Correspondence is a framework for creating collaborative applications. This makes for some interesting unit testing.

[TestClass]
public class ModelTest
{
    private Community _communityFlynn;
    private Community _communityAlan;
    private Identity _identityFlynn;
    private Identity _identityAlan;

    [TestInitialize]
    public void Initialize()
    {
        var sharedCommunication = new MemoryCommunicationStrategy();
        _communityFlynn = new Community(new MemoryStorageStrategy())
            .AddCommunicationStrategy(sharedCommunication)
            .Register<CorrespondenceModel>()
            .Subscribe(() => _identityFlynn)
            .Subscribe(() => _identityFlynn.MessageBoards)
            ;
        _communityAlan = new Community(new MemoryStorageStrategy())
            .AddCommunicationStrategy(sharedCommunication)
            .Register<CorrespondenceModel>()
            .Subscribe(() => _identityAlan)
            .Subscribe(() => _identityAlan.MessageBoards)
            ;

        _identityFlynn = _communityFlynn.AddFact(new Identity("flynn"));
        _identityAlan = _communityAlan.AddFact(new Identity("alan"));
        _identityFlynn.JoinMessageBoard("The Grid");
        _identityAlan.JoinMessageBoard("The Grid");
    }

    [TestMethod]
    public void InitiallyNoMessages()
    {
        Assert.IsFalse(_identityAlan.MessageBoards.Single().Messages.Any());
    }

    [TestMethod]
    public void FlynnSendsAMessage()
    {
        _identityFlynn.MessageBoards.Single().SendMessage("Reindeer flotilla");

        Synchronize();

        Message message = _identityAlan.MessageBoards.Single().Messages.Single();
        Assert.AreEqual("Reindeer flotilla", message.Text);
    }

    private void Synchronize()
    {
        while (_communityFlynn.Synchronize() || _communityAlan.Synchronize()) ;
    }
}