我想用jest测试我的middy中间件的lambda处理器，在中间件中我给request.event分配了一个属性，然后在处理器中使用。

//hander.ts 

const main = async (event: APIGatewayProxyEvent): Promise<APIGatewayProxyResult> => {
  return {
    statusCode: 200,
    body: `some`
  };
};

export const handler = middy(main)
  .use(myCustomMiddware('somedata'));

// myCustomMiddleware.ts
export const myCustomMiddleware = (data: string): middy.MiddlewareObj<APIGatewayProxyEvent, APIGatewayProxyResult> => {
  const before: middy.MiddlewareFn<APIGatewayProxyEvent, APIGatewayProxyResult> = async (request): Promise<void> => {
    // Do stuff
    Object.assign(request.event, { importantData: 'important' } as { importantData: string });
  };
};
return {
  before
};

现在我想写一个测试，看看处理程序是否接收到正确的值：

// in my .test.ts file

describe('test', () => {
  const mockHandler = jest.fn(async (event: APIGatewayProxyEvent): Promise<APIGatewayProxyResult> => {
    return {
      statusCode: 200,
      body: ''
    };
  });

  it('event should contain assigned value', () => {
    const request = {
      event: {
        requestContext: {
          authorizer: {
            claims: {
              'custom:SomeClaimA': 'claimA',
              'custom:SomeClaimB': '1'
            }
          }
        }
      }
    };

    const middleware = middy(mockHandler).use(myCustomMiddleware('somedata'));
    await middleware.before(request as never);

    expect(mockHandler).toHaveBeenCalledWith(expect.objectContaining({ importantData:'important'} ));
  });

但是由于某种原因，jest告诉我importantData不是接收参数的一部分，而实际上它是接收参数的一部分。

Error: expect(jest.fn()).toHaveBeenCalledWith(...expected)

Expected: ObjectContaining {"importantData": "important"}
Received: {"importantData": "important", "requestContext": {"authorizer": {"claims": {"custom:SomeClaimA": "SomeClaimA", "custom:SomeClaimB": "1"}}}}, {}