错误：属性未定义，FakeAsync和tick在Post API调用中不起作用

Question

我正在对API调用进行单元测试，我已经验证了API是否可以正确调用。我收到错误，无法读取未定义的属性。我怀疑这是异步代码的问题。

我的API被调用了两次，几乎需要2000毫秒来完成api请求。所以我加了tick（2500）。

还是我期望（component.Financials.length）.toBe（1）;时仍未定义属性

spec.ts

it('should return one object', fakeAsync(() => {
      var dummyObject : any[];
     dummyObject = [
        {
          account: "shjdhjhs",
          product: "xyz"

        }
      ];
      mockFilter={ account="shjdhjhs"}

      //invoking method and intializing filter data
      compoenent.filter=mockFilter;
      component.Data();
      const req = httpMock.expectOne('/api/getrecords');
      //fails, as this api is called many times
      expect(req.request.method).toBe("POST");
      req.flush( dummyObject);
      tick(2500);
      expect(component.records.length).toBe(1);
      //cannot read property of undefined
      expect(component.records).toEqual( dummyObject);

  }));

ApiCall.ts

Data() {
    this.records = [];

    this.http.post<Device[]>('/api/getrecords', this.filter)
      .subscribe(res => {
        if (res['status'] == "FAILURE") {
          console.log(res);
        } else {
          this.records = res['data'];
          ...
        }
       }