使用 jest 未调用异步等待函数

Question

I am new to jest and i am trying to call await function it return the promise. But i am getting and error like expected calls 1 and received calls is 0

Code:

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

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

}

MockData

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

Test suite

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();
});

After adding shuan's comment, still i am facing an issue is like,

console.error node_modules/zone.js/dist/zone.js:703 Unhandled Promise rejection: Unexpected token o in JSON at position 1 ; Zone: ProxyZone ; Task: Promise.then ; Value: SyntaxError: Unexpected token o in JSON at position 1 at JSON.parse () at 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)

i have updated the test case

MockData

 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',
                }
              });
        }
    }
}

Test suite

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

As Jaromanda correctly wrote, you need to await the asynchronous method. Also, you need to spy on the method before acting not after acting.

Here is a simplified, standalone version of your original example that you can run in Jest.

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();
});