After lengthy discussion, I think we agreed this would be better presented as something like:

    TestName.new("name") do |t|
      t.add_sip_endpoint
      t.add_quaff_endpoint do
        ...code...
      end
    end

With the `add_quaff_endpoint` dealing with fiddling with `quaff_lambdas` (so you no longer need to expose them on the TestDefinition interface.