public List<RoutingNode> select(int numExpected) {
        msg.setRoute(Route.parse(hop.getName()));
        new RoutingNode(mbus, net, null, handler, msg).send();
        List<RoutingNode> ret = net.removeNodes();
        assertEquals(numExpected, ret.size());
        return ret;
    }
Routes the contained message based on the current setup, and returns the leaf send contexts.

@param numExpected The expected number of leaf nodes.
@return The list of selected send contexts.
documentapi/src/test/java/com/yahoo/documentapi/messagebus/protocol/test/PolicyTestFrame.java