Question

I think it’s a good practise to always return empty lists or arrays instead of null when a method comes up with no results to avoid null checks in the code.

Because Rhino Mocks returns the default value for an object, which is null for lists and arrays, a lot of times I have to either add the null checks back in or setup the mocks with expectations to return lists.

Is there a way to configure or extend Rhino Mocks with this behaviour?

var repositoryMock = MockRepository.GenerateMock<ICustomerRepository>(); IList<Customer> customers = repositoryMock.getCustomers();  Assert.IsNotNull(customers); Assert.AreEqual(0, customers.Count ); 

Answer 1

Turns out that this behaviour is possible with Moq as long as the returned object is IEnumerable. The following tests pass:

[Test] public void EmptylListTest() {     var repositoryMock = new Mock<ICustomerRepository>();      IEnumerable<Customer> customers = repositoryMock.Object.GetCustomers();      Assert.IsNotNull(customers);     Assert.AreEqual(0, customers.Count()); }  [Test] public void EmptyArrayTest() {     var repositoryMock = new Mock<ICustomerRepository>();      Customer[] customerArray = repositoryMock.Object.GetCustomerArray();      Assert.IsNotNull(customerArray);     Assert.AreEqual(0, customerArray.Length); }  public interface ICustomerRepository {     IEnumerable<Customer> GetCustomers();     Customer[] GetCustomerArray(); }