if you let AI add Deserialize for everything Serialize you will have to fight this

Co-authored-by: Copilot <[email protected]>

wakey-core/src/model/neighbor.rs

@@ -12,7 +12,7 @@ use crate::parse::mac;
 pub struct NeighborEntry {
     pub ip: IpAddr,
     pub dev: Option<String>,
-    #[serde(with = "mac::option_mac")]
+    #[serde(with = "mac::option_mac", default)]
     pub mac: Option<MacAddr>,
     pub state: NeighborState,
 }
@@ -132,3 +132,27 @@ impl FromStr for NeighborEntry {
         parse_neighbor_line(s)
     }
 }
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    #[test]
+    fn deserialize_online_neighbor() {
+        NeighborEntry::deserialize(serde_json::json!({
+            "ip" : "192.168.100.94",
+            "dev" : "br-lan",
+            "mac" : "04:7C:16:79:6D:EE",
+            "state" : "REACHABLE"
+        }))
+        .expect("all fields must pass");
+    }
+    #[test]
+    fn deserialize_failed_neighbor() {
+        NeighborEntry::deserialize(serde_json::json!({
+            "ip" : "192.168.100.94",
+            "dev" : "br-lan",
+            "state" : "FAILED"
+        }))
+        .expect("default");
+    }
+}