Introduction to Mocks & Dependency Swapping

Notes Used to Craft this Lesson

So, what about if our service has a dependency? For example, our NotificationService depends on the AdonisJS logger.

// app/services/notification_service.ts
import { inject } from "@adonisjs/core";
import { Logger } from "@adonisjs/core/logger";

@inject()
export default class NotificationService {
  constructor(protected logger: Logger) {} // 👈

  /**
   * Simulates sending a notification with the given message.
   * This is a placeholder for an actual notification service.
   * It will log the message and then wait for 5 milliseconds before resolving.
   *
   * @param message - The message to be sent in the notification.
   */
  async send(message: string) {
    this.logger.info("Simulating notification %s", message);

    await new Promise((resolve) => setTimeout(resolve, 5));
  }
}