fix: Update associations when a label is updated (#3046)

spec/services/labels/update_service_spec.rb

@@ -0,0 +1,32 @@
+require 'rails_helper'
+
+describe Labels::UpdateService do
+  let(:account) { create(:account) }
+  let(:conversation) { create(:conversation, account: account) }
+  let(:label) { create(:label, account: account) }
+  let(:contact) { conversation.contact }
+
+  before do
+    conversation.label_list.add(label.title)
+    conversation.save!
+
+    contact.label_list.add(label.title)
+    contact.save!
+  end
+
+  describe '#perform' do
+    it 'updates associated conversations/contacts labels' do
+      expect(conversation.label_list).to eq([label.title])
+      expect(contact.label_list).to eq([label.title])
+
+      described_class.new(
+        new_label_title: 'updated-label-title',
+        old_label_title: label.title,
+        account_id: account.id
+      ).perform
+
+      expect(conversation.reload.label_list).to eq(['updated-label-title'])
+      expect(contact.reload.label_list).to eq(['updated-label-title'])
+    end
+  end
+end