diff --git a/client/src/test/java/org/apache/rocketmq/client/impl/mqclient/MQClientAPIExtTest.java b/client/src/test/java/org/apache/rocketmq/client/impl/mqclient/MQClientAPIExtTest.java
new file mode 100644
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+++ b/client/src/test/java/org/apache/rocketmq/client/impl/mqclient/MQClientAPIExtTest.java
@@ -0,0 +1,74 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.rocketmq.client.impl.mqclient;
+
+import java.util.concurrent.CompletableFuture;
+import org.apache.rocketmq.client.ClientConfig;
+import org.apache.rocketmq.client.producer.SendResult;
+import org.apache.rocketmq.common.message.Message;
+import org.apache.rocketmq.common.utils.FutureUtils;
+import org.apache.rocketmq.remoting.exception.RemotingTimeoutException;
+import org.apache.rocketmq.remoting.netty.NettyClientConfig;
+import org.apache.rocketmq.remoting.netty.NettyRemotingClient;
+import org.apache.rocketmq.remoting.protocol.header.SendMessageRequestHeader;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.junit.MockitoJUnitRunner;
+
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyLong;
+import static org.mockito.ArgumentMatchers.anyString;
+
+@RunWith(MockitoJUnitRunner.class)
+public class MQClientAPIExtTest {
+    MQClientAPIExt mqClientAPIExt;
+    @Mock
+    NettyRemotingClient remotingClientMock;
+
+    @Before
+    public void before() {
+        mqClientAPIExt = Mockito.spy(new MQClientAPIExt(new ClientConfig(), new NettyClientConfig(), null, null));
+        Mockito.when(mqClientAPIExt.getRemotingClient()).thenReturn(remotingClientMock);
+        Mockito.when(remotingClientMock.invoke(anyString(), any(), anyLong())).thenReturn(FutureUtils.completeExceptionally(new RemotingTimeoutException("addr")));
+    }
+
+    @Test
+    public void sendMessageAsync() {
+        String topic = "test";
+        Message msg = new Message(topic, "test".getBytes());
+        SendMessageRequestHeader requestHeader = new SendMessageRequestHeader();
+        requestHeader.setTopic(topic);
+        requestHeader.setProducerGroup("test");
+        requestHeader.setDefaultTopic("test");
+        requestHeader.setDefaultTopicQueueNums(1);
+        requestHeader.setQueueId(0);
+        requestHeader.setSysFlag(0);
+        requestHeader.setBornTimestamp(0L);
+        requestHeader.setFlag(0);
+        requestHeader.setProperties("test");
+        requestHeader.setReconsumeTimes(0);
+        requestHeader.setUnitMode(false);
+        requestHeader.setBatch(false);
+        CompletableFuture<SendResult> future = mqClientAPIExt.sendMessageAsync("127.0.0.1:10911", "test", msg, requestHeader, 10);
+        assertThatThrownBy(future::get).getCause().isInstanceOf(RemotingTimeoutException.class);
+    }
+}
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