Pending example models minimal coverage (#23912)

spec/models/custom_emoji_category_spec.rb

@@ -2,6 +2,13 @@
 
 require 'rails_helper'
 
-RSpec.describe CustomEmojiCategory, type: :model do
-  pending "add some examples to (or delete) #{__FILE__}"
+describe CustomEmojiCategory do
+  describe 'validations' do
+    it 'validates name presence' do
+      record = described_class.new(name: nil)
+
+      expect(record).to_not be_valid
+      expect(record).to model_have_error_on_field(:name)
+    end
+  end
 end