对带有 promise 链的 nodejs class 进行单元测试

Question

Can you please help me to write unit test for Publish method. It should cover the line mentioned left side.

The import statement 'amqplib' need to be mocked in jest.

ch.publish and conn.close, etc should be asserted

import { Injectable, Inject } from '@nestjs/common';
import * as amqp from 'amqplib';
import { RabbitMQOptions } from '../interface';
import { RABBITMQ_OPTIONS } from '../constant';

@Injectable()
export class EmitDirectService {
  constructor(
    @Inject(RABBITMQ_OPTIONS)
    private readonly rabbitMQOptions: RabbitMQOptions[],
  ) {}

  publish(queueName: string, message: string) {
    let rabbitMQOption = this.rabbitMQOptions.filter(x => x.name == queueName);
    if (!rabbitMQOption) {
      throw Error('Connection string does not exist');
    }
    amqp
      .connect(rabbitMQOption[0].connection)
      .then(function(conn) {
        return conn
          .createChannel()
          .then(function(ch) {
            var ex = rabbitMQOption[0].exchangeName;
            var ok = ch.assertExchange(ex, rabbitMQOption[0].exchangeType, {                        // Need Test Coverage
              durable: false,
            });

            return ok.then(function() {                                                             //Need test coverage all subsequent 2 line
              ch.publish(ex, rabbitMQOption[0].key, Buffer.from(message));

              return ch.close();
            });
          })
          .finally(function() {
            conn.close();                                                                           // Need test Coverage
          });
      })
      .catch(console.warn);
  }
}

Answer 1

Ever heard of Google?

AMQP mocking and expectations library, inspired by nock