Add lambda to the validations that use model constants

In this way when we need modify the constants model value in the
model/custom folder, adding lambda it will be possible load the new
values.

spec/models/site_customization/content_block_spec.rb

@@ -17,4 +17,14 @@ RSpec.describe SiteCustomization::ContentBlock, type: :model do
     valid_block = build(:site_customization_content_block, name: "top_links", locale: "es")
     expect(valid_block).to be_valid
   end
+
+  it "dynamically validates the valid blocks" do
+    stub_const("#{SiteCustomization::ContentBlock}::VALID_BLOCKS", %w[custom])
+
+    block.name = "custom"
+    expect(block).to be_valid
+
+    block.name = "top_links"
+    expect(block).not_to be_valid
+  end
 end

spec/models/site_customization/image_spec.rb

@@ -33,5 +33,15 @@ describe SiteCustomization::Image do
 
       expect(image).not_to be_valid
     end
+
+    it "dynamically validates the valid images" do
+      stub_const("#{SiteCustomization::Image}::VALID_IMAGES", { "custom" => [223, 80] })
+
+      custom = build(:site_customization_image, name: "custom", image: fixture_file_upload("logo_header.png"))
+      expect(custom).to be_valid
+
+      map = build(:site_customization_image, name: "map", image: fixture_file_upload("custom_map.jpg"))
+      expect(map).not_to be_valid
+    end
   end
 end

spec/models/site_customization/page_spec.rb

@@ -13,4 +13,14 @@ RSpec.describe SiteCustomization::Page, type: :model do
     custom_page = build(:site_customization_page, slug: "as/as*la")
     expect(custom_page).to be_invalid
   end
+
+  it "dynamically validates the valid statuses" do
+    stub_const("#{SiteCustomization::Page}::VALID_STATUSES", %w[custom])
+
+    custom_page.status = "custom"
+    expect(custom_page).to be_valid
+
+    custom_page.status = "published"
+    expect(custom_page).not_to be_valid
+  end
 end