Yep, you’re right. We’ve been doing the latter example in practice. I like asserting individual method calls rather than a bunch of expectations.

Since you are creating a “mock” object for the SmtpClient, you need to verify the expectations that you set on it.

So the arrangement would be:

[code]

protected override void EstablishContext()
    {
        _mockClient = Dependency();
        IOrderSpec stubSpec = Stub();

        _order = new Order();
        _order.Total = 201.0m;

        stubSpec.Stub(x => x.IsMatch(_order)).Return(true);
       
       //expectation up here
      _mockClient.Expect(x => x.Send(Arg.Matches(msg => msg.To[0].Address == "salesdude@email.com")));
        _orderProcessor = new OrderProcessor(_mockClient, stubSpec);
    }

    protected override void Because()
    {
        _orderProcessor.PlaceOrder(_order);
    }

    [Test]
    public void Should_send_the_email_to_the_sales_guy()
    {
        _mockClient.VerifyAllExpectations();
    }

[/code]

If you wanted the AAA they would both have to be “Stubs” and in the Assert block you can have:

[Test]
    public void Should_send_the_email_to_the_sales_guy()
    {
       _stubClient.AssertWasCalled(x=>x.Send( ...));
    }

This is coming from reading this post:
http://ayende.com/Blog/archive/2008/05/16/Rhino-Mocks–Arrange-Act-Assert-Syntax.aspx

and documentation here:
http://ayende.com/wiki/Rhino+Mocks+3.5.ashx#Arrange,Act,Assert

I wrote about it here:
http://morten.lyhr.dk/2008/07/doing-bdd-with-rhino-mocks-aaa-syntax.html

The ContextSpecification comes from a version of NBehave I still haven’t committed to the trunk. I’ll push it out soon after a few more tweaks.