diff --git a/rocketmq-client/src/consumer/consumer_impl/pop_process_queue.rs b/rocketmq-client/src/consumer/consumer_impl/pop_process_queue.rs
index 99be2a0d..7a04df9c 100644
--- a/rocketmq-client/src/consumer/consumer_impl/pop_process_queue.rs
+++ b/rocketmq-client/src/consumer/consumer_impl/pop_process_queue.rs
@@ -1,85 +1,168 @@
-/*
- * 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.
- */
-use std::sync::atomic::AtomicUsize;
-use std::sync::atomic::Ordering;
-use std::sync::Arc;
-
-use rocketmq_common::TimeUtils::get_current_millis;
-use rocketmq_remoting::protocol::body::pop_process_queue_info::PopProcessQueueInfo;
-
-use crate::consumer::consumer_impl::PULL_MAX_IDLE_TIME;
-
-#[derive(Clone)]
-pub(crate) struct PopProcessQueue {
-    last_pop_timestamp: u64,
-    wait_ack_counter: Arc<AtomicUsize>,
-    dropped: bool,
-}
-
-impl PopProcessQueue {
-    pub(crate) fn new() -> Self {
-        PopProcessQueue {
-            last_pop_timestamp: get_current_millis(),
-            wait_ack_counter: Arc::new(AtomicUsize::new(0)),
-            dropped: false,
-        }
-    }
-
-    pub(crate) fn get_last_pop_timestamp(&self) -> u64 {
-        self.last_pop_timestamp
-    }
-
-    pub(crate) fn set_last_pop_timestamp(&mut self, last_pop_timestamp: u64) {
-        self.last_pop_timestamp = last_pop_timestamp;
-    }
-
-    pub(crate) fn inc_found_msg(&self, count: isize) {
-        self.wait_ack_counter
-            .fetch_add(count as usize, Ordering::Relaxed);
-    }
-
-    pub(crate) fn ack(&self) -> usize {
-        self.wait_ack_counter.fetch_sub(1, Ordering::Relaxed)
-    }
-    pub(crate) fn dec_found_msg(&self, count: isize) {
-        self.wait_ack_counter
-            .fetch_add(-count as usize, Ordering::Relaxed);
-    }
-
-    pub(crate) fn get_wai_ack_msg_count(&self) -> usize {
-        self.wait_ack_counter.load(Ordering::Relaxed)
-    }
-
-    pub(crate) fn is_dropped(&self) -> bool {
-        self.dropped
-    }
-
-    pub(crate) fn set_dropped(&self, dropped: bool) {
-        //self.dropped = dropped;
-    }
-
-    pub(crate) fn fill_pop_process_queue_info(&self, info: &mut PopProcessQueueInfo) {
-        info.set_wait_ack_count(self.get_wai_ack_msg_count() as i32);
-        info.set_droped(self.is_dropped());
-        info.set_last_pop_timestamp(self.get_last_pop_timestamp());
-    }
-
-    pub(crate) fn is_pull_expired(&self) -> bool {
-        let current_time = get_current_millis();
-        (current_time - self.last_pop_timestamp) > *PULL_MAX_IDLE_TIME
-    }
-}
+/*
+ * 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.
+ */
+use std::fmt::Display;
+use std::sync::atomic::AtomicBool;
+use std::sync::atomic::AtomicUsize;
+use std::sync::atomic::Ordering;
+use std::sync::Arc;
+
+use rocketmq_common::TimeUtils::get_current_millis;
+use rocketmq_remoting::protocol::body::pop_process_queue_info::PopProcessQueueInfo;
+
+use crate::consumer::consumer_impl::PULL_MAX_IDLE_TIME;
+
+#[derive(Clone)]
+pub(crate) struct PopProcessQueue {
+    last_pop_timestamp: u64,
+    wait_ack_counter: Arc<AtomicUsize>,
+    dropped: Arc<AtomicBool>,
+}
+
+impl Default for PopProcessQueue {
+    fn default() -> Self {
+        PopProcessQueue {
+            last_pop_timestamp: get_current_millis(),
+            wait_ack_counter: Arc::new(AtomicUsize::new(0)),
+            dropped: Arc::new(AtomicBool::new(false)),
+        }
+    }
+}
+
+impl PopProcessQueue {
+    pub(crate) fn new() -> Self {
+        PopProcessQueue {
+            last_pop_timestamp: get_current_millis(),
+            wait_ack_counter: Arc::new(AtomicUsize::new(0)),
+            dropped: Arc::new(AtomicBool::new(false)),
+        }
+    }
+
+    pub(crate) fn get_last_pop_timestamp(&self) -> u64 {
+        self.last_pop_timestamp
+    }
+
+    pub(crate) fn set_last_pop_timestamp(&mut self, last_pop_timestamp: u64) {
+        self.last_pop_timestamp = last_pop_timestamp;
+    }
+
+    pub(crate) fn inc_found_msg(&self, count: isize) {
+        self.wait_ack_counter
+            .fetch_add(count as usize, Ordering::Relaxed);
+    }
+
+    pub(crate) fn ack(&self) -> usize {
+        self.wait_ack_counter.fetch_sub(1, Ordering::Relaxed)
+    }
+    pub(crate) fn dec_found_msg(&self, count: isize) {
+        self.wait_ack_counter
+            .fetch_add(-count as usize, Ordering::Relaxed);
+    }
+
+    pub(crate) fn get_wai_ack_msg_count(&self) -> usize {
+        self.wait_ack_counter.load(Ordering::Relaxed)
+    }
+
+    pub(crate) fn is_dropped(&self) -> bool {
+        self.dropped.load(Ordering::Relaxed)
+    }
+
+    pub(crate) fn set_dropped(&self, dropped: bool) {
+        self.dropped.store(dropped, Ordering::Relaxed);
+    }
+
+    pub(crate) fn fill_pop_process_queue_info(&self, info: &mut PopProcessQueueInfo) {
+        info.set_wait_ack_count(self.get_wai_ack_msg_count() as i32);
+        info.set_droped(self.is_dropped());
+        info.set_last_pop_timestamp(self.get_last_pop_timestamp());
+    }
+
+    pub(crate) fn is_pull_expired(&self) -> bool {
+        let current_time = get_current_millis();
+        current_time.saturating_sub(self.last_pop_timestamp) > *PULL_MAX_IDLE_TIME
+    }
+}
+
+impl Display for PopProcessQueue {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(
+            f,
+            "PopProcessQueue [last_pop_timestamp={}, wait_ack_counter={}, dropped={}]",
+            self.last_pop_timestamp,
+            self.wait_ack_counter.load(Ordering::Relaxed),
+            self.dropped.load(Ordering::Relaxed)
+        )
+    }
+}
+
+#[cfg(test)]
+mod tests {
+
+    use super::*;
+
+    #[test]
+    fn pop_process_queue_initializes_correctly() {
+        let queue = PopProcessQueue::new();
+        assert!(queue.get_last_pop_timestamp() > 0);
+        assert_eq!(queue.get_wai_ack_msg_count(), 0);
+        assert!(!queue.is_dropped());
+    }
+
+    #[test]
+    fn pop_process_queue_updates_last_pop_timestamp() {
+        let mut queue = PopProcessQueue::new();
+        let new_timestamp = queue.get_last_pop_timestamp() + 1000;
+        queue.set_last_pop_timestamp(new_timestamp);
+        assert_eq!(queue.get_last_pop_timestamp(), new_timestamp);
+    }
+
+    #[test]
+    fn pop_process_queue_increments_found_msg() {
+        let queue = PopProcessQueue::new();
+        queue.inc_found_msg(5);
+        assert_eq!(queue.get_wai_ack_msg_count(), 5);
+    }
+
+    #[test]
+    fn pop_process_queue_decrements_found_msg() {
+        let queue = PopProcessQueue::new();
+        queue.inc_found_msg(5);
+        queue.dec_found_msg(3);
+        assert_eq!(queue.get_wai_ack_msg_count(), 2);
+    }
+
+    #[test]
+    fn pop_process_queue_acknowledges_msg() {
+        let queue = PopProcessQueue::new();
+        queue.inc_found_msg(5);
+        queue.ack();
+        assert_eq!(queue.get_wai_ack_msg_count(), 4);
+    }
+
+    #[test]
+    fn pop_process_queue_sets_dropped_flag() {
+        let queue = PopProcessQueue::new();
+        queue.set_dropped(true);
+        assert!(queue.is_dropped());
+    }
+
+    #[test]
+    fn pop_process_queue_detects_pull_expired() {
+        let mut queue = PopProcessQueue::new();
+        queue.set_last_pop_timestamp(queue.get_last_pop_timestamp() - *PULL_MAX_IDLE_TIME - 1);
+        assert!(queue.is_pull_expired());
+    }
+}