@Test
public void testEnsureOpen() throws InterruptedException {

    EmbeddedChannel channel = new EmbeddedChannel();
    channel.close().syncUninterruptibly();
    try {
        channel.writeOutbound("Hello, Netty!");
        fail("This should have failed with a ClosedChannelException");
    } catch (Exception expected) {
        assertTrue(expected instanceof ClosedChannelException);
    }
    try {
        channel.writeInbound("Hello, Netty!");
        fail("This should have failed with a ClosedChannelException");
    } catch (Exception expected) {
        assertTrue(expected instanceof ClosedChannelException);
    }
}