Java 8 rabbitmq-akka流的PowerMockito测试

我正在使用由提供的RabbitMq库编写一些测试用例

io.scalac.amqp

testcase用于测试消费消息场景，其代码类似于，运行良好

Source<Object, NotUsed> src = Source.fromPublisher(conn.consume(props.getQueue(), 1, false)).map(msg -> {
    //some transformation to `ByteString` from "`Delivery`" msg
}

有没有办法通过模拟来测试消费代码

Source<Delivery,NotUsed> del;//Creating this object before calling the test

PowerMockito.spy(Source.class);  
PowerMockito.when(Source.fromPublisher(Mockito.isA(Publisher.class))).thenReturn(del);
    //Also tried
//PowerMockito.when(Source.fromPublisher(Mockito.isA(QueuePublisher.class))).thenReturn(del);