A simple BDD “framework”

Last month I held a WPF presentation at work where I created a ViewModel class doing TDD. This got a little buzz because of the way I integrated BDD concepts in the tests. I have since then recieved a few question about how I actually did it. Let’s first have a look at what I did:

namespace Specifications_for_customer_search
{
    [Scenario]
    public class When_user_searches_for_customers : ScenarioBase
    {
        private RhinoAutoMocker<CustomerSearchViewModel> _mocks;
        private List<Customer> _customers;
        private string _customerName;

        public override void Given()
        {
            _mocks = new RhinoAutoMocker<CustomerSearchViewModel>();
            _customerName = "goran";
            _customers = new List<Customer> { new Customer(_customerName) };
            _mocks.Get<ICustomerRepository>().Stub(me => me.FindCustomerByName(Arg<string>.Is.Anything)).Return(_customers);
            
        }

        public override void When()
        {
            _mocks.ClassUnderTest.SearchCommand.Execute(_customerName);
        }

        [Then]
        public void should_query_customer_repository_for_matching_customers()
        {
            _mocks.Get<ICustomerRepository>().AssertWasCalled(me => me.FindCustomerByName(_customerName));
        }

        [Then]
        public void should_list_customers_found()
        {
            Assert.That(_mocks.ClassUnderTest.Customers, Is.EqualTo(_customers));
        }
    }
}

This was all done by using the base class from my previous post and renaming Arrange and Assert to Given and When. In this example I used NUnit, so I inherited from NUnit’s test attributes:

public class ThenAttribute : TestAttribute{}
public class ScenarioAttribute : TestFixtureAttribute { }

That was all. Happy testing! :)