diff --git a/src/wallet/locked_outpoints.rs b/src/wallet/locked_outpoints.rs
index 6ab2cbc3..dfee71b6 100644
--- a/src/wallet/locked_outpoints.rs
+++ b/src/wallet/locked_outpoints.rs
@@ -24,3 +24,81 @@ impl Merge for ChangeSet {
         self.outpoints.is_empty()
     }
 }
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use bdk_chain::Merge;
+    use bitcoin::{hashes::Hash, OutPoint, Txid};
+
+    /// Helper to create an `OutPoint` from an index byte.
+    fn outpoint(vout: u32) -> OutPoint {
+        OutPoint {
+            txid: Txid::from_byte_array([vout as u8; 32]),
+            vout,
+        }
+    }
+
+    #[test]
+    fn test_is_empty_default() {
+        let cs = ChangeSet::default();
+        assert!(cs.is_empty());
+    }
+
+    #[test]
+    fn test_is_empty_with_entries() {
+        let cs = ChangeSet {
+            outpoints: [(outpoint(0), true)].into(),
+        };
+        assert!(!cs.is_empty());
+    }
+
+    #[test]
+    fn test_merge_into_empty() {
+        let mut cs = ChangeSet::default();
+        let other = ChangeSet {
+            outpoints: [(outpoint(1), true)].into(),
+        };
+        cs.merge(other);
+        assert_eq!(cs.outpoints.len(), 1);
+        assert!(cs.outpoints[&outpoint(1)]);
+    }
+
+    #[test]
+    fn test_merge_empty_into_non_empty() {
+        let mut cs = ChangeSet {
+            outpoints: [(outpoint(0), true)].into(),
+        };
+        let snapshot = cs.clone();
+        cs.merge(ChangeSet::default());
+        assert_eq!(cs, snapshot);
+    }
+
+    #[test]
+    fn test_merge_disjoint() {
+        let mut cs = ChangeSet {
+            outpoints: [(outpoint(0), true)].into(),
+        };
+        let other = ChangeSet {
+            outpoints: [(outpoint(1), false)].into(),
+        };
+        cs.merge(other);
+        assert_eq!(cs.outpoints.len(), 2);
+        assert!(cs.outpoints[&outpoint(0)]);
+        assert!(!cs.outpoints[&outpoint(1)]);
+    }
+
+    #[test]
+    fn test_merge_overwrites_duplicate() {
+        let op = outpoint(0);
+        let mut cs = ChangeSet {
+            outpoints: [(op, true)].into(),
+        };
+        let other = ChangeSet {
+            outpoints: [(op, false)].into(),
+        };
+        cs.merge(other);
+        assert_eq!(cs.outpoints.len(), 1);
+        assert!(!cs.outpoints[&op], "other's value should overwrite self");
+    }
+}