ViewResult.StatusCode is null despite explicitly setting it

Question

I have written this controller method and this test.

Controller method:

public async Task<IActionResult> Metric(string type, string source) { // Check existence ... var model = await _context .Metrics .FirstAsync(mt => mt.Type == metricType.AsInt() && mt.Source == source); Response.StatusCode = HttpStatusCode.OK.AsInt(); return View(model); }

Test:

[Fact] public async Task MetricExistsTest() { // Arrange ... // Act var result = await _controller.Metric(Metrics.CpuLoad.ToString(), "source-1"); // Assert var viewResult = Assert.IsType<ViewResult>(result); Assert.Equal(HttpStatusCode.OK.AsInt(), viewResult.StatusCode.Value); var model = Assert.IsAssignableFrom<Metric>( viewResult.ViewData.Model ); }

Now, the problem is here Assert.Equal(HttpStatusCode.OK.AsInt(), viewResult.StatusCode.Value);. The viewResult.StatusCode is indeed null. If I comment that line out, everything works.

What am I doing wrong? Why is it null? Do I properly set Response.StatusCode? How do I verify status code then?

Thank you!

remove Response.StatusCode = HttpStatusCode.OK.AsInt(); from within the action. the default response (in this case the view) should have 200 OK — Nkosi
– Nkosi, Commented Feb 23, 2017 at 20:28
@Nkosi and what if I want to set a custom code, like 204 No Content? — Dmytro Bogatov
– Dmytro Bogatov, Commented Feb 23, 2017 at 20:46
There are action results for that learn.microsoft.com/en-us/aspnet/core/mvc/controllers/actions — Nkosi
– Nkosi, Commented Feb 23, 2017 at 20:48
@Nkosi - finally figured it out! See my answer. And thank you for help! — Dmytro Bogatov
– Dmytro Bogatov, Commented Feb 23, 2017 at 22:06

Dmytro Bogatov · Accepted Answer · 2017-02-23 22:05:05Z

I finally did it! All those who helped me with answers and comments - I very much appreciate it!

It turns out that I had two problems - HttpContext does not exist (unless set manually) in testing environment and Response.StatusCode does not set StatusCode on resulting ViewResult object. (These are my observations, correct me if I'm wrong).

Problem 1 solution:

As simple as setting default HttpContext solves the problem. At least, controller method does not crash because Response is not null anymore.

var controller = new HomeController(); controller.ControllerContext = new ControllerContext(); controller.ControllerContext.HttpContext = new DefaultHttpContext();

Problem 2 solution:

It turns out that I need to set StatusCode explicitly on ViewResult object. For some reason, ASP.Core does not mirror StatusCode from Response object to resulting IActionObject. (Correct me if I'm wrong)

So here is the solution (it's another method on my controller, but it clearly demonstrates the idea):

public async Task<IActionResult> Index() { var model = await _context .Metrics .Where(mt => mt.Type == Metrics.CpuLoad.AsInt()) .ToListAsync(); var result = View(model); result.StatusCode = (model.Any() ? HttpStatusCode.OK : HttpStatusCode.NoContent).AsInt(); return result; }

Note that a 204 response should not have a body/view, though. httpstatuses.com/204: "A 204 response is terminated by the first empty line after the header fields because it cannot contain a message body."
@hangy Very true. Don't get surprised when your browser refuses to load the content of 204 page, or even does not add the URL to history.

Steven Ackley · Accepted Answer · 2017-02-23 19:58:45Z

0

It looks like you should be Asserting the result, not the viewresult

[Fact] public async Task MetricExistsTest() { // Arrange ... // Act var result = await _controller.Metric(Metrics.CpuLoad.ToString(), "source-1"); // Assert var viewResult = Assert.IsType<ViewResult>(result); Assert.Equal(HttpStatusCode.OK.AsInt(), result.StatusCode.Value); var model = Assert.IsAssignableFrom<Metric>( viewResult.ViewData.Model ); }

answered Feb 23, 2017 at 19:58

Steven Ackley

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4 Comments

Dmytro Bogatov Over a year ago

It turns out that Response is null in my controller method. Do you have an idea why? And how to set it properly?

Steven Ackley Over a year ago

You should be able to mock the HTTPResonse stackoverflow.com/questions/9823039/…

Dmytro Bogatov Over a year ago

I was able to set default response object. But still IActionResult does not have .StatusCode, so I cannot write result.StatusCode.Value.

Dmytro Bogatov Over a year ago

Mocking did not work for me, unfortunately, but thank you for the answer!

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