没有使用 jest 调用异步等待函数

Question

我是 jest 的新手，我正在尝试调用 await 函数以返回承诺。但我收到了错误，如预期的呼叫 1 和收到的呼叫是 0

代码：

public async callDataSourceCommand(dialogData: any, RecipeId: string) {

   const gridItems = await this.dataSourceService.myPromiseMethod(id, collection);

}

模拟数据

 public get dataSourceServiceMock(): any = {
     return {
        myPromiseMethod: function () {
            return Promise.resolve({
                id: '123',
                collection: []
              });
        }
    }
}

测试套件

it('1. Should execute ', async() => {
    const myDialogApp: DialogApp = TestBed.get(DialogApp);
    myDialogApp.selectedOrder = selectedOrder;
    myDialogApp.RecipeId = Recipe.__id;
    myDialogApp.callDataSourceCommand(dialogData, RecipeId);
    jest.spyOn(dataSourceServiceMock, 'myPromiseMethod');
    expect(dataSourceServiceMock.myPromiseMethod).toHaveBeenCalled();
});

添加了shuan的评论后，我仍然面临一个问题，

console.error node_modules/zone.js/dist/zone.js:703 未处理的承诺拒绝：位置 1 的 JSON 中的意外标记 o；区域：代理区域；任务：Promise.then；值：SyntaxError：位置 1 处 JSON 中的意外标记 o 在 JSON.parse() 在 OrderManagementMultipleBatchesDialogApp。 (D:\DCS_WorkSpace\src\DCSPlus\UI\libs\order-management\apps\src\components\order-management-multiple-batches-dialog-app\order-management-multiple-ba tches-dialog-app.factory.ts:102:30)

我已经更新了测试用例

模拟数据

 public get dataSourceServiceMock(): any = {
     return {
        myPromiseMethod: function () {
            return Promise.resolve({
                 selectedOrder: {
                    earlierStartTime: '2/5/2020',
                   __id: 'orderId123'
                },
            batchCollection: {
                  __id: 'b1order 1',
                  masterRecipeName: 'New recipe_V1.0',
                  plannedQuantity: '3',
                  masterRecipeId: 'ns=6;s=4/ProjectData/1',
                  actualQuantity: '1',
                  description: 'batchDesc',
                }
              });
        }
    }
}

测试套件

it('1. Should execute ', async() => {

    const myDialogApp: DialogApp = TestBed.get(DialogApp);
    myDialogApp.selectedOrder = selectedOrder;
    myDialogApp.RecipeId = Recipe.__id;

    jest.spyOn(dataSourceServiceMock, 'myPromiseMethod');

    await myDialogApp.callDataSourceCommand(multipleBatchData, masterRecipeId);

    expect(dataSourceServiceMock.myPromiseMethod).toHaveBeenCalled();
});

Answer 1

正如 Jaromanda 正确写的那样，您需要 await 异步方法。此外，您需要在行动之前而不是在行动之后监视方法。

这是您可以在 Jest 中运行的原始示例的简化、独立版本。

class MyDialogApp {
  constructor(private dataSourceService: any) {}

  public async callDataSourceCommand() {
    await this.dataSourceService.myPromiseMethod();
  }
}

const dataSourceServiceMock = {
  myPromiseMethod: function() {
    return Promise.resolve({
      id: '123',
      collection: []
    });
  }
};

const myDialogApp = new MyDialogApp(dataSourceServiceMock);

it('1. Should execute ', async () => {
  // arrange
  jest.spyOn(dataSourceServiceMock, 'myPromiseMethod');

  // act
  await myDialogApp.callDataSourceCommand();

  // assert
  expect(dataSourceServiceMock.myPromiseMethod).toHaveBeenCalled();
});