Specs api v1 controllers (#23930)

spec/controllers/api/v1/instances/domain_blocks_controller_spec.rb

@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe Api::V1::Instances::DomainBlocksController do
+  render_views
+
+  describe 'GET #index' do
+    it 'returns http success' do
+      Setting.show_domain_blocks = 'all'
+      get :index
+
+      expect(response).to have_http_status(200)
+    end
+  end
+end