Use Rhino Mocks to create an in-memory database for use while developing code and user interface

Question

Hi Everyone,

I've been struggling with this all morning and I may be completely on the wrong track since Rhino Mocks was originally designed for Unit Testing.

However, I have a couple of resusable backend components that handle Authentication and 'Blogging' like features of a website, each contains their own data access layer. While developing the user interface, I really don't want to be messing around with creating test data in a database and / or an XML file.

What I'm striving for is an implementation of my data access interfaces (IBlogRepository), for example to run as singletons throughout the lifetime of a debugging session (aka an in-memory database) so that I can display some data to design against.

Hope that makes sense! All comments greatly appreciated.

Jason

Answer 1

Don't use a mock, actually create a test implementation of your IBlogRepository interface, which returns hard-coded dummy data.

Answer 2

Singletons are at odds with Testability because they are so hard to change. You would be much better off using Dependency Injection to inject an IBlogRepository instance into your consuming classes:

public class MyClass
{
    private readonly IBlogRepository repository;

    public MyClass(IBlogRepository repository)
    {
        if(repository == null)
        {
            throw new ArgumentNullException("repository");
        }

        this.repository = repository;
    }

    // use this.repository in other members
}

Notice how the Guard Claus together with the readonly keyword guarantees that the IBlogRepository instance will always be available.

This will allow you to use Rhino Mocks or another dynamic mock library to inject Test Doubles of IBlogRepository into the consuming classes.