Ensure presence gets a valid value

app/models/event.rb

@@ -19,6 +19,7 @@ class Event < ApplicationRecord
   include WithTimezone
 
   before_validation :fix_keywords, on: :create, if: :scraper_record
+  before_validation :presence_default
   before_save :check_country_name # :set_default_times
   before_save :geocoding_cache_lookup, if: :address_will_change?
   after_save :enqueue_geocoding_worker, if: :address_changed?
@@ -124,6 +125,7 @@ class Event < ApplicationRecord
   validates :latitude, numericality: { greater_than_or_equal_to: -90, less_than_or_equal_to: 90, allow_nil: true }
   validates :longitude, numericality: { greater_than_or_equal_to: -180, less_than_or_equal_to: 180, allow_nil: true }
   # validates :duration, format: { with: /\A[0-9][0-9]:[0-5][0-9]\z/, message: "must be in format HH:MM" }, allow_blank: true
+  validates :presence, inclusion: { in: presences.keys, allow_blank: true }
   validate :allowed_url
   clean_array_fields(:keywords, :fields, :event_types, :target_audience,
                      :eligibility, :host_institutions, :sponsors)
@@ -495,4 +497,8 @@ def fix_keywords
       end
     end
   end
+
+  def presence_default
+    self.presence = :onsite if presence.blank?
+  end
 end

test/models/event_test.rb

@@ -571,20 +571,87 @@ class EventTest < ActiveSupport::TestCase
   end
 
   test 'can still set presence through online setter' do
+    assert @event.valid?
     assert @event.onsite?
     refute @event.online?
     refute @event.hybrid?
 
     @event.online = true
 
+    assert @event.valid?
     refute @event.onsite?
     assert @event.online?
     refute @event.hybrid?
 
     @event.online = false
 
+    assert @event.valid?
     assert @event.onsite?
     refute @event.online?
     refute @event.hybrid?
+
+    @event.online = ''
+
+    assert @event.valid?
+    assert @event.onsite?
+    refute @event.online?
+    refute @event.hybrid?
+  end
+
+  test 'validates presence' do
+    @event.presence = 'onsite'
+
+    assert @event.valid?
+    assert @event.onsite?
+    refute @event.online?
+    refute @event.hybrid?
+
+    @event.presence = 0
+
+    assert @event.valid?
+    assert @event.onsite?
+    refute @event.online?
+    refute @event.hybrid?
+
+    @event.presence = :online
+
+    assert @event.valid?
+    refute @event.onsite?
+    assert @event.online?
+    refute @event.hybrid?
+
+    @event.presence = 1
+
+    assert @event.valid?
+    refute @event.onsite?
+    assert @event.online?
+    refute @event.hybrid?
+
+    @event.presence = 'hybrid'
+
+    assert @event.valid?
+    refute @event.onsite?
+    refute @event.online?
+    assert @event.hybrid?
+
+    @event.presence = nil
+
+    assert @event.valid?
+    assert @event.onsite?
+    refute @event.online?
+    refute @event.hybrid?
+
+    @event.presence = ''
+
+    assert @event.valid?
+    assert @event.onsite?
+    refute @event.online?
+    refute @event.hybrid?
+
+    # TODO: Use enum validation in Rails 7.1 https://github.com/rails/rails/pull/49100
+    assert_raises(ArgumentError) do
+      @event.presence = 'xyz'
+      refute @event.valid?
+    end
   end
 end