MsTest - Test Controller when using Controller return Json status node not available

I'm trying to write some tests to some of our controllers. To keep it simple I'll use a simple class as example.

Imagine that I've a controller that returns an json object on success using Json function inherited from Controller

[ApiController]
[Route("[controller]")]
public class ExampleController:Controller
{
    [HttpGet]
    public async Task<IActionResult> Get()
    {
        return await Task.FromResult(new OkObjectResult(new {Message="Success"}));
    }

    [HttpGet("json")]
    public async Task<IActionResult> GetJson()
    {
        return await Task.FromResult(Json(new { Message = "Success" }));
    }
}

Then I have the following test methods:

        [TestMethod]
        public void TestOkResult()
        {

            var services = new ServiceCollection();
            services.AddScoped<ExampleController>();
            var controller = services.BuildServiceProvider().GetRequiredService<ExampleController>();
            var result = controller.Get().Result;
            var parsedResult = result as OkObjectResult;
            Assert.IsInstanceOfType<OkObjectResult>(result);
            Assert.AreEqual(200, parsedResult?.StatusCode ?? 500);


        }
        [TestMethod]
        public void TestJsonResult()
        {

            var services = new ServiceCollection();
            services.AddScoped<ExampleController>();
            var controller = services.BuildServiceProvider().GetRequiredService<ExampleController>();
            var result = controller.GetJson().Result;
            var parsedResult = result as JsonResult;
            Assert.IsInstanceOfType<JsonResult>(result);
            Assert.AreEqual(200, parsedResult?.StatusCode ?? 500);

        }

The method TestJsonResult can't assert the status code, because it's always null

Any ideas?