tests: Use batched RPC in feature_fee_estimation

feature_fee_estimation has a lot of loops that hit the RPC many times in
succession in order to setup scenarios. Using batched requests for these
can reduce the test's runtime without effecting the test's behavior.

test/functional/feature_fee_estimation.py

@@ -23,7 +23,7 @@ from test_framework.wallet import MiniWallet
 
 
 def small_txpuzzle_randfee(
-    wallet, from_node, conflist, unconflist, amount, min_fee, fee_increment
+    wallet, from_node, conflist, unconflist, amount, min_fee, fee_increment, batch_reqs
 ):
     """Create and send a transaction with a random fee using MiniWallet.
 
@@ -57,8 +57,11 @@ def small_txpuzzle_randfee(
     tx.vout[0].nValue = int((total_in - amount - fee) * COIN)
     tx.vout.append(deepcopy(tx.vout[0]))
     tx.vout[1].nValue = int(amount * COIN)
+    tx.rehash()
+    txid = tx.hash
+    tx_hex = tx.serialize().hex()
 
-    txid = from_node.sendrawtransaction(hexstring=tx.serialize().hex(), maxfeerate=0)
+    batch_reqs.append(from_node.sendrawtransaction.get_request(hexstring=tx_hex, maxfeerate=0))
     unconflist.append({"txid": txid, "vout": 0, "value": total_in - amount - fee})
     unconflist.append({"txid": txid, "vout": 1, "value": amount})
 
@@ -115,13 +118,12 @@ def check_estimates(node, fees_seen):
     check_smart_estimates(node, fees_seen)
 
 
-def send_tx(wallet, node, utxo, feerate):
+def make_tx(wallet, utxo, feerate):
-    """Broadcast a 1in-1out transaction with a specific input and feerate (sat/vb)."""
+    """Create a 1in-1out transaction with a specific input and feerate (sat/vb)."""
-    return wallet.send_self_transfer(
+    return wallet.create_self_transfer(
-        from_node=node,
         utxo_to_spend=utxo,
         fee_rate=Decimal(feerate * 1000) / COIN,
-    )['txid']
+    )
 
 
 class EstimateFeeTest(BitcoinTestFramework):
@@ -156,6 +158,7 @@ class EstimateFeeTest(BitcoinTestFramework):
         # resorting to tx's that depend on the mempool when those run out
         for _ in range(numblocks):
             random.shuffle(self.confutxo)
+            batch_sendtx_reqs = []
             for _ in range(random.randrange(100 - 50, 100 + 50)):
                 from_index = random.randint(1, 2)
                 (tx_bytes, fee) = small_txpuzzle_randfee(
@@ -166,9 +169,12 @@ class EstimateFeeTest(BitcoinTestFramework):
                     Decimal("0.005"),
                     min_fee,
                     min_fee,
+                    batch_sendtx_reqs,
                 )
                 tx_kbytes = tx_bytes / 1000.0
                 self.fees_per_kb.append(float(fee) / tx_kbytes)
+            for node in self.nodes:
+                node.batch(batch_sendtx_reqs)
             self.sync_mempools(wait=0.1)
             mined = mining_node.getblock(self.generate(mining_node, 1)[0], True)["tx"]
             # update which txouts are confirmed
@@ -245,14 +251,20 @@ class EstimateFeeTest(BitcoinTestFramework):
         assert_greater_than_or_equal(len(utxos), 250)
         for _ in range(5):
             # Broadcast 45 low fee transactions that will need to be RBF'd
+            txs = []
             for _ in range(45):
                 u = utxos.pop(0)
-                txid = send_tx(self.wallet, node, u, low_feerate)
+                tx = make_tx(self.wallet, u, low_feerate)
                 utxos_to_respend.append(u)
-                txids_to_replace.append(txid)
+                txids_to_replace.append(tx["txid"])
+                txs.append(tx)
             # Broadcast 5 low fee transaction which don't need to
             for _ in range(5):
-                send_tx(self.wallet, node, utxos.pop(0), low_feerate)
+                tx = make_tx(self.wallet, utxos.pop(0), low_feerate)
+                txs.append(tx)
+            batch_send_tx = [node.sendrawtransaction.get_request(tx["hex"]) for tx in txs]
+            for n in self.nodes:
+                n.batch(batch_send_tx)
             # Mine the transactions on another node
             self.sync_mempools(wait=0.1, nodes=[node, miner])
             for txid in txids_to_replace:
@@ -261,7 +273,12 @@ class EstimateFeeTest(BitcoinTestFramework):
             # RBF the low-fee transactions
             while len(utxos_to_respend) > 0:
                 u = utxos_to_respend.pop(0)
-                send_tx(self.wallet, node, u, high_feerate)
+                tx = make_tx(self.wallet, u, high_feerate)
+                node.sendrawtransaction(tx["hex"])
+                txs.append(tx)
+            dec_txs = [res["result"] for res in node.batch([node.decoderawtransaction.get_request(tx["hex"]) for tx in txs])]
+            self.wallet.scan_txs(dec_txs)
+
 
         # Mine the last replacement txs
         self.sync_mempools(wait=0.1, nodes=[node, miner])

test/functional/test_framework/wallet.py

@@ -141,6 +141,10 @@ class MiniWallet:
             if out['scriptPubKey']['hex'] == self._scriptPubKey.hex():
                 self._utxos.append(self._create_utxo(txid=tx["txid"], vout=out["n"], value=out["value"], height=0))
 
+    def scan_txs(self, txs):
+        for tx in txs:
+            self.scan_tx(tx)
+
     def sign_tx(self, tx, fixed_length=True):
         """Sign tx that has been created by MiniWallet in P2PK mode"""
         assert_equal(self._mode, MiniWalletMode.RAW_P2PK)