Why use a mocking framework instead of hand-rolling our mocks?

Question

Currently I'm reading a book (Pro ASP.Net Framework).

In this book, the author suggests to use a Moq framework to help to do TDD.

[Test]
public void List_Presents_Correct_Page_Of_Products()
{
    IProductsRepository repository = MockProductsRepository(
        new Product { Name = "P1" }, new Product { Name = "P2" },
        new Product { Name = "P3" }, new Product { Name = "P4" },
        new Product { Name = "P5" }
    );

    ProductsController controller = new ProductsController(repository);
    ...
}


static IProductsRepository MockProductsRepository(params Product[] prods)
{
    // Generate an implementor of IProductsRepository at runtime using Moq
    var mockProductsRepos = new Moq.Mock<IProductsRepository>();
    mockProductsRepos.Setup(x => x.Products).Returns(prods.AsQueryable());
    return mockProductsRepos.Object;
}

In the model layer, we've define a FakeRepository, and a SqlRepository.

The fact is I don't see the advantage of using this moq framework. Why don't we only use our FakeRepository ? Or clear our FakeRepository and add fake product on it ?

At first, I thought that the moq framework was there to generate fake data so you don't have to if you have for example 100 fake objects to generate.

What I miss ?

Answer 1

Some advantages of mock frameworks over hand-rolled mocks:

• The mock behavior is closer to the test code because it is in the test code. This makes tests easier to understand without having to look at other code.
• You don't need to create yet another mock class (or worse: add logic to an existing one) just because you want slightly different behavior.
• You end up writing less boilerplate because you only need to setup the methods you want to mock, while with hand-rolled ones you have to implement the whole interface.

Some disadvantages:

• You have to learn a framework, while anyone can write mocks by hand.
• It is yet another dependency you add to your project.

(This is what I can think of right now. Feel free to edit and add more.)