Currently the test framework is a single-threaded program which first sends test messages by executing the send shim, then receives them by executing the receive shim. This will work as long as the broker can store messages in queues until the receive shim can retrieve them.
When testing against the Dispatch Router in a brokerless configuration, there is no entity which can store-and-forward messages. For this case, it is necessary that the receiver is first started, and while it is running, the sender then sends messages. This requires concurrent execution of both shims.
The test frameworks need to be modified to allow for the concurrent execution of both shims.