@Test
  public void failedConnectionAcquireNotifiesPromise() throws InterruptedException {
    IOException exception = new IOException();
    ChannelPool connectionPool = mock(ChannelPool.class);
    when(connectionPool.acquire()).thenReturn(new FailedFuture<>(loopGroup.next(), exception));

    ChannelPool pool = new Http2MultiplexedChannelPool(connectionPool, loopGroup.next(), new HashSet<>(), null,
        http2ClientConfigForOneConnection, new Http2ClientMetrics(new MetricRegistry()), streamChannelInitializer);

    Future<Channel> acquirePromise = pool.acquire().await();
    assertFalse(acquirePromise.isSuccess());
    assertEquals(acquirePromise.cause(), exception);
  }
Channel acquire should fail if parent channel pool acquire fails.
ambry-network/src/test/java/com/github/ambry/network/http2/Http2MultiplexedChannelPoolTest.java