问如何在jest测试中模拟节点'createReadStream‘和'readline.createInterface’

EN

private createReadStreamSafe(filePath: string): Promise<fs.ReadStream> {
        return new Promise((resolve, reject) => {
          const fileStream = fs.createReadStream(filePath)
          console.log('file Stream')
          fileStream
            .on('error', () => {
              reject('create read stream error')
            })
            .on('open', () => {
              resolve(fileStream)
            })
        })
      }
    
      async start() {
        const fileStream = await this.createReadStreamSafe(this.filePath)
    
        const rl = readline.createInterface({
          input: fileStream,
          output: process.stdout,
          terminal: false
        })
    
        for await (const line of rl) {
          ...
        }
      }

it.only('should create an error if creating the read stream from the file path fails', () => {
    const mockedReadStream = new Readable()
    jest.spyOn(fs, 'createReadStream').mockReturnValue(mockedReadStream as any)
    const app = createApp('invalid/file/path')

    expect.assertions(1)
    try {
      app.start()
      mockedReadStream.emit('error', 'Invalid file path')
    } catch (error) {
      expect(getErrorMessage(error)).toBe('Invalid file path')
    }
  })

node:internal/process/promises:246
          triggerUncaughtException(err, true /* fromPromise */);
          ^

[UnhandledPromiseRejection: This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). The promise rejected with the reason "undefined".] {
  code: 'ERR_UNHANDLED_REJECTION'
}
node:internal/process/promises:246
          triggerUncaughtException(err, true /* fromPromise */);