Pull in all of the specifications in the test assembly.

SpecificationFixture.cs

[TestFixture]
public class SpecificationFixture
{
    [Test, TestCaseSource("GetSpecificationTestCases")]
    public void Verify(SpecificationToRun spec)
    {
        var runner = new SpecificationRunner();
            
        RunResult result = runner.RunSpecifciation(spec);
        if (result.Passed)
            return;

        Assert.Fail(Format(result));
    }

    public TestCaseData[] GetSpecificationTestCases()
    {
        RootGenerator generator = new RootGenerator(Assembly.GetExecutingAssembly());

        IEnumerable<SpecificationToRun> specs = generator.GetSpecifications();
        return specs.Select(AsTestCaseData).ToArray();
    }

    static TestCaseData AsTestCaseData(SpecificationToRun spec)
    {
        var data = new TestCaseData(spec);
        data.SetName(spec.Specification.GetName());
        return data;
    }

    private static string Format(RunResult result)
    {
        var ret = "\n\nSPECIFICATION: " + (result.SpecificationName ?? result.FoundOnMemberInfo.Name) + " ";
            
        ret += (result.Passed ? "PASSED" : "FAILED") + " " + result.Message + "\n\n";
        if (result.Thrown != null)
            ret += result.Thrown + "\n\n";

        ret += "\tEXPECTATIONS:\n\t-------------\n";

        foreach (var exp in result.Expectations)
        {
            if (!exp.Passed)
                ret += "\n\t<<<----------\n";

            ret += "\t" + exp.Text + " " + (exp.Passed ? "PASSED" : "FAILED") + "\n";

            if (!exp.Passed)
            {
                ret += PadMultiLineText(exp.Exception.Message) + "\n\n";
                ret += "\t>>>----------\n\n";
            }
        }

        return ret;
    }

    static string PadMultiLineText(string txt)
    {
        string[] lines = txt.Split(new[] {"\n"}, StringSplitOptions.None);
        return lines.Aggregate("", (current, line) => current + ("\t" + line + "\n"));
    }
}