C# Visual Studio Unit Test, Mocking up a client IP address

Question

Hey guys,

I am writing some unit tests and I'm getting an exception thrown from my real code when trying to do the following:

string IPaddress = HttpContext.Current.Request.UserHostName.ToString();

Is there a way to mock up an IP address without rewriting my code to accept IP address as a parameter?

Thanks!

Answer 1

Take a look at Dependency Injection.

Basically you get around such issues by pushing the data into a class with (for example in this case) a "context" or "settings" class.

public interface IAppContext
{
  string GetIP();
}

You then have a prod implementation that does the real thing and a mock or fake in you tests.

public class AppContext : IAppConext
{
  public string GetIP()
  {
    return HttpContext.Current.Request.UserHostName.ToString();
  }
}

The app context gets pushed into the class using the ip address...

Oh- and as far as I know there is no inbuilt mocking for any VS editions, you will need to check out one of the many - Rhino mocks, Moq... there are many! Also see typemock but it takes a different approach.

PK :-)