Cavity Unit Testing

I have started a new open source project on google code which I've named Cavity for no particular reason other than it's somewhat memorable: http://code.google.com/p/cavity/ and I plan on pushing up some of the code I use to accelerate and assist development, starting with an internal DSL for unit testing type and property definitions.

I’ve been doing TDD for about 9 years now and have, I admit, derived a somewhat idiosyncratic style which involves asserting all of the external characteristics of a type. I don’t agree with those who argue in favour of not testing properties (I disagree because properties have behaviour and thus ought to be verifiable). I also believe that interface implementations and attribute decorations should be verifiable (which also speaks to my belief in what I call intentional development). However there is a downside to this, which is that asserting type and property definitions is slower than not doing so (obviously) and so I use my unit test DSL to accelerate the process and thus mitigate the impedance. This has been living inside the SimpleWebServices project for a while now but I thought it was time to promote it to a more formal offering and so it is the first library available from Cavity.

To give you a flavour, here are a couple of examples of testing a class and a property:

[Fact]
public void type_definition()
{
    Assert.True(new TypeExpectations<Class1>()
        .DerivesFrom<object>()
        .IsConcreteClass()
        .IsUnsealed()
        .HasDefaultConstructor()
        .Implements<IFoo>()
        .IsDecoratedWith<CustomAttribute>()
        .Result);
}

[Fact]
public void value_definition()
{
    Assert.True(new PropertyExpectations<Class1>("Value")
        .TypeIs<string>()
        .DefaultValueIs("default")
        .Set("example")
        .ArgumentNullException()
        .ArgumentOutOfRangeException(string.Empty)
        .FormatException("invalid")
        .IsNotDecorated()
        .Result);
}

The binaries and source are zipped for download and to see more examples, please visit the wiki:

• TypeExpectations<T>
• PropertyExpectations