diff --git a/satrs-example/src/acs/mgm.rs b/satrs-example/src/acs/mgm.rs
index 1b0f3b5..b102225 100644
--- a/satrs-example/src/acs/mgm.rs
+++ b/satrs-example/src/acs/mgm.rs
@@ -532,7 +532,7 @@ mod tests {
                 hk_reply_rx,
                 handler: MgmHandlerLis3Mdl::new(
                     UniqueApidTargetId::new(Apid::Acs as u16, 1),
-                    "test-mgm",
+                    "TEST_MGM",
                     mode_interface,
                     composite_request_rx,
                     hk_reply_tx,
diff --git a/satrs-example/src/eps/pcdu.rs b/satrs-example/src/eps/pcdu.rs
index d51ca55..875b398 100644
--- a/satrs-example/src/eps/pcdu.rs
+++ b/satrs-example/src/eps/pcdu.rs
@@ -130,15 +130,13 @@ impl SerialInterface for SerialInterfaceDummy {
         &self,
         mut f: ReplyHandler,
     ) -> Result<(), Self::Error> {
-        if self.reply_deque.borrow().is_empty() {
+        if self.reply_queue_empty() {
             return Ok(());
         }
         loop {
-            let mut reply_deque_mut = self.reply_deque.borrow_mut();
-            let next_reply = reply_deque_mut.pop_front().unwrap();
-            let reply = serde_json::to_string(&next_reply).unwrap();
+            let reply = self.get_next_reply_as_string();
             f(reply.as_bytes());
-            if reply_deque_mut.is_empty() {
+            if self.reply_queue_empty() {
                 break;
             }
         }
@@ -146,6 +144,18 @@ impl SerialInterface for SerialInterfaceDummy {
     }
 }
 
+impl SerialInterfaceDummy {
+    fn get_next_reply_as_string(&self) -> String {
+        let mut reply_deque_mut = self.reply_deque.borrow_mut();
+        let next_reply = reply_deque_mut.pop_front().unwrap();
+        serde_json::to_string(&next_reply).unwrap()
+    }
+
+    fn reply_queue_empty(&self) -> bool {
+        self.reply_deque.borrow().is_empty()
+    }
+}
+
 pub enum SerialSimInterfaceWrapper {
     Dummy(SerialInterfaceDummy),
     Sim(SerialInterfaceToSim),
@@ -465,3 +475,127 @@ impl<ComInterface: SerialInterface, TmSender: EcssTmSender> ModeRequestHandler
         Ok(())
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use std::sync::mpsc;
+
+    use satrs::{mode::ModeRequest, request::GenericMessage, tmtc::PacketAsVec};
+    use satrs_example::config::components::Apid;
+
+    use super::*;
+
+    #[derive(Default)]
+    pub struct SerialInterfaceTest {
+        pub inner: SerialInterfaceDummy,
+        pub send_queue: RefCell<VecDeque<Vec<u8>>>,
+        pub reply_queue: RefCell<VecDeque<String>>,
+    }
+
+    impl SerialInterface for SerialInterfaceTest {
+        type Error = ();
+
+        fn send(&self, data: &[u8]) -> Result<(), Self::Error> {
+            let mut send_queue_mut = self.send_queue.borrow_mut();
+            send_queue_mut.push_back(data.to_vec());
+            self.inner.send(data)
+        }
+
+        fn try_recv_replies<ReplyHandler: FnMut(&[u8])>(
+            &self,
+            mut f: ReplyHandler,
+        ) -> Result<(), Self::Error> {
+            if self.inner.reply_queue_empty() {
+                return Ok(());
+            }
+            loop {
+                let reply = self.inner.get_next_reply_as_string();
+                self.reply_queue.borrow_mut().push_back(reply.clone());
+                f(reply.as_bytes());
+                if self.inner.reply_queue_empty() {
+                    break;
+                }
+            }
+            Ok(())
+        }
+    }
+
+    pub struct PcduTestbench {
+        pub mode_request_tx: mpsc::Sender<GenericMessage<ModeRequest>>,
+        pub mode_reply_rx_to_pus: mpsc::Receiver<GenericMessage<ModeReply>>,
+        pub mode_reply_rx_to_parent: mpsc::Receiver<GenericMessage<ModeReply>>,
+        pub composite_request_tx: mpsc::Sender<GenericMessage<CompositeRequest>>,
+        pub hk_reply_rx: mpsc::Receiver<GenericMessage<HkReply>>,
+        pub tm_rx: mpsc::Receiver<PacketAsVec>,
+        pub switch_request_tx: mpsc::Sender<GenericMessage<SwitchRequest>>,
+        pub handler: PcduHandler<SerialInterfaceTest, mpsc::Sender<PacketAsVec>>,
+    }
+
+    impl PcduTestbench {
+        pub fn new() -> Self {
+            let (mode_request_tx, mode_request_rx) = mpsc::channel();
+            let (mode_reply_tx_to_pus, mode_reply_rx_to_pus) = mpsc::channel();
+            let (mode_reply_tx_to_parent, mode_reply_rx_to_parent) = mpsc::sync_channel(5);
+            let mode_interface = MpscModeLeafInterface {
+                request_rx: mode_request_rx,
+                reply_to_pus_tx: mode_reply_tx_to_pus,
+                reply_to_parent_tx: mode_reply_tx_to_parent,
+            };
+            let (composite_request_tx, composite_request_rx) = mpsc::channel();
+            let (hk_reply_tx, hk_reply_rx) = mpsc::channel();
+            let (tm_tx, tm_rx) = mpsc::channel::<PacketAsVec>();
+            let (switch_request_tx, switch_reqest_rx) = mpsc::channel();
+            let shared_switch_map = Arc::new(Mutex::new(SwitchSet::default()));
+            Self {
+                mode_request_tx,
+                mode_reply_rx_to_pus,
+                mode_reply_rx_to_parent,
+                composite_request_tx,
+                hk_reply_rx,
+                tm_rx,
+                switch_request_tx,
+                handler: PcduHandler::new(
+                    UniqueApidTargetId::new(Apid::Eps as u16, 0),
+                    "TEST_PCDU",
+                    mode_interface,
+                    composite_request_rx,
+                    hk_reply_tx,
+                    switch_reqest_rx,
+                    tm_tx,
+                    SerialInterfaceTest::default(),
+                    shared_switch_map,
+                ),
+            }
+        }
+    }
+
+    #[test]
+    fn test_basic_handler() {
+        let mut testbench = PcduTestbench::new();
+        assert_eq!(testbench.handler.com_interface.send_queue.borrow().len(), 0);
+        assert_eq!(
+            testbench.handler.com_interface.reply_queue.borrow().len(),
+            0
+        );
+        assert_eq!(
+            testbench.handler.mode_and_submode().mode(),
+            DeviceMode::Off as u32
+        );
+        assert_eq!(testbench.handler.mode_and_submode().submode(), 0_u16);
+        testbench.handler.periodic_operation(OpCode::RegularOp);
+        testbench
+            .handler
+            .periodic_operation(OpCode::PollAndRecvReplies);
+        // Handler is OFF, no changes expected.
+        assert_eq!(testbench.handler.com_interface.send_queue.borrow().len(), 0);
+        assert_eq!(
+            testbench.handler.com_interface.reply_queue.borrow().len(),
+            0
+        );
+        assert_eq!(
+            testbench.handler.mode_and_submode().mode(),
+            DeviceMode::Off as u32
+        );
+        assert_eq!(testbench.handler.mode_and_submode().submode(), 0_u16);
+    }
+}