custom_field-1.0.x-dev/tests/modules/custom_field_test/custom_field_test.services.yml

services:
  plugin.manager.custom_field_type_test:
    class: Drupal\custom_field_test\PluginManager\FieldTypeTestManager
    autowire: true
    parent: default_plugin_manager

  # Alias to FieldTypeTestManager.
  Drupal\custom_field_test\PluginManager\FieldTypeTestManagerInterface:
    alias: plugin.manager.custom_field_type_test