chain(fix): conflict resolution for txs with same last_seen

The tx conflict `Scenario` test for unconfirmed txs with the same
last_seen has been amended for its corresponding conflict
resolution bug fix.

crates/chain/src/tx_graph.rs

@@ -789,6 +789,12 @@ impl<A: Anchor> TxGraph<A> {
                 if conflicting_tx.last_seen_unconfirmed > tx_last_seen {
                     return Ok(None);
                 }
+                if conflicting_tx.last_seen_unconfirmed == *last_seen
+                    && conflicting_tx.txid() > tx.txid()
+                {
+                    // Conflicting tx has priority if txid of conflicting tx > txid of original tx
+                    return Ok(None);
+                }
             }
         }
 

crates/chain/tests/test_tx_graph_conflicts.rs

@@ -70,14 +70,12 @@ fn test_tx_conflict_handling() {
                     ..Default::default()
                 },
             ],
-            // correct output if filtered by fee rate: tx1, tx_conflict_1
-            exp_chain_txs: HashSet::from(["tx1", "tx_conflict_1", "tx_conflict_2"]),
-            exp_chain_txouts: HashSet::from([("tx1", 0), ("tx_conflict_1", 0), ("tx_conflict_2", 0)]),
-            // correct output if filtered by fee rate: tx_conflict_1
-            exp_unspents: HashSet::from([("tx_conflict_1", 0), ("tx_conflict_2", 0)]),
+            exp_chain_txs: HashSet::from(["tx1", "tx_conflict_1"]),
+            exp_chain_txouts: HashSet::from([("tx1", 0), ("tx_conflict_1", 0)]),
+            exp_unspents: HashSet::from([("tx_conflict_1", 0)]),
             exp_balance: Balance {
                 immature: 0,
-                trusted_pending: 50000, // correct output if filtered by fee rate: 20000
+                trusted_pending: 20000,
                 untrusted_pending: 0,
                 confirmed: 0,
             },