Rhino.Mocks - the basics

Started using Rhino.Mocks recently (Awesome!!!) - just wanted to list a few of the basics; the official Rhino Mocks Documentation is very good and available here. These examples are a bit rough, they have not been compiled; there may be typos.

using

using Rhino.Mocks;

The mock repository

// use the mock repository to create the mocked objects
MockRepository mocks = new Rhino.Mocks.MockRepository();
// example
System.Object someObject = mocks.CreateMock();
// set up the behaviour you want from calls to your mocked object 
Rhino.Mocks.Expect.Call(someObject.Equals(someParameter)).Return(false);
// then don't forget
mocks.ReplayAll();
// now do stuff that calls your mocked object Equals method
...

Mock a call to the db

// create our mocked repository object - IProductRepository, the real one calls the db
IProductRepository repository = mocks.CreateMock();
// tell rhino.mocks when we call the method GetProduct with the argument 33 to return null
Rhino.Mocks.Expect.Call(repository.GetProduct(33)).Return(null);
// get the mocking ready
mocks.ReplayAll();
// pass our mock to our product service layer
ProductService service = new ProductService(repository);
// service.GetProduct makes a call to the mocked repository.GetProduct which will return null
IProduct product = service.GetProduct(33);
// should be null
Assert.IsNull(product);

Ignore any arguments

// any call to GetProduct will return null no matter the value of the arg
Rhino.Mocks.Expect.Call(repository.GetProduct(null)).Return(null).IgnoreArguments();

mock a method that returns void

IProduct product = new Product("003092", "Sierra Nevada", 6.49);
// this void call will handle our product 003092
Rhino.Mocks.Expect.Call(delegate { repository.Save(product); });
// this void call will handle any argument
Rhino.Mocks.Expect.Call(delegate { repository.Save(null); }).IgnoreArguments();

Handle multiple calls to the same method

IProduct product = new Product("003092", "Sierra Nevada", 6.49);
// note the .Repeat.Any()
Rhino.Mocks.Expect.Call(repository.GetProduct("003092")).Return(product).Repeat.Any();
// send the mock to our product service object
ProductService service = new ProductService(repository);
// find by sku calls GetProduct on the mocked Product repository
IProduct beer = service.FindBySku("003092");
// find decent beer calls GetProduct on the mocked Product repository also
IProduct decentBeer = service.FindDecentBeer();

Partial Mock

// create a partial mock with constructor args (our product repository again)
IProductService service = mocks.PartialMock(repository);
// our test case data
IUser loggedOnUser = new User("John", "Doe", CustomerType.Gold);
// mock product service calls to GetLoggedOnUser
Rhino.Mocks.Expect.Call(service.GetLoggedOnUser()).Return(loggedOnUser);
// get the mocking ready
mocks.ReplayAll();
// now GetDiscount is not a mocked method but it does call the mocked GetLoggedOnUser method
decimal discount = service.GetDiscount();
// assert the result
Assert.AreSame(44.4M, discount, "Gold customer discount not correct?");
// NOTE: this will not work (compile) unless the mocked method GetLoggedOnUser is public