Add ObjectStore::Item model

This inherits the edition model and sets a few defaults to
override some Edition defaults. It also contains an
`add_field_accessors` callback that reads the configuration for a
given item_type and sets the relevant variables using
[`store_accessor`][1]. Additionally, if the field is required, we set
validation on the object too.

[1]: https://api.rubyonrails.org/classes/ActiveRecord/Store.html

app/models/object_store/item.rb

@@ -0,0 +1,33 @@
+module ObjectStore
+  class Item < Edition
+    store_accessor :details, :item_type
+
+    after_initialize :add_field_accessors
+
+    def summary_required?
+      false
+    end
+
+    def body_required?
+      false
+    end
+
+    def previously_published
+      false
+    end
+
+  private
+
+    def add_field_accessors
+      properties = ObjectStore.fields_for_item_type(item_type)
+      properties.each_key do |k|
+        singleton_class.class_eval { store_accessor :details, k }
+        if ObjectStore.field_is_required?(item_type, k)
+          singleton_class.class_eval { validates k, presence: true }
+        end
+      end
+    rescue UnknownItemType
+      # Ignored
+    end
+  end
+end

test/factories.rb

@@ -2,4 +2,4 @@ def image_fixture_file
   @image_fixture_file ||= File.open(Rails.root.join("test/fixtures/minister-of-funk.960x640.jpg"))
 end
 
-Dir[Rails.root.join("test/factories/*.rb")].sort.each { |f| require f }
+Dir[Rails.root.join("test/factories/**/*.rb")].sort.each { |f| require f }

test/factories/object_store/item.rb

@@ -0,0 +1,11 @@
+FactoryBot.define do
+  factory :object_store_item, class: ObjectStore::Item, parent: :edition do
+    transient do
+      item_type { "email_address" }
+    end
+
+    title { "object-store-item" }
+
+    initialize_with { ObjectStore::Item.new(item_type:) }
+  end
+end

test/unit/app/models/object_store/item_test.rb

@@ -0,0 +1,30 @@
+require "test_helper"
+
+class ObjectStore::ItemTest < ActiveSupport::TestCase
+  setup do
+    @item = build(:object_store_item, item_type: "email_address")
+  end
+
+  test "it creates accessors for an email address" do
+    @item.email_address = "[email protected]"
+
+    assert_equal @item.email_address, "[email protected]"
+  end
+
+  test "it validates the presence of an email address" do
+    assert_not @item.valid?
+    assert @item.errors[:email_address].any?
+  end
+
+  test "#summary_required? returns false" do
+    assert_equal @item.summary_required?, false
+  end
+
+  test "#body_required? returns false" do
+    assert_equal @item.body_required?, false
+  end
+
+  test "#previously_published returns false" do
+    assert_equal @item.previously_published, false
+  end
+end