Add tests for REST::AccountSerializer

It was meant to be part of mastodon#23255

spec/serializers/rest/account_serializer_spec.rb

@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe REST::AccountSerializer do
+  let(:role)    { Fabricate(:user_role, name: 'Role', highlighted: true) }
+  let(:user)    { Fabricate(:user, role: role) }
+  let(:account) { user.account}
+
+  subject { JSON.parse(ActiveModelSerializers::SerializableResource.new(account, serializer: REST::AccountSerializer).to_json) }
+
+  context 'when the account is suspended' do
+    before do
+      account.suspend!
+    end
+
+    it 'returns empty roles' do
+      expect(subject['roles']).to eq []
+    end
+  end
+
+  context 'when the account has a highlighted role' do
+    let(:role) { Fabricate(:user_role, name: 'Role', highlighted: true) }
+
+    it 'returns the expected role' do
+      expect(subject['roles'].first).to include({ 'name' => 'Role' })
+    end
+  end
+
+  context 'when the account has a non-highlighted role' do
+    let(:role) { Fabricate(:user_role, name: 'Role', highlighted: false) }
+
+    it 'returns empty roles' do
+      expect(subject['roles']).to eq []
+    end
+  end
+end