Merge #16535: test: Explain why -whitelist is used in feature_fee_estimation

fa76285fdd test: Explain why -whitelist is used in feature_fee_estimation (MarcoFalke)
faff85a69a test: Format feature_fee_estimation with pep8 (MarcoFalke)

Pull request description:

ACKs for top commit:
  practicalswift:
    ACK fa76285fdd -- diff looks correct
  Sjors:
    ACK fa76285, every bit of clarification helps. It's clear that without `-whitelist` the test becomes extremely slow (it does pass).

Tree-SHA512: 13ec7e4cd0409e7bb76cbcd344e31c0f612c8ce4a1f1ec6ceaedf345f634bc09786ed38d38920c3469b2862c856ee3e5e42534ef90f531bd8dc83c3db3c06417

test/functional/feature_fee_estimation.py

@@ -28,6 +28,7 @@ P2SH_2 = CScript([OP_HASH160, hash160(REDEEM_SCRIPT_2), OP_EQUAL])
 # Associated ScriptSig's to spend satisfy P2SH_1 and P2SH_2
 SCRIPT_SIG = [CScript([OP_TRUE, REDEEM_SCRIPT_1]), CScript([OP_TRUE, REDEEM_SCRIPT_2])]
 
+
 def small_txpuzzle_randfee(from_node, conflist, unconflist, amount, min_fee, fee_increment):
     """Create and send a transaction with a random fee.
 
@@ -69,6 +70,7 @@ def small_txpuzzle_randfee(from_node, conflist, unconflist, amount, min_fee, fee
 
     return (ToHex(tx), fee)
 
+
 def split_inputs(from_node, txins, txouts, initial_split=False):
     """Generate a lot of inputs so we can generate a ton of transactions.
 
@@ -97,6 +99,7 @@ def split_inputs(from_node, txins, txouts, initial_split=False):
     txouts.append({"txid": txid, "vout": 0, "amount": half_change})
     txouts.append({"txid": txid, "vout": 1, "amount": rem_change})
 
+
 def check_estimates(node, fees_seen):
     """Call estimatesmartfee and verify that the estimates meet certain invariants."""
 
@@ -125,10 +128,11 @@ class EstimateFeeTest(BitcoinTestFramework):
     def set_test_params(self):
         self.num_nodes = 3
         # mine non-standard txs (e.g. txs with "dust" outputs)
+        # Force fSendTrickle to true (via whitelist)
         self.extra_args = [
-            ["-acceptnonstdtxn", "-maxorphantx=1000", "-whitelist=127.0.0.1"],
+            ["-acceptnonstdtxn", "-whitelist=127.0.0.1"],
-            ["-acceptnonstdtxn", "-blockmaxweight=68000", "-maxorphantx=1000"],
+            ["-acceptnonstdtxn", "-whitelist=127.0.0.1", "-blockmaxweight=68000"],
-            ["-acceptnonstdtxn", "-blockmaxweight=32000", "-maxorphantx=1000"],
+            ["-acceptnonstdtxn", "-whitelist=127.0.0.1", "-blockmaxweight=32000"],
         ]
 
     def skip_test_if_missing_module(self):
@@ -165,9 +169,9 @@ class EstimateFeeTest(BitcoinTestFramework):
                                                       self.memutxo, Decimal("0.005"), min_fee, min_fee)
                 tx_kbytes = (len(txhex) // 2) / 1000.0
                 self.fees_per_kb.append(float(fee) / tx_kbytes)
-            self.sync_mempools(self.nodes[0:3], wait=.1)
+            self.sync_mempools(wait=.1)
             mined = mining_node.getblock(mining_node.generate(1)[0], True)["tx"]
-            self.sync_blocks(self.nodes[0:3], wait=.1)
+            self.sync_blocks(wait=.1)
             # update which txouts are confirmed
             newmem = []
             for utx in self.memutxo:
@@ -189,22 +193,22 @@ class EstimateFeeTest(BitcoinTestFramework):
         split_inputs(self.nodes[0], self.nodes[0].listunspent(0), self.txouts, True)
 
         # Mine
-        while (len(self.nodes[0].getrawmempool()) > 0):
+        while len(self.nodes[0].getrawmempool()) > 0:
             self.nodes[0].generate(1)
 
         # Repeatedly split those 2 outputs, doubling twice for each rep
         # Use txouts to monitor the available utxo, since these won't be tracked in wallet
         reps = 0
-        while (reps < 5):
+        while reps < 5:
             # Double txouts to txouts2
-            while (len(self.txouts) > 0):
+            while len(self.txouts) > 0:
                 split_inputs(self.nodes[0], self.txouts, self.txouts2)
-            while (len(self.nodes[0].getrawmempool()) > 0):
+            while len(self.nodes[0].getrawmempool()) > 0:
                 self.nodes[0].generate(1)
             # Double txouts2 to txouts
-            while (len(self.txouts2) > 0):
+            while len(self.txouts2) > 0:
                 split_inputs(self.nodes[0], self.txouts2, self.txouts)
-            while (len(self.nodes[0].getrawmempool()) > 0):
+            while len(self.nodes[0].getrawmempool()) > 0:
                 self.nodes[0].generate(1)
             reps += 1
         self.log.info("Finished splitting")
@@ -244,5 +248,6 @@ class EstimateFeeTest(BitcoinTestFramework):
         self.log.info("Final estimates after emptying mempools")
         check_estimates(self.nodes[1], self.fees_per_kb)
 
+
 if __name__ == '__main__':
     EstimateFeeTest().main()

test/functional/test_runner.py

@@ -76,7 +76,6 @@ EXTENDED_SCRIPTS = [
 BASE_SCRIPTS = [
     # Scripts that are run by default.
     # Longest test should go first, to favor running tests in parallel
-    'feature_fee_estimation.py',
     'wallet_hd.py',
     'wallet_backup.py',
     # vv Tests less than 5m vv
@@ -111,6 +110,7 @@ BASE_SCRIPTS = [
     'feature_abortnode.py',
     # vv Tests less than 30s vv
     'wallet_keypool_topup.py',
+    'feature_fee_estimation.py',
     'interface_zmq.py',
     'interface_bitcoin_cli.py',
     'mempool_resurrect.py',