Add service to revoke inclusion in a Collection (#38026)

spec/services/revoke_collection_item_service_spec.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe RevokeCollectionItemService do
+  subject { described_class.new }
+
+  let(:collection_item) { Fabricate(:collection_item) }
+
+  it 'revokes the collection item and sends a Delete activity' do
+    expect { subject.call(collection_item) }
+      .to change { collection_item.reload.state }.from('accepted').to('revoked')
+  end
+
+  context 'when the collection is remote', feature: :collections_federation do
+    let(:collection) { Fabricate(:remote_collection) }
+    let(:collection_item) { Fabricate(:collection_item, collection:, uri: 'https://example.com') }
+
+    it 'federates a `Delete` activity' do
+      subject.call(collection_item)
+
+      expect(ActivityPub::AccountRawDistributionWorker).to have_enqueued_sidekiq_job
+    end
+  end
+end