如何测试调用异步方法的Controller ActionResult

Question

我想对MVC控制器的最终ViewResult进行单元测试。
控制器代码作为应用程序运行时似乎可以正常工作。但是，当调试下面的单元测试方法时，它将开始逐步浏览控制器代码，并且当到达控制器中的这一行时，它似乎返回了单元测试。

HttpResponseMessage result = await getslots.GetDataFromIDMSapi(ssapiuri);

此行下的其余控制器代码未执行。因此，ViewResult不会返回到单元测试。

正在使用的测试框架是Microsoft.VisualStudio.TestTools.UnitTesting。

控制器方法

public async Task<ActionResult> Details(string positionNbr)
{
    if (string.IsNullOrWhiteSpace(positionNbr))
    {
        throw new HttpException(400, "BadRequest");
    }

    string ssapiuri = getslots.BuildAPIuri($"/current/?positionNbr={positionNbr}");

    HttpResponseMessage result = await getslots.GetDataFromIDMSapi(ssapiuri);
    //right after executing the above, control is returned to the test method

    if (result.StatusCode != HttpStatusCode.OK)
    {
        throw new HttpException(404, "NotFound");
    }


    XDocument doc = XDocument.Load(result.Content.ReadAsStreamAsync().Result);


    IDMSElements elements = getslots.CopyDocToElements(doc);

    PositionSlots myslots = (PositionSlots)elements;
    myslots.UpdateDetails(db);


    var model = new PositionSlot_vm();
    model.PositionSlot = myslots.Positions.FirstOrDefault();
    return View("Details", model);

}

称为异步方法

public async Task<HttpResponseMessage> GetDataFromIDMSapi(string ssapiuri) 
{      
   HttpResponseMessage result = await MvcApplication.httpClientInstance.GetAsync(ssapiuri);

    return result;
}

测试方法

public async Task Details_Given_Valid_Id_Can_Get_Position_Details()
{
    //Arrange - create the controller
    PositionController target = new PositionController();

    //Act 
    //the next line starts going through the controller code
    var viewResult = await  target.Details(idToTest) as ViewResult;

       PositionSlot_vm ps = viewResult.ViewData.Model as PositionSlot_vm;

    //Assert
    Assert.IsInstanceOfType(viewResult.ViewData.Model,typeof(PositionSlot_vm));
    Assert.AreEqual(456, ps.PositionSlot.CostCenter);
    Assert.AreEqual(123, ps.PositionSlot.EmployeeId);
    Assert.AreEqual("xxx", ps.Department.DepartmentName);

}