I've been using a home brewed BDD Spec extension for writing BDD style tests in NUnit, and I wanted to see what everyone thought. Does it add value? Does is suck? If so why? Is there something better out there?

Here's the source: https://github.com/mjezzi/NSpec

There are two reasons I created this

1. To make my tests easy to read.
2. To produce a plain english output to review specs.

Here's an example of how a test will look:

-since zombies seem to be popular these days..

Given a Zombie, Peson, and IWeapon:

namespace Project.Tests.PersonVsZombie
{
    public class Zombie
    {

    }

    public interface IWeapon
    {
        void UseAgainst( Zombie zombie );
    }

    public class Person
    {
        private IWeapon _weapon;

        public bool IsStillAlive { get; set; }

        public Person( IWeapon weapon )
        {
            IsStillAlive = true;
            _weapon = weapon;
        }

        public void Attack( Zombie zombie )
        {
            if( _weapon != null )
                _weapon.UseAgainst( zombie );
            else
                IsStillAlive = false;
        }
    }
}

And the NSpec styled tests:

public class PersonAttacksZombieTests
{
    [Test]
    public void When_a_person_with_a_weapon_attacks_a_zombie()
    {
        var zombie = new Zombie();
        var weaponMock = new Mock<IWeapon>();
        var person = new Person( weaponMock.Object );

        person.Attack( zombie );

        "It should use the weapon against the zombie".ProveBy( spec =>
            weaponMock.Verify( x => x.UseAgainst( zombie ), spec ) );

        "It should keep the person alive".ProveBy( spec =>
            Assert.That( person.IsStillAlive, Is.True, spec ) );
    }

    [Test]
    public void When_a_person_without_a_weapon_attacks_a_zombie()
    {
        var zombie = new Zombie();
        var person = new Person( null );

        person.Attack( zombie );

        "It should cause the person to die".ProveBy( spec =>
            Assert.That( person.IsStillAlive, Is.False, spec ) );
    }
}

You'll get the Spec output in the output window:

[PersonVsZombie]

- PersonAttacksZombieTests

    When a person with a weapon attacks a zombie
        It should use the weapon against the zombie
        It should keep the person alive

    When a person without a weapon attacks a zombie
        It should cause the person to die

2 passed, 0 failed, 0 skipped, took 0.39 seconds (NUnit 2.5.5).