recurly-8.x-1.x-dev/tests/modules/recurly_test_client/recurly_test_client.services.yml

services:
  recurly_test_client.mock_client:
      decorates: 'recurly.client'
      class: Drupal\recurly_test_client\RecurlyMockClientFactory
      arguments: ['@config.factory', '@logger.factory', '@messenger']