使用模拟测试

您需要将sender.sendMessages函数替换为您可以控制的模拟版本，例如在测试用例中抛出异常。
使用你可以在测试代码中控制的服务、对象或函数的模拟版本来模拟任意条件、状态或错误的技术是一个成熟的最佳实践。你可以在互联网上找到大量关于 * 模拟测试 * 的信息。
有关模拟的一般信息：

• Mock object (Wikipedia)
• Mock Testing (Devopedia)
• What is Mocking? (Stack Overflow)

使用Jest Manual Mocks创建模拟服务总线客户端

实际上，您必须使用Jest手动模拟，以便

1. ServiceBusClient导入将导入模拟版本，而不是真实的版本
   1.模拟版本的createSender方法返回一个模拟发送者。
   1.模拟发送者的sendMessages方法可以在测试中做任何你想让它做的事情（例如抛出一个特定的异常），你可以在测试调用被测代码之前配置模拟来完成。
   以下是一些可以帮助您的Jest和Typescript特定资源：

• Jest Manual Mocks
• Customisable manual mocks in Jest and Typescript
• Using Jest Mocks + TypeScript the Right Way
• Mocking TypeScript classes with Jest

下面是一个符合您需求的Jest单元测试源代码示例（我希望如此）：

import type { AzureFunction, Context } from '@azure/functions'
import type { ServiceBusSender } from '@azure/service-bus'
import { when } from 'jest-when'

describe('service bus client unit tests', () => {
  const clientConnectionString = 'myConnectionString'
  const topicName = 'myTopic'
  let ServiceBusClient: jest.SpyInstance
  let isServiceBusError: jest.SpyInstance
  let serviceBusClient: { createSender: (topicName: string) => ServiceBusSender }
  let sender: jest.Mocked<ServiceBusSender>
  let func: AzureFunction
  beforeAll(() => {
    ServiceBusClient = jest.fn()
    isServiceBusError = jest.fn()
    serviceBusClient = { createSender: jest.fn() }
    sender = { sendMessages: jest.fn() } as unknown as jest.Mocked<ServiceBusSender>
    jest.doMock('@azure/service-bus', () => ({ ServiceBusClient, isServiceBusError }))
    when(ServiceBusClient).calledWith(clientConnectionString).mockReturnValue(serviceBusClient)
    when(serviceBusClient.createSender).calledWith(topicName).mockReturnValue(sender)
    func = require('./sample').func
    expect(ServiceBusClient).toHaveBeenNthCalledWith(1, clientConnectionString)
    expect(serviceBusClient.createSender).toHaveBeenNthCalledWith(1, topicName)
  })
  afterEach(() => {
    jest.resetAllMocks()
  })
  afterAll(() => {
    jest.restoreAllMocks()
  })
  test('should log error given a service bus error', async () => {
    // Given
    const contextLogError = jest.fn()
    const context = { log: { error: contextLogError } } as unknown as Context
    const messageBody = { body: { a: 'a', b: 'b', c: 'c' } }
    const error: Error & { code?: string } = new Error('oops')
    error.code = 'MyCode'
    when(sender.sendMessages).calledWith(messageBody).mockRejectedValue(error)
    when(isServiceBusError).calledWith(error).mockReturnValue(true)
    // When
    await func(context)
    // Then
    expect(sender.sendMessages).toHaveBeenNthCalledWith(1, messageBody)
    expect(isServiceBusError).toHaveBeenNthCalledWith(1, error)
    expect(contextLogError).toHaveBeenNthCalledWith(
      1,
      'Error Message: This is the error message oops with the reason MyCode',
    )
  })
  test('should log error given any other error', async () => {
    // Given
    const contextLogError = jest.fn()
    const context = { log: { error: contextLogError } } as unknown as Context
    const messageBody = { body: { a: 'a', b: 'b', c: 'c' } }
    const error = new Error('oops')
    when(sender.sendMessages).calledWith(messageBody).mockRejectedValue(error)
    when(isServiceBusError).calledWith(error).mockReturnValue(false)
    // When
    await func(context)
    // Then
    expect(sender.sendMessages).toHaveBeenNthCalledWith(1, messageBody)
    expect(isServiceBusError).toHaveBeenNthCalledWith(1, error)
    expect(contextLogError).toHaveBeenNthCalledWith(1, 'Error Message: Error Encountered')
  })
})