Extract #all_emoji? to a Rails ext

app/models/conversation/message.rb

@@ -1,8 +1,6 @@
 class Conversation::Message < ApplicationRecord
   include Pagination, Broadcastable, ClientIdentifiable, Promptable, Respondable
 
-  ALL_EMOJI_REGEX = /\A(\p{Emoji_Presentation}|\p{Extended_Pictographic}|\uFE0F)+\z/u
-
   has_rich_text :content
 
   belongs_to :conversation, inverse_of: :messages
@@ -10,12 +8,13 @@ class Conversation::Message < ApplicationRecord
 
   enum :role, %w[ user assistant ].index_by(&:itself)
 
+  validates :content, presence: true
   validates :client_message_id, presence: true
 
   scope :ordered, -> { order(created_at: :asc, id: :asc) }
 
   def all_emoji?
-    content.to_plain_text.match?(ALL_EMOJI_REGEX)
+    content.to_plain_text.all_emoji?
   end
 
   def to_partial_path

app/models/reaction.rb

@@ -6,9 +6,7 @@ class Reaction < ApplicationRecord
 
   after_create :register_card_activity
 
-  def all_emoji?
-    content.match? /\A(\p{Emoji_Presentation}|\p{Extended_Pictographic}|\uFE0F)+\z/u
-  end
+  delegate :all_emoji?, to: :content
 
   private
     def register_card_activity

lib/rails_ext/string.rb

@@ -0,0 +1,5 @@
+class String
+  def all_emoji?
+    self.match?(/\A(\p{Emoji_Presentation}|\p{Extended_Pictographic}|\uFE0F)+\z/u)
+  end
+end

test/lib/rails_ext/string_test.rb

@@ -0,0 +1,11 @@
+require "test_helper"
+
+class StringTest < ActiveSupport::TestCase
+  test "#all_emoji?" do
+    assert "😊".all_emoji?
+    assert "😊😊😊".all_emoji?
+
+    assert_not "Hello 😊".all_emoji?
+    assert_not "Hello".all_emoji?
+  end
+end