Add specs for DomainBlockPolicy (#9585)

spec/policies/domain_block_policy_spec.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+require 'pundit/rspec'
+
+RSpec.describe DomainBlockPolicy do
+  let(:subject) { described_class }
+  let(:admin)   { Fabricate(:user, admin: true).account }
+  let(:john)    { Fabricate(:user).account }
+
+  permissions :index?, :show?, :create?, :destroy? do
+    context 'admin' do
+      it 'permits' do
+        expect(subject).to permit(admin, DomainBlock)
+      end
+    end
+
+    context 'not admin' do
+      it 'denies' do
+        expect(subject).to_not permit(john, DomainBlock)
+      end
+    end
+  end
+end