ASP.NET MVC – Getting User Input in Your Controller

Even for something so simple, a unit test will serve multiple purposes

1. Confidence, what was written conforms to expected output. It may seem trivial to verify that it returns the correct view, but the result is objective evidence that the requirement was met
2. Regression testing. Should the Create method need to change, you still have a unit test for the expected output. Yes, the output could change along and that results in a brittle test but it still is a check against un-managed change control

For that particular action I'd test for the following

1. What happens if _myService is null?
2. What happens if _myService.Create throws an Exception, does it throw specific ones to handle?
3. Does a successful _myService.Create return the _Success view?
4. Are errors propagated up to ModelState?

You pointed out checking Request and Model for NullReferenceException and I think the ModelState.IsValid will take care of handling NullReference for Model.

Mocking out the Request allows you to guard against a Null Request which is generally impossible in production I think, but can happen in a Unit Test. In an Integration Test it would allow you to provide different UserHostAddress values (A request is still user input as far as the control is concerned and should be tested accordingly)

I'm not entirely sure I've identified the right problem, but if I have, this may help:

We created a class called ScriptManager which lets us add arbitrary javascript files and/or functions to the bottom of all our pages when they are rendered. Give this a try:

public class ScriptManager
{
    public List<string> scripts = new List<string>();
    public List<string> scriptFiles = new List<string>();
}
public static class HtmlExtensions
{

    [ThreadStatic]
    private static ControllerBase pageDataController;
    [ThreadStatic]
    private static ScriptManager pageData;

    public static ScriptManager ScriptManager(this HtmlHelper html)
    {
        ControllerBase controller = html.ViewContext.Controller;

        // This makes sure we get the top-most controller
        while (controller.ControllerContext.IsChildAction)
        {
            controller = controller.ControllerContext.ParentActionViewContext.Controller;
        }
        if (pageDataController == controller)
        {
            // We've been here before
            return pageData;
        }
        else
        {
            // Initial setup
            pageDataController = controller;
            pageData = new ScriptManager();
            return pageData;
        }
    }
}

Then, at the bottom of your _Layout.cshtml page:

@foreach (var script in Html.ScriptManager().scriptFiles.Distinct())
{
    @Html.Script(script);
}
@foreach (var script in Html.ScriptManager().scripts)
{
    @Html.Raw("<script type='text/javascript'>")
    @Html.Raw(script)
    @Html.Raw("</script>")
}

Finally, you use it in a partial view like:

@{
  Html.ScriptManager().scriptFiles.Add(Url.Content("~/Scripts/jquery.blockUI.js"));
 }

You lose the ability to tell the client about the scripts in the header of the page, but they will be included on all pages you use a partial view that uses the blockUI (for example).