### Question:
DssWebSocketHandler extends ChannelInboundHandlerAdapter { @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) { logger.error("exceptionCaught", cause); ctx.close(); }  @Override void channelRead(ChannelHandlerContext ctx, Object msg); @Override void channelReadComplete(ChannelHandlerContext ctx); @Override void exceptionCaught(ChannelHandlerContext ctx, Throwable cause);  }### Answer:
@Test void exceptionCaught() { mockChannelHandlerContextChannelId(ctx, "abcedf"); final DssWebSocketHandler handler = new DssWebSocketHandler(); handler.exceptionCaught(ctx, new NullPointerException()); assertTrue(true); }