[tests] don't override __init__() in individual tests

Almost all test scripts currently need to override the __init__()
method. When they do that they need to call into super().__init__() as
the base class does some generic initialization.

This commit makes the base class __init__() call into set_test_params()
method. Individual test cases can override set_test_params() to setup
their test parameters.

Github-Pull: #11121
Rebased-From: 5448a1471d6fc638a2220ea5a2f3782172efe14c

82 files changed, 145 insertions, 322 deletions

diff --git a/test/functional/README.md b/test/functional/README.md
index 44efda33d3..2558bd017d 100644
--- a/test/functional/README.md
+++ b/test/functional/README.md
@@ -24,8 +24,8 @@ don't have test cases for.
 - Use a module-level docstring to describe what the test is testing, and how it
   is testing it.
 - When subclassing the BitcoinTestFramwork, place overrides for the
-  `__init__()`, and `setup_xxxx()` methods at the top of the subclass, then
-  locally-defined helper methods, then the `run_test()` method.
+  `set_test_params()`, `add_options()` and `setup_xxxx()` methods at the top of
+  the subclass, then locally-defined helper methods, then the `run_test()` method.
 
 #### General test-writing advice
 
@@ -36,7 +36,7 @@ don't have test cases for.
 - Avoid stop-starting the nodes multiple times during the test if possible. A
   stop-start takes several seconds, so doing it several times blows up the
   runtime of the test.
-- Set the `self.setup_clean_chain` variable in `__init__()` to control whether
+- Set the `self.setup_clean_chain` variable in `set_test_params()` to control whether
   or not to use the cached data directories. The cached data directories
   contain a 200-block pre-mined blockchain and wallets for four nodes. Each node
   has 25 mature blocks (25x50=1250 BTC) in its wallet.
diff --git a/test/functional/abandonconflict.py b/test/functional/abandonconflict.py
index 1db04337a9..e8dbc86469 100755
--- a/test/functional/abandonconflict.py
+++ b/test/functional/abandonconflict.py
@@ -14,10 +14,8 @@ from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
 
 class AbandonConflictTest(BitcoinTestFramework):
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.num_nodes = 2
-        self.setup_clean_chain = False
         self.extra_args = [["-minrelaytxfee=0.00001"], []]
 
     def run_test(self):
diff --git a/test/functional/assumevalid.py b/test/functional/assumevalid.py
index ec485281d4..beaf8c7055 100755
--- a/test/functional/assumevalid.py
+++ b/test/functional/assumevalid.py
@@ -54,8 +54,7 @@ class BaseNode(NodeConnCB):
         self.send_message(headers_message)
 
 class AssumeValidTest(BitcoinTestFramework):
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 3
 
diff --git a/test/functional/bip65-cltv-p2p.py b/test/functional/bip65-cltv-p2p.py
index 65ae8de554..2cd6df6e37 100755
--- a/test/functional/bip65-cltv-p2p.py
+++ b/test/functional/bip65-cltv-p2p.py
@@ -60,9 +60,7 @@ def create_transaction(node, coinbase, to_address, amount):
     return tx
 
 class BIP65Test(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.num_nodes = 1
         self.extra_args = [['-promiscuousmempoolflags=1', '-whitelist=127.0.0.1']]
         self.setup_clean_chain = True
diff --git a/test/functional/bip68-112-113-p2p.py b/test/functional/bip68-112-113-p2p.py
index 5a322e8c0e..7e6a4f4408 100755
--- a/test/functional/bip68-112-113-p2p.py
+++ b/test/functional/bip68-112-113-p2p.py
@@ -92,9 +92,9 @@ def all_rlt_txs(txarray):
     return txs
 
 class BIP68_112_113Test(ComparisonTestFramework):
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.num_nodes = 1
+        self.setup_clean_chain = True
         self.extra_args = [['-whitelist=127.0.0.1', '-blockversion=4']]
 
     def run_test(self):
diff --git a/test/functional/bip68-sequence.py b/test/functional/bip68-sequence.py
index 87a50692f6..39012adf95 100755
--- a/test/functional/bip68-sequence.py
+++ b/test/functional/bip68-sequence.py
@@ -17,10 +17,8 @@ SEQUENCE_LOCKTIME_MASK = 0x0000ffff
 NOT_FINAL_ERROR = "64: non-BIP68-final"
 
 class BIP68Test(BitcoinTestFramework):
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.num_nodes = 2
-        self.setup_clean_chain = False
         self.extra_args = [[], ["-acceptnonstdtxn=0"]]
 
     def run_test(self):
diff --git a/test/functional/bip9-softforks.py b/test/functional/bip9-softforks.py
index ad16482550..904789301a 100755
--- a/test/functional/bip9-softforks.py
+++ b/test/functional/bip9-softforks.py
@@ -28,11 +28,10 @@ from test_framework.comptool import TestInstance, TestManager
 from test_framework.script import CScript, OP_1NEGATE, OP_CHECKSEQUENCEVERIFY, OP_DROP
 
 class BIP9SoftForksTest(ComparisonTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.num_nodes = 1
         self.extra_args = [['-whitelist=127.0.0.1']]
+        self.setup_clean_chain = True
 
     def run_test(self):
         self.test = TestManager(self, self.options.tmpdir)
diff --git a/test/functional/bipdersig-p2p.py b/test/functional/bipdersig-p2p.py
index 9775970893..c620d3e155 100755
--- a/test/functional/bipdersig-p2p.py
+++ b/test/functional/bipdersig-p2p.py
@@ -48,9 +48,7 @@ def create_transaction(node, coinbase, to_address, amount):
     return tx
 
 class BIP66Test(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.num_nodes = 1
         self.extra_args = [['-promiscuousmempoolflags=1', '-whitelist=127.0.0.1']]
         self.setup_clean_chain = True
diff --git a/test/functional/blockchain.py b/test/functional/blockchain.py
index a3a6cf2fb8..5d04de9940 100755
--- a/test/functional/blockchain.py
+++ b/test/functional/blockchain.py
@@ -30,12 +30,8 @@ from test_framework.util import (
     assert_is_hash_string,
 )
 
-
 class BlockchainTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
-        self.setup_clean_chain = False
+    def set_test_params(self):
         self.num_nodes = 1
         self.extra_args = [['-stopatheight=207']]
 
diff --git a/test/functional/bumpfee.py b/test/functional/bumpfee.py
index 59c65f18e8..ede0df29d8 100755
--- a/test/functional/bumpfee.py
+++ b/test/functional/bumpfee.py
@@ -30,8 +30,7 @@ WALLET_PASSPHRASE_TIMEOUT = 3600
 
 
 class BumpFeeTest(BitcoinTestFramework):
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.num_nodes = 2
         self.setup_clean_chain = True
         self.extra_args = [["-prematurewitness", "-walletprematurewitness", "-walletrbf={}".format(i)]
diff --git a/test/functional/create_cache.py b/test/functional/create_cache.py
index 1a5754b3f7..7d4d1a529b 100755
--- a/test/functional/create_cache.py
+++ b/test/functional/create_cache.py
@@ -12,11 +12,9 @@ tests are being run in parallel.
 from test_framework.test_framework import BitcoinTestFramework
 
 class CreateCache(BitcoinTestFramework):
+    # Test network and test nodes are not required:
 
-    def __init__(self):
-        super().__init__()
-
-        # Test network and test nodes are not required:
+    def set_test_params(self):
         self.num_nodes = 0
 
     def setup_network(self):
diff --git a/test/functional/dbcrash.py b/test/functional/dbcrash.py
index b0c6d39c49..71424f641b 100755
--- a/test/functional/dbcrash.py
+++ b/test/functional/dbcrash.py
@@ -43,8 +43,7 @@ except AttributeError:
     pass
 
 class ChainstateWriteCrashTest(BitcoinTestFramework):
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.num_nodes = 4
         self.setup_clean_chain = False
 
diff --git a/test/functional/decodescript.py b/test/functional/decodescript.py
index 21a9f1223f..6611da8831 100755
--- a/test/functional/decodescript.py
+++ b/test/functional/decodescript.py
@@ -10,9 +10,7 @@ from test_framework.mininode import *
 from io import BytesIO
 
 class DecodeScriptTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 1
 
diff --git a/test/functional/disablewallet.py b/test/functional/disablewallet.py
index d344513414..c1d37963bc 100755
--- a/test/functional/disablewallet.py
+++ b/test/functional/disablewallet.py
@@ -11,11 +11,8 @@
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
 
-
 class DisableWalletTest (BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 1
         self.extra_args = [["-disablewallet"]]
diff --git a/test/functional/disconnect_ban.py b/test/functional/disconnect_ban.py
index cc8901c40c..a6445b9b35 100755
--- a/test/functional/disconnect_ban.py
+++ b/test/functional/disconnect_ban.py
@@ -14,11 +14,8 @@ from test_framework.util import (
 )
 
 class DisconnectBanTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.num_nodes = 2
-        self.setup_clean_chain = False
 
     def run_test(self):
         self.log.info("Test setban and listbanned RPCs")
diff --git a/test/functional/example_test.py b/test/functional/example_test.py
index a54b5278e4..de8934f74b 100755
--- a/test/functional/example_test.py
+++ b/test/functional/example_test.py
@@ -73,15 +73,11 @@ def custom_function():
 class ExampleTest(BitcoinTestFramework):
     # Each functional test is a subclass of the BitcoinTestFramework class.
 
-    # Override the __init__(), add_options(), setup_chain(), setup_network()
+    # Override the set_test_params(), add_options(), setup_chain(), setup_network()
     # and setup_nodes() methods to customize the test setup as required.
 
-    def __init__(self):
-        """Initialize the test
-
-        Call super().__init__() first, and then override any test parameters
-        for your individual test."""
-        super().__init__()
+    def set_test_params(self):
+        """Override any test parameters for your individual test."""
         self.setup_clean_chain = True
         self.num_nodes = 3
         # Use self.extra_args to change command-line arguments for the nodes
diff --git a/test/functional/forknotify.py b/test/functional/forknotify.py
index 3a2a927098..afcad1f9cc 100755
--- a/test/functional/forknotify.py
+++ b/test/functional/forknotify.py
@@ -9,11 +9,8 @@ import time
 from test_framework.test_framework import BitcoinTestFramework
 
 class ForkNotifyTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.num_nodes = 2
-        self.setup_clean_chain = False
 
     def setup_network(self):
         self.alert_filename = os.path.join(self.options.tmpdir, "alert.txt")
diff --git a/test/functional/fundrawtransaction.py b/test/functional/fundrawtransaction.py
index 242b6eed10..dec3d41bfc 100755
--- a/test/functional/fundrawtransaction.py
+++ b/test/functional/fundrawtransaction.py
@@ -14,13 +14,9 @@ def get_unspent(listunspent, amount):
             return utx
     raise AssertionError('Could not find unspent with amount={}'.format(amount))
 
-
 class RawTransactionsTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
-        self.num_nodes = 4
 
     def setup_network(self, split=False):
         self.setup_nodes()
diff --git a/test/functional/getblocktemplate_longpoll.py b/test/functional/getblocktemplate_longpoll.py
index cca30e2688..85d2560244 100755
--- a/test/functional/getblocktemplate_longpoll.py
+++ b/test/functional/getblocktemplate_longpoll.py
@@ -23,11 +23,6 @@ class LongpollThread(threading.Thread):
         self.node.getblocktemplate({'longpollid':self.longpollid})
 
 class GetBlockTemplateLPTest(BitcoinTestFramework):
-    def __init__(self):
-        super().__init__()
-        self.num_nodes = 4
-        self.setup_clean_chain = False
-
     def run_test(self):
         self.log.info("Warning: this test will take about 70 seconds in the best case. Be patient.")
         self.nodes[0].generate(10)
diff --git a/test/functional/getchaintips.py b/test/functional/getchaintips.py
index 15f96c565f..00fc23c6b0 100755
--- a/test/functional/getchaintips.py
+++ b/test/functional/getchaintips.py
@@ -14,13 +14,7 @@ from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import assert_equal
 
 class GetChainTipsTest (BitcoinTestFramework):
-    def __init__(self):
-        super().__init__()
-        self.num_nodes = 4
-        self.setup_clean_chain = False
-
     def run_test (self):
-
         tips = self.nodes[0].getchaintips ()
         assert_equal (len (tips), 1)
         assert_equal (tips[0]['branchlen'], 0)
diff --git a/test/functional/httpbasics.py b/test/functional/httpbasics.py
index 4b32e8d9ca..c7682cb49d 100755
--- a/test/functional/httpbasics.py
+++ b/test/functional/httpbasics.py
@@ -11,10 +11,8 @@ import http.client
 import urllib.parse
 
 class HTTPBasicsTest (BitcoinTestFramework):
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.num_nodes = 3
-        self.setup_clean_chain = False
 
     def setup_network(self):
         self.setup_nodes()
diff --git a/test/functional/import-rescan.py b/test/functional/import-rescan.py
index e85086fbc1..02d7428120 100755
--- a/test/functional/import-rescan.py
+++ b/test/functional/import-rescan.py
@@ -111,8 +111,7 @@ TIMESTAMP_WINDOW = 2 * 60 * 60
 
 
 class ImportRescanTest(BitcoinTestFramework):
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.num_nodes = 2 + len(IMPORT_NODES)
 
     def setup_network(self):
diff --git a/test/functional/importmulti.py b/test/functional/importmulti.py
index 6aae95549d..4c519f40d5 100755
--- a/test/functional/importmulti.py
+++ b/test/functional/importmulti.py
@@ -7,8 +7,7 @@ from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
 
 class ImportMultiTest (BitcoinTestFramework):
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.num_nodes = 2
         self.setup_clean_chain = True
 
diff --git a/test/functional/importprunedfunds.py b/test/functional/importprunedfunds.py
index 94753fe431..df90e9ec17 100755
--- a/test/functional/importprunedfunds.py
+++ b/test/functional/importprunedfunds.py
@@ -6,11 +6,8 @@
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
 
-
 class ImportPrunedFundsTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 2
 
diff --git a/test/functional/invalidateblock.py b/test/functional/invalidateblock.py
index c499d57b90..dd3daf1e07 100755
--- a/test/functional/invalidateblock.py
+++ b/test/functional/invalidateblock.py
@@ -8,9 +8,7 @@ from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
 
 class InvalidateTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 3
 
diff --git a/test/functional/invalidblockrequest.py b/test/functional/invalidblockrequest.py
index eabc0db8df..9f44b44927 100755
--- a/test/functional/invalidblockrequest.py
+++ b/test/functional/invalidblockrequest.py
@@ -23,9 +23,9 @@ class InvalidBlockRequestTest(ComparisonTestFramework):
 
     ''' Can either run this test as 1 node with expected answers, or two and compare them. 
         Change the "outcome" variable from each TestInstance object to only do the comparison. '''
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.num_nodes = 1
+        self.setup_clean_chain = True
 
     def run_test(self):
         test = TestManager(self, self.options.tmpdir)
diff --git a/test/functional/invalidtxrequest.py b/test/functional/invalidtxrequest.py
index a9ac231f09..a22bd8f8cd 100755
--- a/test/functional/invalidtxrequest.py
+++ b/test/functional/invalidtxrequest.py
@@ -19,9 +19,9 @@ class InvalidTxRequestTest(ComparisonTestFramework):
 
     ''' Can either run this test as 1 node with expected answers, or two and compare them. 
         Change the "outcome" variable from each TestInstance object to only do the comparison. '''
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.num_nodes = 1
+        self.setup_clean_chain = True
 
     def run_test(self):
         test = TestManager(self, self.options.tmpdir)
diff --git a/test/functional/keypool-topup.py b/test/functional/keypool-topup.py
index f14a449b59..8302e3ef60 100755
--- a/test/functional/keypool-topup.py
+++ b/test/functional/keypool-topup.py
@@ -20,8 +20,7 @@ from test_framework.util import (
 )
 
 class KeypoolRestoreTest(BitcoinTestFramework):
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 2
         self.extra_args = [['-usehd=0'], ['-usehd=1', '-keypool=100', '-keypoolmin=20']]
diff --git a/test/functional/keypool.py b/test/functional/keypool.py
index 0f84b5c055..b823ca63bb 100755
--- a/test/functional/keypool.py
+++ b/test/functional/keypool.py
@@ -8,6 +8,8 @@ from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
 
 class KeyPoolTest(BitcoinTestFramework):
+    def set_test_params(self):
+        self.num_nodes = 1
 
     def run_test(self):
         nodes = self.nodes
@@ -78,10 +80,5 @@ class KeyPoolTest(BitcoinTestFramework):
         assert_equal(wi['keypoolsize_hd_internal'], 100)
         assert_equal(wi['keypoolsize'], 100)
 
-    def __init__(self):
-        super().__init__()
-        self.setup_clean_chain = False
-        self.num_nodes = 1
-
 if __name__ == '__main__':
     KeyPoolTest().main()
diff --git a/test/functional/listsinceblock.py b/test/functional/listsinceblock.py
index ce2d556ef0..ed1315e805 100755
--- a/test/functional/listsinceblock.py
+++ b/test/functional/listsinceblock.py
@@ -8,11 +8,8 @@ from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import assert_equal
 
 class ListSinceBlockTest (BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
-        self.num_nodes = 4
 
     def run_test(self):
         self.nodes[2].generate(101)
diff --git a/test/functional/listtransactions.py b/test/functional/listtransactions.py
index 9b97028417..5ee85a0dac 100755
--- a/test/functional/listtransactions.py
+++ b/test/functional/listtransactions.py
@@ -16,10 +16,7 @@ def txFromHex(hexstring):
     return tx
 
 class ListTransactionsTest(BitcoinTestFramework):
-    def __init__(self):
-        super().__init__()
-        self.num_nodes = 4
-        self.setup_clean_chain = False
+    def set_test_params(self):
         self.enable_mocktime()
 
     def run_test(self):
diff --git a/test/functional/maxuploadtarget.py b/test/functional/maxuploadtarget.py
index 6bd6a9e34f..1f402798e7 100755
--- a/test/functional/maxuploadtarget.py
+++ b/test/functional/maxuploadtarget.py
@@ -31,8 +31,7 @@ class TestNode(NodeConnCB):
 
 class MaxUploadTest(BitcoinTestFramework):
  
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 1
         self.extra_args = [["-maxuploadtarget=800", "-blockmaxsize=999000"]]
diff --git a/test/functional/mempool_limit.py b/test/functional/mempool_limit.py
index 2777291dd0..e24dc5a464 100755
--- a/test/functional/mempool_limit.py
+++ b/test/functional/mempool_limit.py
@@ -8,9 +8,7 @@ from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
 
 class MempoolLimitTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 1
         self.extra_args = [["-maxmempool=5", "-spendzeroconfchange=0"]]
diff --git a/test/functional/mempool_packages.py b/test/functional/mempool_packages.py
index e225493816..2dedadf8ce 100755
--- a/test/functional/mempool_packages.py
+++ b/test/functional/mempool_packages.py
@@ -12,10 +12,8 @@ MAX_ANCESTORS = 25
 MAX_DESCENDANTS = 25
 
 class MempoolPackagesTest(BitcoinTestFramework):
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.num_nodes = 2
-        self.setup_clean_chain = False
         self.extra_args = [["-maxorphantx=1000"], ["-maxorphantx=1000", "-limitancestorcount=5"]]
 
     # Build a transaction that spends parent_txid:vout
diff --git a/test/functional/mempool_persist.py b/test/functional/mempool_persist.py
index dc5a3263ff..01f65b1373 100755
--- a/test/functional/mempool_persist.py
+++ b/test/functional/mempool_persist.py
@@ -36,12 +36,8 @@ from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
 
 class MempoolPersistTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
-        # We need 3 nodes for this test. Node1 does not have a persistent mempool.
+    def set_test_params(self):
         self.num_nodes = 3
-        self.setup_clean_chain = False
         self.extra_args = [[], ["-persistmempool=0"], []]
 
     def run_test(self):
diff --git a/test/functional/mempool_reorg.py b/test/functional/mempool_reorg.py
index 937bf4bab5..7dfddd3230 100755
--- a/test/functional/mempool_reorg.py
+++ b/test/functional/mempool_reorg.py
@@ -13,10 +13,8 @@ from test_framework.util import *
 
 # Create one-input, one-output, no-fee transaction:
 class MempoolCoinbaseTest(BitcoinTestFramework):
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.num_nodes = 2
-        self.setup_clean_chain = False
         self.extra_args = [["-checkmempool"]] * 2
 
     alert_filename = None  # Set by setup_network
diff --git a/test/functional/mempool_resurrect_test.py b/test/functional/mempool_resurrect_test.py
index a2f6228df9..1263c9306b 100755
--- a/test/functional/mempool_resurrect_test.py
+++ b/test/functional/mempool_resurrect_test.py
@@ -9,12 +9,8 @@ from test_framework.util import *
 
 # Create one-input, one-output, no-fee transaction:
 class MempoolCoinbaseTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.num_nodes = 1
-        self.setup_clean_chain = False
-        # Just need one node for this test
         self.extra_args = [["-checkmempool"]]
 
     def run_test(self):
diff --git a/test/functional/mempool_spendcoinbase.py b/test/functional/mempool_spendcoinbase.py
index 277ea45ad5..58ccd3e373 100755
--- a/test/functional/mempool_spendcoinbase.py
+++ b/test/functional/mempool_spendcoinbase.py
@@ -17,11 +17,8 @@ from test_framework.util import *
 
 # Create one-input, one-output, no-fee transaction:
 class MempoolSpendCoinbaseTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.num_nodes = 1
-        self.setup_clean_chain = False
         self.extra_args = [["-checkmempool"]]
 
     def run_test(self):
diff --git a/test/functional/merkle_blocks.py b/test/functional/merkle_blocks.py
index bcc65c8408..2125c6e17b 100755
--- a/test/functional/merkle_blocks.py
+++ b/test/functional/merkle_blocks.py
@@ -8,11 +8,8 @@ from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
 
 class MerkleBlockTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
-        self.num_nodes = 4
         # Nodes 0/1 are "wallet" nodes, Nodes 2/3 are used for testing
         self.extra_args = [[], [], [], ["-txindex"]]
 
diff --git a/test/functional/mining.py b/test/functional/mining.py
index f3d1f3e90a..93f9838896 100755
--- a/test/functional/mining.py
+++ b/test/functional/mining.py
@@ -27,9 +27,7 @@ def assert_template(node, block, expect, rehash=True):
     assert_equal(rsp, expect)
 
 class MiningTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.num_nodes = 2
         self.setup_clean_chain = False
 
diff --git a/test/functional/multi_rpc.py b/test/functional/multi_rpc.py
index a30e15ace9..a2b346f274 100755
--- a/test/functional/multi_rpc.py
+++ b/test/functional/multi_rpc.py
@@ -12,10 +12,7 @@ import http.client
 import urllib.parse
 
 class HTTPBasicsTest (BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
-        self.setup_clean_chain = False
+    def set_test_params(self):
         self.num_nodes = 2
 
     def setup_chain(self):
diff --git a/test/functional/multiwallet.py b/test/functional/multiwallet.py
index 7381a9fd54..e5453e9aad 100755
--- a/test/functional/multiwallet.py
+++ b/test/functional/multiwallet.py
@@ -12,9 +12,7 @@ from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import assert_equal, assert_raises_jsonrpc
 
 class MultiWalletTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 1
         self.extra_args = [['-wallet=w1', '-wallet=w2', '-wallet=w3']]
diff --git a/test/functional/net.py b/test/functional/net.py
index 3ba3764cf9..37ea6824d5 100755
--- a/test/functional/net.py
+++ b/test/functional/net.py
@@ -17,10 +17,8 @@ from test_framework.util import (
     p2p_port,
 )
 
-
 class NetTest(BitcoinTestFramework):
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 2
 
diff --git a/test/functional/nulldummy.py b/test/functional/nulldummy.py
index 9717add272..60d0d876df 100755
--- a/test/functional/nulldummy.py
+++ b/test/functional/nulldummy.py
@@ -37,8 +37,7 @@ def trueDummy(tx):
 
 class NULLDUMMYTest(BitcoinTestFramework):
 
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.num_nodes = 1
         self.setup_clean_chain = True
         self.extra_args = [['-whitelist=127.0.0.1', '-walletprematurewitness']]
diff --git a/test/functional/p2p-acceptblock.py b/test/functional/p2p-acceptblock.py
index 322cb767db..293bc05539 100755
--- a/test/functional/p2p-acceptblock.py
+++ b/test/functional/p2p-acceptblock.py
@@ -60,8 +60,7 @@ class AcceptBlockTest(BitcoinTestFramework):
                           default=os.getenv("BITCOIND", "bitcoind"),
                           help="bitcoind binary to test")
 
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 2
         self.extra_args = [[], ["-whitelist=127.0.0.1"]]
diff --git a/test/functional/p2p-compactblocks.py b/test/functional/p2p-compactblocks.py
index c5c264765a..9c91c00453 100755
--- a/test/functional/p2p-compactblocks.py
+++ b/test/functional/p2p-compactblocks.py
@@ -89,8 +89,7 @@ class TestNode(NodeConnCB):
         wait_until(lambda: not self.connected, timeout=timeout, lock=mininode_lock)
 
 class CompactBlocksTest(BitcoinTestFramework):
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         # Node0 = pre-segwit, node1 = segwit-aware
         self.num_nodes = 2
diff --git a/test/functional/p2p-feefilter.py b/test/functional/p2p-feefilter.py
index dbccb633a5..8c92365ced 100755
--- a/test/functional/p2p-feefilter.py
+++ b/test/functional/p2p-feefilter.py
@@ -37,11 +37,8 @@ class TestNode(NodeConnCB):
             self.txinvs = []
 
 class FeeFilterTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.num_nodes = 2
-        self.setup_clean_chain = False
 
     def run_test(self):
         node1 = self.nodes[1]
diff --git a/test/functional/p2p-fullblocktest.py b/test/functional/p2p-fullblocktest.py
index e7fe7372c8..cb7bbaf7e5 100755
--- a/test/functional/p2p-fullblocktest.py
+++ b/test/functional/p2p-fullblocktest.py
@@ -49,12 +49,11 @@ class CBrokenBlock(CBlock):
         return r
 
 class FullBlockTest(ComparisonTestFramework):
-
     # Can either run this test as 1 node with expected answers, or two and compare them.
     # Change the "outcome" variable from each TestInstance object to only do the comparison.
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.num_nodes = 1
+        self.setup_clean_chain = True
         self.block_heights = {}
         self.coinbase_key = CECKey()
         self.coinbase_key.set_secretbytes(b"horsebattery")
diff --git a/test/functional/p2p-leaktests.py b/test/functional/p2p-leaktests.py
index f0d4d9a8b8..f27086c97e 100755
--- a/test/functional/p2p-leaktests.py
+++ b/test/functional/p2p-leaktests.py
@@ -92,8 +92,7 @@ class CNodeNoVerackIdle(CLazyNode):
         conn.send_message(msg_getaddr())
 
 class P2PLeakTest(BitcoinTestFramework):
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.num_nodes = 1
         self.extra_args = [['-banscore='+str(banscore)]]
 
diff --git a/test/functional/p2p-mempool.py b/test/functional/p2p-mempool.py
index 34ef249eea..40fcde2605 100755
--- a/test/functional/p2p-mempool.py
+++ b/test/functional/p2p-mempool.py
@@ -13,9 +13,7 @@ from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
 
 class P2PMempoolTests(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 1
         self.extra_args = [["-peerbloomfilters=0"]]
diff --git a/test/functional/p2p-segwit.py b/test/functional/p2p-segwit.py
index 9189f5ef23..8c2d2f0272 100755
--- a/test/functional/p2p-segwit.py
+++ b/test/functional/p2p-segwit.py
@@ -33,8 +33,7 @@ def get_virtual_size(witness_block):
     return vsize
 
 class TestNode(NodeConnCB):
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.getdataset = set()
 
     def on_getdata(self, conn, message):
@@ -109,9 +108,7 @@ def sign_P2PK_witness_input(script, txTo, inIdx, hashtype, value, key):
 
 
 class SegWitTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 3
         self.extra_args = [["-whitelist=127.0.0.1"], ["-whitelist=127.0.0.1", "-acceptnonstdtxn=0"], ["-whitelist=127.0.0.1", "-vbparams=segwit:0:0"]]
diff --git a/test/functional/p2p-timeouts.py b/test/functional/p2p-timeouts.py
index c3b29c215b..51d4769efc 100755
--- a/test/functional/p2p-timeouts.py
+++ b/test/functional/p2p-timeouts.py
@@ -33,8 +33,7 @@ class TestNode(NodeConnCB):
         pass
 
 class TimeoutsTest(BitcoinTestFramework):
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 1
 
diff --git a/test/functional/p2p-versionbits-warning.py b/test/functional/p2p-versionbits-warning.py
index a7aacf908d..5dfac6dd10 100755
--- a/test/functional/p2p-versionbits-warning.py
+++ b/test/functional/p2p-versionbits-warning.py
@@ -28,8 +28,7 @@ class TestNode(NodeConnCB):
         pass
 
 class VersionBitsWarningTest(BitcoinTestFramework):
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 1
 
diff --git a/test/functional/preciousblock.py b/test/functional/preciousblock.py
index 04b41e76ba..40d7bb14ed 100755
--- a/test/functional/preciousblock.py
+++ b/test/functional/preciousblock.py
@@ -35,8 +35,7 @@ def node_sync_via_rpc(nodes):
             unidirectional_node_sync_via_rpc(node_src, node_dest)
 
 class PreciousTest(BitcoinTestFramework):
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 3
 
diff --git a/test/functional/prioritise_transaction.py b/test/functional/prioritise_transaction.py
index 4fc03d2547..7ad368acd4 100755
--- a/test/functional/prioritise_transaction.py
+++ b/test/functional/prioritise_transaction.py
@@ -9,9 +9,7 @@ from test_framework.util import *
 from test_framework.mininode import COIN, MAX_BLOCK_BASE_SIZE
 
 class PrioritiseTransactionTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 2
         self.extra_args = [["-printpriority=1"], ["-printpriority=1"]]
diff --git a/test/functional/proxy_test.py b/test/functional/proxy_test.py
index adbbda278d..26cb645da4 100755
--- a/test/functional/proxy_test.py
+++ b/test/functional/proxy_test.py
@@ -41,13 +41,7 @@ from test_framework.netutil import test_ipv6_local
 
 RANGE_BEGIN = PORT_MIN + 2 * PORT_RANGE  # Start after p2p and rpc ports
 
-
 class ProxyTest(BitcoinTestFramework):
-    def __init__(self):
-        super().__init__()
-        self.num_nodes = 4
-        self.setup_clean_chain = False
-
     def setup_nodes(self):
         self.have_ipv6 = test_ipv6_local()
         # Create two proxies on different ports
diff --git a/test/functional/pruning.py b/test/functional/pruning.py
index 9690428769..a4afbd46d7 100755
--- a/test/functional/pruning.py
+++ b/test/functional/pruning.py
@@ -26,9 +26,7 @@ def calc_usage(blockdir):
     return sum(os.path.getsize(blockdir+f) for f in os.listdir(blockdir) if os.path.isfile(blockdir+f)) / (1024. * 1024.)
 
 class PruneTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 6
 
diff --git a/test/functional/rawtransactions.py b/test/functional/rawtransactions.py
index 6272fc69b7..51dda09ac4 100755
--- a/test/functional/rawtransactions.py
+++ b/test/functional/rawtransactions.py
@@ -17,9 +17,7 @@ from test_framework.util import *
 
 # Create one-input, one-output, no-fee transaction:
 class RawTransactionsTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 3
 
diff --git a/test/functional/receivedby.py b/test/functional/receivedby.py
index b165834169..48eb1c51b5 100755
--- a/test/functional/receivedby.py
+++ b/test/functional/receivedby.py
@@ -23,11 +23,7 @@ def get_sub_array_from_array(object_array, to_match):
     return []
 
 class ReceivedByTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
-        self.num_nodes = 4
-        self.setup_clean_chain = False
+    def set_test_params(self):
         self.enable_mocktime()
 
     def run_test(self):
diff --git a/test/functional/reindex.py b/test/functional/reindex.py
index 0d2a106592..1f684a1afe 100755
--- a/test/functional/reindex.py
+++ b/test/functional/reindex.py
@@ -15,8 +15,7 @@ import time
 
 class ReindexTest(BitcoinTestFramework):
 
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 1
 
diff --git a/test/functional/replace-by-fee.py b/test/functional/replace-by-fee.py
index bc67654987..220e889686 100755
--- a/test/functional/replace-by-fee.py
+++ b/test/functional/replace-by-fee.py
@@ -61,10 +61,8 @@ def make_utxo(node, amount, confirmed=True, scriptPubKey=CScript([1])):
 
 class ReplaceByFeeTest(BitcoinTestFramework):
 
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.num_nodes = 1
-        self.setup_clean_chain = False
         self.extra_args= [["-maxorphantx=1000",
                            "-whitelist=127.0.0.1",
                            "-limitancestorcount=50",
diff --git a/test/functional/resendwallettransactions.py b/test/functional/resendwallettransactions.py
index db6f6eec45..d6ba591391 100755
--- a/test/functional/resendwallettransactions.py
+++ b/test/functional/resendwallettransactions.py
@@ -8,11 +8,9 @@ from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import assert_equal, assert_raises_jsonrpc
 
 class ResendWalletTransactionsTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
-        self.extra_args = [['--walletbroadcast=false']]
+    def set_test_params(self):
         self.num_nodes = 1
+        self.extra_args = [['--walletbroadcast=false']]
 
     def run_test(self):
         # Should raise RPC_WALLET_ERROR (-4) if walletbroadcast is disabled.
diff --git a/test/functional/rest.py b/test/functional/rest.py
index a69dbb5013..437111a4d7 100755
--- a/test/functional/rest.py
+++ b/test/functional/rest.py
@@ -43,8 +43,7 @@ def http_post_call(host, port, path, requestdata = '', response_object = 0):
 class RESTTest (BitcoinTestFramework):
     FORMAT_SEPARATOR = "."
 
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 3
 
diff --git a/test/functional/rpcbind_test.py b/test/functional/rpcbind_test.py
index a7661421ff..0cf64beebd 100755
--- a/test/functional/rpcbind_test.py
+++ b/test/functional/rpcbind_test.py
@@ -11,11 +11,8 @@ from test_framework.test_framework import BitcoinTestFramework, SkipTest
 from test_framework.util import *
 from test_framework.netutil import *
 
-
 class RPCBindTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 1
 
diff --git a/test/functional/rpcnamedargs.py b/test/functional/rpcnamedargs.py
index 3b286000a1..da61cc66e6 100755
--- a/test/functional/rpcnamedargs.py
+++ b/test/functional/rpcnamedargs.py
@@ -10,15 +10,8 @@ from test_framework.util import (
     assert_raises_jsonrpc,
 )
 
-
 class NamedArgumentTest(BitcoinTestFramework):
-    """
-    Test named arguments on RPC calls.
-    """
-
-    def __init__(self):
-        super().__init__()
-        self.setup_clean_chain = False
+    def set_test_params(self):
         self.num_nodes = 1
 
     def run_test(self):
diff --git a/test/functional/segwit.py b/test/functional/segwit.py
index 51eaa34a54..c08fbd3e77 100755
--- a/test/functional/segwit.py
+++ b/test/functional/segwit.py
@@ -75,9 +75,7 @@ def find_unspent(node, min_value):
             return utxo
 
 class SegWitTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 3
         self.extra_args = [["-walletprematurewitness", "-rpcserialversion=0"],
diff --git a/test/functional/sendheaders.py b/test/functional/sendheaders.py
index 6451b097c0..fe577dc20a 100755
--- a/test/functional/sendheaders.py
+++ b/test/functional/sendheaders.py
@@ -174,8 +174,7 @@ class TestNode(NodeConnCB):
         self.send_message(getblocks_message)
 
 class SendHeadersTest(BitcoinTestFramework):
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 2
 
diff --git a/test/functional/signmessages.py b/test/functional/signmessages.py
index 42f6a9daaf..5fdfeceb76 100755
--- a/test/functional/signmessages.py
+++ b/test/functional/signmessages.py
@@ -7,9 +7,7 @@
 from test_framework.test_framework import BitcoinTestFramework
 
 class SignMessagesTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 1
 
diff --git a/test/functional/signrawtransactions.py b/test/functional/signrawtransactions.py
index 415727268a..b47ef93955 100755
--- a/test/functional/signrawtransactions.py
+++ b/test/functional/signrawtransactions.py
@@ -9,8 +9,7 @@ from test_framework.util import *
 
 
 class SignRawTransactionsTest(BitcoinTestFramework):
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 1
 
diff --git a/test/functional/smartfees.py b/test/functional/smartfees.py
index caf3592652..76632fc578 100755
--- a/test/functional/smartfees.py
+++ b/test/functional/smartfees.py
@@ -141,11 +141,8 @@ def check_estimates(node, fees_seen, max_invalid, print_estimates = True):
 
 
 class EstimateFeeTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.num_nodes = 3
-        self.setup_clean_chain = False
 
     def setup_network(self):
         """
diff --git a/test/functional/test_framework/test_framework.py b/test/functional/test_framework/test_framework.py
index 5e3644a914..d860bc5594 100755
--- a/test/functional/test_framework/test_framework.py
+++ b/test/functional/test_framework/test_framework.py
@@ -48,58 +48,30 @@ BITCOIND_PROC_WAIT_TIMEOUT = 60
 class BitcoinTestFramework(object):
     """Base class for a bitcoin test script.
 
-    Individual bitcoin test scripts should subclass this class and override the following methods:
+    Individual bitcoin test scripts should subclass this class and override the run_test() method.
 
-    - __init__()
+    Individual tests can also override the following methods to customize the test setup:
+
+    - set_test_params()
     - add_options()
     - setup_chain()
     - setup_network()
-    - run_test()
+    - setup_nodes()
 
-    The main() method should not be overridden.
+    The __init__() and main() methods should not be overridden.
 
     This class also contains various public and private helper methods."""
 
-    # Methods to override in subclass test scripts.
     def __init__(self):
+        """Sets test framework defaults. Do not override this method. Instead, override the set_test_params() method"""
         self.num_nodes = 4
         self.setup_clean_chain = False
         self.nodes = []
         self.mocktime = 0
-
-    def add_options(self, parser):
-        pass
-
-    def setup_chain(self):
-        self.log.info("Initializing test directory " + self.options.tmpdir)
-        if self.setup_clean_chain:
-            self._initialize_chain_clean()
-        else:
-            self._initialize_chain()
-
-    def setup_network(self):
-        self.setup_nodes()
-
-        # Connect the nodes as a "chain".  This allows us
-        # to split the network between nodes 1 and 2 to get
-        # two halves that can work on competing chains.
-        for i in range(self.num_nodes - 1):
-            connect_nodes_bi(self.nodes, i, i + 1)
-        self.sync_all()
-
-    def setup_nodes(self):
-        extra_args = None
-        if hasattr(self, "extra_args"):
-            extra_args = self.extra_args
-        self.add_nodes(self.num_nodes, extra_args)
-        self.start_nodes()
-
-    def run_test(self):
-        raise NotImplementedError
-
-    # Main function. This should not be overridden by the subclass test scripts.
+        self.set_test_params()
 
     def main(self):
+        """Main function. This should not be overridden by the subclass test scripts."""
 
         parser = optparse.OptionParser(usage="%prog [options]")
         parser.add_option("--nocleanup", dest="nocleanup", default=False, action="store_true",
@@ -203,6 +175,46 @@ class BitcoinTestFramework(object):
             logging.shutdown()
             sys.exit(TEST_EXIT_FAILED)
 
+    # Methods to override in subclass test scripts.
+    def set_test_params(self):
+        """Override this method to change default values for number of nodes, topology, etc"""
+        pass
+
+    def add_options(self, parser):
+        """Override this method to add command-line options to the test"""
+        pass
+
+    def setup_chain(self):
+        """Override this method to customize blockchain setup"""
+        self.log.info("Initializing test directory " + self.options.tmpdir)
+        if self.setup_clean_chain:
+            self._initialize_chain_clean()
+        else:
+            self._initialize_chain()
+
+    def setup_network(self):
+        """Override this method to customize test network topology"""
+        self.setup_nodes()
+
+        # Connect the nodes as a "chain".  This allows us
+        # to split the network between nodes 1 and 2 to get
+        # two halves that can work on competing chains.
+        for i in range(self.num_nodes - 1):
+            connect_nodes_bi(self.nodes, i, i + 1)
+        self.sync_all()
+
+    def setup_nodes(self):
+        """Override this method to customize test node setup"""
+        extra_args = None
+        if hasattr(self, "extra_args"):
+            extra_args = self.extra_args
+        self.add_nodes(self.num_nodes, extra_args)
+        self.start_nodes()
+
+    def run_test(self):
+        """Override this method to define test logic"""
+        raise NotImplementedError
+
     # Public helper methods. These can be accessed by the subclass test scripts.
 
     def add_nodes(self, num_nodes, extra_args=None, rpchost=None, timewait=None, binary=None):
@@ -442,8 +454,7 @@ class ComparisonTestFramework(BitcoinTestFramework):
     - 2 binaries: 1 test binary, 1 ref binary
     - n>2 binaries: 1 test binary, n-1 ref binaries"""
 
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.num_nodes = 2
         self.setup_clean_chain = True
 
diff --git a/test/functional/txn_clone.py b/test/functional/txn_clone.py
index 9b81af96cf..fc133050b0 100755
--- a/test/functional/txn_clone.py
+++ b/test/functional/txn_clone.py
@@ -8,12 +8,6 @@ from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
 
 class TxnMallTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
-        self.num_nodes = 4
-        self.setup_clean_chain = False
-
     def add_options(self, parser):
         parser.add_option("--mineblock", dest="mine_block", default=False, action="store_true",
                           help="Test double-spend of 1-confirmed transaction")
diff --git a/test/functional/txn_doublespend.py b/test/functional/txn_doublespend.py
index 1bd3b3271c..ff24fac254 100755
--- a/test/functional/txn_doublespend.py
+++ b/test/functional/txn_doublespend.py
@@ -9,11 +9,6 @@ from test_framework.util import *
 
 class TxnMallTest(BitcoinTestFramework):
 
-    def __init__(self):
-        super().__init__()
-        self.num_nodes = 4
-        self.setup_clean_chain = False
-
     def add_options(self, parser):
         parser.add_option("--mineblock", dest="mine_block", default=False, action="store_true",
                           help="Test double-spend of 1-confirmed transaction")
diff --git a/test/functional/uptime.py b/test/functional/uptime.py
index b20d6f5cb6..78236b2393 100755
--- a/test/functional/uptime.py
+++ b/test/functional/uptime.py
@@ -13,9 +13,7 @@ from test_framework.test_framework import BitcoinTestFramework
 
 
 class UptimeTest(BitcoinTestFramework):
-    def __init__(self):
-        super().__init__()
-
+    def set_test_params(self):
         self.num_nodes = 1
         self.setup_clean_chain = True
 
diff --git a/test/functional/wallet-accounts.py b/test/functional/wallet-accounts.py
index 158aa9ae89..40726d2a76 100755
--- a/test/functional/wallet-accounts.py
+++ b/test/functional/wallet-accounts.py
@@ -17,9 +17,7 @@ from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import assert_equal
 
 class WalletAccountsTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 1
         self.extra_args = [[]]
diff --git a/test/functional/wallet-dump.py b/test/functional/wallet-dump.py
index e0381b9809..39b7164d6e 100755
--- a/test/functional/wallet-dump.py
+++ b/test/functional/wallet-dump.py
@@ -56,10 +56,7 @@ def read_dump(file_name, addrs, hd_master_addr_old):
 
 
 class WalletDumpTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
-        self.setup_clean_chain = False
+    def set_test_params(self):
         self.num_nodes = 1
         self.extra_args = [["-keypool=90"]]
 
diff --git a/test/functional/wallet-encryption.py b/test/functional/wallet-encryption.py
index 2f38e6fee8..f63bb2ea5e 100755
--- a/test/functional/wallet-encryption.py
+++ b/test/functional/wallet-encryption.py
@@ -13,9 +13,7 @@ from test_framework.util import (
 )
 
 class WalletEncryptionTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 1
 
diff --git a/test/functional/wallet-hd.py b/test/functional/wallet-hd.py
index 13b9dd9a90..68b5e5b8d4 100755
--- a/test/functional/wallet-hd.py
+++ b/test/functional/wallet-hd.py
@@ -11,11 +11,8 @@ from test_framework.util import (
 )
 import shutil
 
-
 class WalletHDTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 2
         self.extra_args = [['-usehd=0'], ['-usehd=1', '-keypool=0']]
diff --git a/test/functional/wallet.py b/test/functional/wallet.py
index 7190de94b6..79727f9be6 100755
--- a/test/functional/wallet.py
+++ b/test/functional/wallet.py
@@ -7,17 +7,8 @@ from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
 
 class WalletTest(BitcoinTestFramework):
-
-    def check_fee_amount(self, curr_balance, balance_with_fee, fee_per_byte, tx_size):
-        """Return curr_balance after asserting the fee was in range"""
-        fee = balance_with_fee - curr_balance
-        assert_fee_amount(fee, tx_size, fee_per_byte * 1000)
-        return curr_balance
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
-        self.num_nodes = 4
         self.extra_args = [['-usehd={:d}'.format(i%2==0)] for i in range(4)]
 
     def setup_network(self):
@@ -30,8 +21,13 @@ class WalletTest(BitcoinTestFramework):
         connect_nodes_bi(self.nodes,0,2)
         self.sync_all([self.nodes[0:3]])
 
-    def run_test(self):
+    def check_fee_amount(self, curr_balance, balance_with_fee, fee_per_byte, tx_size):
+        """Return curr_balance after asserting the fee was in range"""
+        fee = balance_with_fee - curr_balance
+        assert_fee_amount(fee, tx_size, fee_per_byte * 1000)
+        return curr_balance
 
+    def run_test(self):
         # Check that there's no UTXO on none of the nodes
         assert_equal(len(self.nodes[0].listunspent()), 0)
         assert_equal(len(self.nodes[1].listunspent()), 0)
diff --git a/test/functional/walletbackup.py b/test/functional/walletbackup.py
index 688cd6d0c8..36714164a8 100755
--- a/test/functional/walletbackup.py
+++ b/test/functional/walletbackup.py
@@ -37,11 +37,8 @@ from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
 
 class WalletBackupTest(BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
-        self.num_nodes = 4
         # nodes 1, 2,3 are spenders, let's give them a keypool=100
         self.extra_args = [["-keypool=100"], ["-keypool=100"], ["-keypool=100"], []]
 
diff --git a/test/functional/zapwallettxes.py b/test/functional/zapwallettxes.py
index 1005a4b95f..c001517a6d 100755
--- a/test/functional/zapwallettxes.py
+++ b/test/functional/zapwallettxes.py
@@ -20,9 +20,7 @@ from test_framework.util import (assert_equal,
                                  )
 
 class ZapWalletTXesTest (BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 2
 
diff --git a/test/functional/zmq_test.py b/test/functional/zmq_test.py
index b5a22ea07f..3f2668ee87 100755
--- a/test/functional/zmq_test.py
+++ b/test/functional/zmq_test.py
@@ -13,9 +13,7 @@ from test_framework.util import (assert_equal,
                                  )
 
 class ZMQTest (BitcoinTestFramework):
-
-    def __init__(self):
-        super().__init__()
+    def set_test_params(self):
         self.num_nodes = 2
 
     def setup_nodes(self):