Mock HttpContext for unit testing a .NET core MVC controller?

Question

I have a function in a controller that I am unit testing that expects values in the header of the http request. I can't initialize the HttpContext because it is readonly.

My controller function expects a http request header value for "device-id"

[TestMethod]
public void TestValuesController()
{
    ValuesController controller = new ValuesController();

    //not valid controller.HttpContext is readonly
    //controller.HttpContext = new DefaultHttpContext(); 

    var result = controller.Get();
    Assert.AreEqual(result.Count(), 2);
}

Is there a straight-forward way to do this without using a third party library?

Answer 1

I was able to initialize the httpcontext and header in this way:

[TestMethod]
public void TestValuesController()
{
    ValuesController controller = new ValuesController();
    controller.ControllerContext = new ControllerContext();
    controller.ControllerContext.HttpContext = new DefaultHttpContext();
    controller.ControllerContext.HttpContext.Request.Headers["device-id"] = "20317";
    var result = controller.Get();
    //the controller correctly receives the http header key value pair device-id:20317
    ...
}