How to mock HttpContext.Current.Items with NUnit and Rhino Mocks

Question

I'm using NUnit and RhinoMocks for unit testing on the (WebApi) project.

There is a method I'm trying to write test for, which is supposed to add an item to HttpContext.Current.Items.

public override void OnActionExecuting(HttpActionContext actionContext)
{
    HttpContext.Current.Items.Add("RequestGUID", Guid.NewGuid());
    base.OnActionExecuting(actionContext);
}

I have no idea how can I make HttpContext.Current.Items available to the method when ran from within a test method. How can I achieve this?

Also, how can I check if the item has been added (what kind of assertion can/should I use)

Answer 1

You don't need to refactor your code\use RhinoMocks at all for testing it.

Your UT should be similar to the following example:

[Test]
public void New_GUID_should_be_added_when_OnActionExecuting_is_executing()
{
    //arrange section:
    const string REQUEST_GUID_FIELD_NAME = "RequestGUID";

    var httpContext = new HttpContext(
        new HttpRequest("", "http://google.com", ""),
        new HttpResponse(new StringWriter())
    );

    HttpContext.Current = httpContext;

    //act:
    target.OnActionExecuting(new HttpActionContext());

    //assert section:
    Assert.IsTrue(HttpContext.Current.Items.Contains(REQUEST_GUID_FIELD_NAME));
    var g = HttpContext.Current.Items[REQUEST_GUID_FIELD_NAME] as Guid?;
    if (g == null)
    {
        Assert.Fail(REQUEST_GUID_FIELD_NAME + 
                    " is not a GUID, it is :: {0}", 
                    HttpContext.Current.Items[REQUEST_GUID_FIELD_NAME]);
    }
    Assert.AreNotEqual(Guid.Empty, g.Value);
}

BTW, you can split this test to 2:

1. verifies that the RequestGUID is being populated with a GUID
2. verifies that the GUID is not Guid.Empty