Fix validations of reactions limit (#12955)

spec/validators/reaction_validator_spec.rb

@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe ReactionValidator do
+  let(:announcement) { Fabricate(:announcement) }
+
+  describe '#validate' do
+    it 'adds error when not a valid unicode emoji' do
+      reaction = announcement.announcement_reactions.build(name: 'F')
+      subject.validate(reaction)
+      expect(reaction.errors).to_not be_empty
+    end
+
+    it 'does not add error when non-unicode emoji is a custom emoji' do
+      custom_emoji = Fabricate(:custom_emoji)
+      reaction = announcement.announcement_reactions.build(name: custom_emoji.shortcode, custom_emoji_id: custom_emoji.id)
+      subject.validate(reaction)
+      expect(reaction.errors).to be_empty
+    end
+
+    it 'adds error when 8 reactions already exist' do
+      %w(🐘 ❤️ 🙉 😍 😋 😂 😞 👍).each do |name|
+        announcement.announcement_reactions.create!(name: name, account: Fabricate(:account))
+      end
+
+      reaction = announcement.announcement_reactions.build(name: '😘')
+      subject.validate(reaction)
+      expect(reaction.errors).to_not be_empty
+    end
+
+    it 'does not add error when new reaction is part of the existing ones' do
+      %w(🐘 ❤️ 🙉 😍 😋 😂 😞 👍).each do |name|
+        announcement.announcement_reactions.create!(name: name, account: Fabricate(:account))
+      end
+
+      reaction = announcement.announcement_reactions.build(name: '😋')
+      subject.validate(reaction)
+      expect(reaction.errors).to be_empty
+    end
+  end
+end