### Question:
ChannelOutboundQueue extends ChannelInboundHandlerAdapter { public boolean enqueue(final MessageHolder<?> holder) { LOG.trace("Enqueuing message {}", holder); if (queue.offer(holder)) { LOG.trace("Message enqueued"); conditionalFlush(); return true; } LOG.debug("Message queue is full"); return false; } ChannelOutboundQueue(final Channel channel, final int queueDepth, final InetSocketAddress address); boolean enqueue(final MessageHolder<?> holder); @Override void channelActive(final ChannelHandlerContext ctx); @Override void channelWritabilityChanged(final ChannelHandlerContext ctx); @Override void channelInactive(final ChannelHandlerContext ctx); @Override String toString();  }### Answer:
@Test public void testEnqueue() { ChannelOutboundQueue queue = new ChannelOutboundQueue(channel, 1, null); boolean enqueued; enqueued = queue.enqueue(new SimpleRpcListener("INPUT", "Failed to send INPUT")); Assert.assertTrue("Enqueue problem", enqueued); enqueued = queue.enqueue(new SimpleRpcListener("INPUT", "Failed to send INPUT")); Assert.assertFalse("Enqueue problem", enqueued); }