
+
+          begin
+            value = Date.new(year.to_i, month.to_i, day.to_i)
+            session_date.assign_attributes(value:)
+          rescue StandardError
+            session_date.errors.add(:value, :blank)
+          end
         end
       end
     end
@@ -160,20 +174,4 @@ def send_invitations_at_validator
         params: update_params
       )
   end
-
-  def remove_invalid_date(hash)
-    return hash if hash.blank?
-
-    keys = %w[value(1i) value(2i) value(3i)]
-
-    if keys.all? { hash.key?(it) }
-      begin
-        Date.new(*keys.map { hash[it].to_i })
-      rescue StandardError
-        keys.each { hash.delete(it) }
-      end
-    end
-
-    hash
-  end
 end

spec/features/manage_school_sessions_spec.rb

@@ -20,6 +20,9 @@
     when_i_click_on_schedule_sessions
     then_i_see_the_dates_page
 
+    when_i_add_an_invalid_date
+    then_i_see_a_validation_error
+
     when_i_choose_the_dates
     then_i_see_the_confirmation_page
 
@@ -205,6 +208,17 @@ def then_i_see_the_dates_page
     expect(page).to have_content("When will sessions be held?")
   end
 
+  def when_i_add_an_invalid_date
+    fill_in "Day", with: "99"
+    fill_in "Month", with: "99"
+    fill_in "Year", with: "99"
+    click_on "Continue"
+  end
+
+  def then_i_see_a_validation_error
+    expect(page).to have_content("Enter a date")
+  end
+
   def when_i_choose_the_dates
     fill_in "Day", with: "10"
     fill_in "Month", with: "03"