wollet: another test for Update v4 last update

Author: RCasatta

lwk_wollet/src/update.rs

@@ -1201,6 +1201,54 @@ mod test {
         assert_eq!(update.last_unused.internal, 8);
     }
 
+    #[test]
+    fn test_apply_v4_update_fetch_max_semantics() {
+        let desc: WolletDescriptor = lwk_test_util::wollet_descriptor_string().parse().unwrap();
+        let network = Network::default_regtest();
+        let mut wollet = WolletBuilder::new(network, desc).build().unwrap();
+
+        wollet
+            .apply_update(Update {
+                version: 4,
+                wollet_status: wollet.status(),
+                new_txs: DownloadTxResult::default(),
+                txid_height_new: vec![],
+                txid_height_delete: vec![],
+                timestamps: vec![],
+                scripts_with_blinding_pubkey: vec![],
+                tip: super::default_blockheader(),
+                unspent: vec![],
+                last_unused: LastUnused {
+                    external: 7,
+                    internal: 11,
+                },
+            })
+            .unwrap();
+
+        assert_eq!(wollet.address(None).unwrap().index(), 7);
+
+        wollet
+            .apply_update(Update {
+                version: 4,
+                wollet_status: wollet.status(),
+                new_txs: DownloadTxResult::default(),
+                txid_height_new: vec![],
+                txid_height_delete: vec![],
+                timestamps: vec![],
+                scripts_with_blinding_pubkey: vec![],
+                tip: super::default_blockheader(),
+                unspent: vec![],
+                last_unused: LastUnused {
+                    external: 3,
+                    internal: 5,
+                },
+            })
+            .unwrap();
+
+        assert_eq!(wollet.address(None).unwrap().index(), 7);
+        assert_eq!(wollet.change(None).unwrap().index(), 11);
+    }
+
     #[test]
     fn test_update_decription() {
         let update = Update::deserialize(&lwk_test_util::update_test_vector_bytes()).unwrap();