Merge #8056: [qa] Remove hardcoded "4 nodes" from test_framework

fad68f7 [qa] Reduce node count for some tests (MarcoFalke)
fac9349 [qa] Remove hardcoded "4 nodes" from test_framework (MarcoFalke)

58 files changed, 291 insertions, 138 deletions

diff --git a/qa/rpc-tests/abandonconflict.py b/qa/rpc-tests/abandonconflict.py
index b6c4b9db48..c50c3cc562 100755
--- a/qa/rpc-tests/abandonconflict.py
+++ b/qa/rpc-tests/abandonconflict.py
@@ -9,6 +9,10 @@ from test_framework.util import *
 import urllib.parse
 
 class AbandonConflictTest(BitcoinTestFramework):
+    def __init__(self):
+        super().__init__()
+        self.num_nodes = 2
+        self.setup_clean_chain = False
 
     def setup_network(self):
         self.nodes = []
diff --git a/qa/rpc-tests/bip65-cltv-p2p.py b/qa/rpc-tests/bip65-cltv-p2p.py
index 60923b9dda..754b6873b7 100755
--- a/qa/rpc-tests/bip65-cltv-p2p.py
+++ b/qa/rpc-tests/bip65-cltv-p2p.py
@@ -37,11 +37,12 @@ Mine 1 old version block, see that the node rejects.
 class BIP65Test(ComparisonTestFramework):
 
     def __init__(self):
+        super().__init__()
         self.num_nodes = 1
 
     def setup_network(self):
         # Must set the blockversion for this test
-        self.nodes = start_nodes(1, self.options.tmpdir,
+        self.nodes = start_nodes(self.num_nodes, self.options.tmpdir,
                                  extra_args=[['-debug', '-whitelist=127.0.0.1', '-blockversion=3']],
                                  binary=[self.options.testbinary])
 
diff --git a/qa/rpc-tests/bip65-cltv.py b/qa/rpc-tests/bip65-cltv.py
index 9d83fc947b..abba7fc20e 100755
--- a/qa/rpc-tests/bip65-cltv.py
+++ b/qa/rpc-tests/bip65-cltv.py
@@ -11,6 +11,10 @@ from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
 
 class BIP65Test(BitcoinTestFramework):
+    def __init__(self):
+        super().__init__()
+        self.num_nodes = 3
+        self.setup_clean_chain = False
 
     def setup_network(self):
         self.nodes = []
diff --git a/qa/rpc-tests/bip68-112-113-p2p.py b/qa/rpc-tests/bip68-112-113-p2p.py
index eedb60e3a0..8ba0704384 100755
--- a/qa/rpc-tests/bip68-112-113-p2p.py
+++ b/qa/rpc-tests/bip68-112-113-p2p.py
@@ -94,11 +94,12 @@ def all_rlt_txs(txarray):
 
 class BIP68_112_113Test(ComparisonTestFramework):
     def __init__(self):
+        super().__init__()
         self.num_nodes = 1
 
     def setup_network(self):
         # Must set the blockversion for this test
-        self.nodes = start_nodes(1, self.options.tmpdir,
+        self.nodes = start_nodes(self.num_nodes, self.options.tmpdir,
                                  extra_args=[['-debug', '-whitelist=127.0.0.1', '-blockversion=4']],
                                  binary=[self.options.testbinary])
 
diff --git a/qa/rpc-tests/bip68-sequence.py b/qa/rpc-tests/bip68-sequence.py
index 717f7562cd..a12bf10ebd 100755
--- a/qa/rpc-tests/bip68-sequence.py
+++ b/qa/rpc-tests/bip68-sequence.py
@@ -22,6 +22,10 @@ SEQUENCE_LOCKTIME_MASK = 0x0000ffff
 NOT_FINAL_ERROR = "64: non-BIP68-final"
 
 class BIP68Test(BitcoinTestFramework):
+    def __init__(self):
+        super().__init__()
+        self.num_nodes = 2
+        self.setup_clean_chain = False
 
     def setup_network(self):
         self.nodes = []
diff --git a/qa/rpc-tests/bip9-softforks.py b/qa/rpc-tests/bip9-softforks.py
index a8fb878dcb..aae258315e 100755
--- a/qa/rpc-tests/bip9-softforks.py
+++ b/qa/rpc-tests/bip9-softforks.py
@@ -32,10 +32,11 @@ test that enforcement has triggered
 class BIP9SoftForksTest(ComparisonTestFramework):
 
     def __init__(self):
+        super().__init__()
         self.num_nodes = 1
 
     def setup_network(self):
-        self.nodes = start_nodes(1, self.options.tmpdir,
+        self.nodes = start_nodes(self.num_nodes, self.options.tmpdir,
                                  extra_args=[['-debug', '-whitelist=127.0.0.1']],
                                  binary=[self.options.testbinary])
 
diff --git a/qa/rpc-tests/bipdersig-p2p.py b/qa/rpc-tests/bipdersig-p2p.py
index c462730840..4e4936a4ae 100755
--- a/qa/rpc-tests/bipdersig-p2p.py
+++ b/qa/rpc-tests/bipdersig-p2p.py
@@ -45,11 +45,12 @@ Mine 1 old version block, see that the node rejects.
 class BIP66Test(ComparisonTestFramework):
 
     def __init__(self):
+        super().__init__()
         self.num_nodes = 1
 
     def setup_network(self):
         # Must set the blockversion for this test
-        self.nodes = start_nodes(1, self.options.tmpdir, 
+        self.nodes = start_nodes(self.num_nodes, self.options.tmpdir,
                                  extra_args=[['-debug', '-whitelist=127.0.0.1', '-blockversion=2']],
                                  binary=[self.options.testbinary])
 
diff --git a/qa/rpc-tests/bipdersig.py b/qa/rpc-tests/bipdersig.py
index f2d2c14a72..17c2ced79a 100755
--- a/qa/rpc-tests/bipdersig.py
+++ b/qa/rpc-tests/bipdersig.py
@@ -11,6 +11,10 @@ from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
 
 class BIP66Test(BitcoinTestFramework):
+    def __init__(self):
+        super().__init__()
+        self.num_nodes = 3
+        self.setup_clean_chain = False
 
     def setup_network(self):
         self.nodes = []
diff --git a/qa/rpc-tests/blockchain.py b/qa/rpc-tests/blockchain.py
index c84047b5dd..410b85d15e 100755
--- a/qa/rpc-tests/blockchain.py
+++ b/qa/rpc-tests/blockchain.py
@@ -13,7 +13,6 @@ from decimal import Decimal
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.authproxy import JSONRPCException
 from test_framework.util import (
-    initialize_chain,
     assert_equal,
     assert_raises,
     assert_is_hex_string,
@@ -32,12 +31,13 @@ class BlockchainTest(BitcoinTestFramework):
 
     """
 
-    def setup_chain(self):
-        print("Initializing test directory " + self.options.tmpdir)
-        initialize_chain(self.options.tmpdir)
+    def __init__(self):
+        super().__init__()
+        self.setup_clean_chain = False
+        self.num_nodes = 2
 
     def setup_network(self, split=False):
-        self.nodes = start_nodes(2, self.options.tmpdir)
+        self.nodes = start_nodes(self.num_nodes, self.options.tmpdir)
         connect_nodes_bi(self.nodes, 0, 1)
         self.is_network_split = False
         self.sync_all()
diff --git a/qa/rpc-tests/decodescript.py b/qa/rpc-tests/decodescript.py
index 0037542e62..24768c2655 100755
--- a/qa/rpc-tests/decodescript.py
+++ b/qa/rpc-tests/decodescript.py
@@ -11,12 +11,13 @@ from io import BytesIO
 class DecodeScriptTest(BitcoinTestFramework):
     """Tests decoding scripts via RPC command "decodescript"."""
 
-    def setup_chain(self):
-        print('Initializing test directory ' + self.options.tmpdir)
-        initialize_chain_clean(self.options.tmpdir, 1)
+    def __init__(self):
+        super().__init__()
+        self.setup_clean_chain = True
+        self.num_nodes = 1
 
     def setup_network(self, split=False):
-        self.nodes = start_nodes(1, self.options.tmpdir)
+        self.nodes = start_nodes(self.num_nodes, self.options.tmpdir)
         self.is_network_split = False
 
     def decodescript_script_sig(self):
diff --git a/qa/rpc-tests/disablewallet.py b/qa/rpc-tests/disablewallet.py
index b25d2ba335..36c147edad 100755
--- a/qa/rpc-tests/disablewallet.py
+++ b/qa/rpc-tests/disablewallet.py
@@ -13,12 +13,13 @@ from test_framework.util import *
 
 class DisableWalletTest (BitcoinTestFramework):
 
-    def setup_chain(self):
-        print("Initializing test directory "+self.options.tmpdir)
-        initialize_chain_clean(self.options.tmpdir, 1)
+    def __init__(self):
+        super().__init__()
+        self.setup_clean_chain = True
+        self.num_nodes = 1
 
     def setup_network(self, split=False):
-        self.nodes = start_nodes(1, self.options.tmpdir, [['-disablewallet']])
+        self.nodes = start_nodes(self.num_nodes, self.options.tmpdir, [['-disablewallet']])
         self.is_network_split = False
         self.sync_all()
 
diff --git a/qa/rpc-tests/forknotify.py b/qa/rpc-tests/forknotify.py
index 421f3dd872..5a3f75c808 100755
--- a/qa/rpc-tests/forknotify.py
+++ b/qa/rpc-tests/forknotify.py
@@ -12,6 +12,11 @@ from test_framework.util import *
 
 class ForkNotifyTest(BitcoinTestFramework):
 
+    def __init__(self):
+        super().__init__()
+        self.num_nodes = 2
+        self.setup_clean_chain = False
+
     alert_filename = None  # Set by setup_network
 
     def setup_network(self):
diff --git a/qa/rpc-tests/fundrawtransaction.py b/qa/rpc-tests/fundrawtransaction.py
index 74849603f7..57b850a6a9 100755
--- a/qa/rpc-tests/fundrawtransaction.py
+++ b/qa/rpc-tests/fundrawtransaction.py
@@ -9,12 +9,13 @@ from test_framework.util import *
 # Create one-input, one-output, no-fee transaction:
 class RawTransactionsTest(BitcoinTestFramework):
 
-    def setup_chain(self):
-        print(("Initializing test directory "+self.options.tmpdir))
-        initialize_chain_clean(self.options.tmpdir, 4)
+    def __init__(self):
+        super().__init__()
+        self.setup_clean_chain = True
+        self.num_nodes = 4
 
     def setup_network(self, split=False):
-        self.nodes = start_nodes(4, self.options.tmpdir)
+        self.nodes = start_nodes(self.num_nodes, self.options.tmpdir)
 
         connect_nodes_bi(self.nodes,0,1)
         connect_nodes_bi(self.nodes,1,2)
@@ -521,7 +522,7 @@ class RawTransactionsTest(BitcoinTestFramework):
         stop_nodes(self.nodes)
         wait_bitcoinds()
 
-        self.nodes = start_nodes(4, self.options.tmpdir)
+        self.nodes = start_nodes(self.num_nodes, self.options.tmpdir)
         # This test is not meant to test fee estimation and we'd like
         # to be sure all txs are sent at a consistent desired feerate
         for node in self.nodes:
diff --git a/qa/rpc-tests/getblocktemplate_longpoll.py b/qa/rpc-tests/getblocktemplate_longpoll.py
index e443347077..3cddf4046a 100755
--- a/qa/rpc-tests/getblocktemplate_longpoll.py
+++ b/qa/rpc-tests/getblocktemplate_longpoll.py
@@ -26,6 +26,11 @@ class GetBlockTemplateLPTest(BitcoinTestFramework):
     Test longpolling with getblocktemplate.
     '''
 
+    def __init__(self):
+        super().__init__()
+        self.num_nodes = 4
+        self.setup_clean_chain = False
+
     def run_test(self):
         print("Warning: this test will take about 70 seconds in the best case. Be patient.")
         self.nodes[0].generate(10)
diff --git a/qa/rpc-tests/getblocktemplate_proposals.py b/qa/rpc-tests/getblocktemplate_proposals.py
index 1ad2af4c2e..7a4f8f8fdc 100755
--- a/qa/rpc-tests/getblocktemplate_proposals.py
+++ b/qa/rpc-tests/getblocktemplate_proposals.py
@@ -70,6 +70,15 @@ class GetBlockTemplateProposalTest(BitcoinTestFramework):
     Test block proposals with getblocktemplate.
     '''
 
+    def __init__(self):
+        super().__init__()
+        self.num_nodes = 2
+        self.setup_clean_chain = False
+
+    def setup_network(self):
+        self.nodes = self.setup_nodes()
+        connect_nodes_bi(self.nodes, 0, 1)
+
     def run_test(self):
         node = self.nodes[0]
         node.generate(1) # Mine a block to leave initial block download
diff --git a/qa/rpc-tests/getchaintips.py b/qa/rpc-tests/getchaintips.py
index da354b0c97..1c66b8c289 100755
--- a/qa/rpc-tests/getchaintips.py
+++ b/qa/rpc-tests/getchaintips.py
@@ -11,9 +11,12 @@ 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):
-        BitcoinTestFramework.run_test (self)
 
         tips = self.nodes[0].getchaintips ()
         assert_equal (len (tips), 1)
diff --git a/qa/rpc-tests/httpbasics.py b/qa/rpc-tests/httpbasics.py
index c62edc8e13..10bc927e1a 100755
--- a/qa/rpc-tests/httpbasics.py
+++ b/qa/rpc-tests/httpbasics.py
@@ -14,8 +14,13 @@ import http.client
 import urllib.parse
 
 class HTTPBasicsTest (BitcoinTestFramework):
-    def setup_nodes(self):
-        return start_nodes(4, self.options.tmpdir)
+    def __init__(self):
+        super().__init__()
+        self.num_nodes = 3
+        self.setup_clean_chain = False
+
+    def setup_network(self):
+        self.nodes = self.setup_nodes()
 
     def run_test(self):
 
diff --git a/qa/rpc-tests/importprunedfunds.py b/qa/rpc-tests/importprunedfunds.py
index def1d891c3..d86f51b7f3 100755
--- a/qa/rpc-tests/importprunedfunds.py
+++ b/qa/rpc-tests/importprunedfunds.py
@@ -9,12 +9,13 @@ import decimal
 
 class ImportPrunedFundsTest(BitcoinTestFramework):
 
-    def setup_chain(self):
-        print("Initializing test directory "+self.options.tmpdir)
-        initialize_chain_clean(self.options.tmpdir, 4)
+    def __init__(self):
+        super().__init__()
+        self.setup_clean_chain = True
+        self.num_nodes = 2
 
     def setup_network(self, split=False):
-        self.nodes = start_nodes(2, self.options.tmpdir)
+        self.nodes = start_nodes(self.num_nodes, self.options.tmpdir)
         connect_nodes_bi(self.nodes,0,1)
         self.is_network_split=False
         self.sync_all()
diff --git a/qa/rpc-tests/invalidateblock.py b/qa/rpc-tests/invalidateblock.py
index 2e3a449f5e..0faadd33ab 100755
--- a/qa/rpc-tests/invalidateblock.py
+++ b/qa/rpc-tests/invalidateblock.py
@@ -13,10 +13,11 @@ from test_framework.util import *
 class InvalidateTest(BitcoinTestFramework):
     
         
-    def setup_chain(self):
-        print("Initializing test directory "+self.options.tmpdir)
-        initialize_chain_clean(self.options.tmpdir, 3)
-                 
+    def __init__(self):
+        super().__init__()
+        self.setup_clean_chain = True
+        self.num_nodes = 3
+
     def setup_network(self):
         self.nodes = []
         self.is_network_split = False 
diff --git a/qa/rpc-tests/invalidblockrequest.py b/qa/rpc-tests/invalidblockrequest.py
index 78dc7199da..3d8107a76c 100755
--- a/qa/rpc-tests/invalidblockrequest.py
+++ b/qa/rpc-tests/invalidblockrequest.py
@@ -25,6 +25,7 @@ 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__()
         self.num_nodes = 1
 
     def run_test(self):
diff --git a/qa/rpc-tests/invalidtxrequest.py b/qa/rpc-tests/invalidtxrequest.py
index d4200b0e88..93205d79de 100755
--- a/qa/rpc-tests/invalidtxrequest.py
+++ b/qa/rpc-tests/invalidtxrequest.py
@@ -19,6 +19,7 @@ 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__()
         self.num_nodes = 1
 
     def run_test(self):
diff --git a/qa/rpc-tests/keypool.py b/qa/rpc-tests/keypool.py
index bdc144bfbc..c75303ecbf 100755
--- a/qa/rpc-tests/keypool.py
+++ b/qa/rpc-tests/keypool.py
@@ -5,8 +5,6 @@
 
 # Exercise the wallet keypool, and interaction with wallet encryption/locking
 
-# Add python-bitcoinrpc to module search path:
-
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
 
@@ -65,12 +63,13 @@ class KeyPoolTest(BitcoinTestFramework):
         except JSONRPCException as e:
             assert(e.error['code']==-12)
 
-    def setup_chain(self):
-        print("Initializing test directory "+self.options.tmpdir)
-        initialize_chain(self.options.tmpdir)
+    def __init__(self):
+        super().__init__()
+        self.setup_clean_chain = False
+        self.num_nodes = 1
 
     def setup_network(self):
-        self.nodes = start_nodes(1, self.options.tmpdir)
+        self.nodes = self.setup_nodes()
 
 if __name__ == '__main__':
     KeyPoolTest().main()
diff --git a/qa/rpc-tests/listtransactions.py b/qa/rpc-tests/listtransactions.py
index 8dad687edd..5ec6ce17e0 100755
--- a/qa/rpc-tests/listtransactions.py
+++ b/qa/rpc-tests/listtransactions.py
@@ -17,11 +17,15 @@ def txFromHex(hexstring):
     return tx
 
 class ListTransactionsTest(BitcoinTestFramework):
+    def __init__(self):
+        super().__init__()
+        self.num_nodes = 4
+        self.setup_clean_chain = False
 
     def setup_nodes(self):
         #This test requires mocktime
         enable_mocktime()
-        return start_nodes(4, self.options.tmpdir)
+        return start_nodes(self.num_nodes, self.options.tmpdir)
 
     def run_test(self):
         # Simple send, 0 to 1:
diff --git a/qa/rpc-tests/maxblocksinflight.py b/qa/rpc-tests/maxblocksinflight.py
index 6f105a77e3..1df1c484be 100755
--- a/qa/rpc-tests/maxblocksinflight.py
+++ b/qa/rpc-tests/maxblocksinflight.py
@@ -76,12 +76,13 @@ class MaxBlocksInFlightTest(BitcoinTestFramework):
                           default=os.getenv("BITCOIND", "bitcoind"),
                           help="Binary to test max block requests behavior")
 
-    def setup_chain(self):
-        print("Initializing test directory "+self.options.tmpdir)
-        initialize_chain_clean(self.options.tmpdir, 1)
+    def __init__(self):
+        super().__init__()
+        self.setup_clean_chain = True
+        self.num_nodes = 1
 
     def setup_network(self):
-        self.nodes = start_nodes(1, self.options.tmpdir,
+        self.nodes = start_nodes(self.num_nodes, self.options.tmpdir,
                                  extra_args=[['-debug', '-whitelist=127.0.0.1']],
                                  binary=[self.options.testbinary])
 
diff --git a/qa/rpc-tests/maxuploadtarget.py b/qa/rpc-tests/maxuploadtarget.py
index ec802d8155..5087f07620 100755
--- a/qa/rpc-tests/maxuploadtarget.py
+++ b/qa/rpc-tests/maxuploadtarget.py
@@ -80,17 +80,19 @@ class TestNode(NodeConnCB):
         return success
 
 class MaxUploadTest(BitcoinTestFramework):
-    def __init__(self):
-        self.utxo = []
-        self.txouts = gen_return_txouts()
  
     def add_options(self, parser):
         parser.add_option("--testbinary", dest="testbinary",
                           default=os.getenv("BITCOIND", "bitcoind"),
                           help="bitcoind binary to test")
 
-    def setup_chain(self):
-        initialize_chain_clean(self.options.tmpdir, 2)
+    def __init__(self):
+        super().__init__()
+        self.setup_clean_chain = True
+        self.num_nodes = 1
+
+        self.utxo = []
+        self.txouts = gen_return_txouts()
 
     def setup_network(self):
         # Start a node with maxuploadtarget of 200 MB (/24h)
diff --git a/qa/rpc-tests/mempool_limit.py b/qa/rpc-tests/mempool_limit.py
index bc208709e9..4438c152df 100755
--- a/qa/rpc-tests/mempool_limit.py
+++ b/qa/rpc-tests/mempool_limit.py
@@ -10,9 +10,6 @@ from test_framework.util import *
 
 class MempoolLimitTest(BitcoinTestFramework):
 
-    def __init__(self):
-        self.txouts = gen_return_txouts()
-
     def setup_network(self):
         self.nodes = []
         self.nodes.append(start_node(0, self.options.tmpdir, ["-maxmempool=5", "-spendzeroconfchange=0", "-debug"]))
@@ -20,9 +17,12 @@ class MempoolLimitTest(BitcoinTestFramework):
         self.sync_all()
         self.relayfee = self.nodes[0].getnetworkinfo()['relayfee']
 
-    def setup_chain(self):
-        print("Initializing test directory "+self.options.tmpdir)
-        initialize_chain_clean(self.options.tmpdir, 2)
+    def __init__(self):
+        super().__init__()
+        self.setup_clean_chain = True
+        self.num_nodes = 1
+
+        self.txouts = gen_return_txouts()
 
     def run_test(self):
         txids = []
diff --git a/qa/rpc-tests/mempool_packages.py b/qa/rpc-tests/mempool_packages.py
index 7ac85c1b6d..693ff593b3 100755
--- a/qa/rpc-tests/mempool_packages.py
+++ b/qa/rpc-tests/mempool_packages.py
@@ -13,6 +13,10 @@ MAX_ANCESTORS = 25
 MAX_DESCENDANTS = 25
 
 class MempoolPackagesTest(BitcoinTestFramework):
+    def __init__(self):
+        super().__init__()
+        self.num_nodes = 2
+        self.setup_clean_chain = False
 
     def setup_network(self):
         self.nodes = []
diff --git a/qa/rpc-tests/mempool_reorg.py b/qa/rpc-tests/mempool_reorg.py
index 608e9d0a06..301b094eb0 100755
--- a/qa/rpc-tests/mempool_reorg.py
+++ b/qa/rpc-tests/mempool_reorg.py
@@ -13,6 +13,10 @@ from test_framework.util import *
 
 # Create one-input, one-output, no-fee transaction:
 class MempoolCoinbaseTest(BitcoinTestFramework):
+    def __init__(self):
+        super().__init__()
+        self.num_nodes = 2
+        self.setup_clean_chain = False
 
     alert_filename = None  # Set by setup_network
 
diff --git a/qa/rpc-tests/mempool_resurrect_test.py b/qa/rpc-tests/mempool_resurrect_test.py
index b4d9f0a1a2..3db12cbf76 100755
--- a/qa/rpc-tests/mempool_resurrect_test.py
+++ b/qa/rpc-tests/mempool_resurrect_test.py
@@ -14,6 +14,11 @@ from test_framework.util import *
 # Create one-input, one-output, no-fee transaction:
 class MempoolCoinbaseTest(BitcoinTestFramework):
 
+    def __init__(self):
+        super().__init__()
+        self.num_nodes = 1
+        self.setup_clean_chain = False
+
     def setup_network(self):
         # Just need one node for this test
         args = ["-checkmempool", "-debug=mempool"]
diff --git a/qa/rpc-tests/mempool_spendcoinbase.py b/qa/rpc-tests/mempool_spendcoinbase.py
index c23f5ef10a..d5e4bf52d2 100755
--- a/qa/rpc-tests/mempool_spendcoinbase.py
+++ b/qa/rpc-tests/mempool_spendcoinbase.py
@@ -19,6 +19,11 @@ from test_framework.util import *
 # Create one-input, one-output, no-fee transaction:
 class MempoolSpendCoinbaseTest(BitcoinTestFramework):
 
+    def __init__(self):
+        super().__init__()
+        self.num_nodes = 1
+        self.setup_clean_chain = False
+
     def setup_network(self):
         # Just need one node for this test
         args = ["-checkmempool", "-debug=mempool"]
diff --git a/qa/rpc-tests/merkle_blocks.py b/qa/rpc-tests/merkle_blocks.py
index 9419d9a714..b2155d7fc3 100755
--- a/qa/rpc-tests/merkle_blocks.py
+++ b/qa/rpc-tests/merkle_blocks.py
@@ -12,9 +12,10 @@ from test_framework.util import *
 
 class MerkleBlockTest(BitcoinTestFramework):
 
-    def setup_chain(self):
-        print("Initializing test directory "+self.options.tmpdir)
-        initialize_chain_clean(self.options.tmpdir, 4)
+    def __init__(self):
+        super().__init__()
+        self.setup_clean_chain = True
+        self.num_nodes = 4
 
     def setup_network(self):
         self.nodes = []
diff --git a/qa/rpc-tests/multi_rpc.py b/qa/rpc-tests/multi_rpc.py
index 577d80949d..24373b257d 100755
--- a/qa/rpc-tests/multi_rpc.py
+++ b/qa/rpc-tests/multi_rpc.py
@@ -8,18 +8,21 @@
 #
 
 from test_framework.test_framework import BitcoinTestFramework
-from test_framework.util import *
+from test_framework.util import str_to_b64str, assert_equal
 
+import os
 import http.client
 import urllib.parse
 
 class HTTPBasicsTest (BitcoinTestFramework):
-    def setup_nodes(self):
-        return start_nodes(4, self.options.tmpdir)
+
+    def __init__(self):
+        super().__init__()
+        self.setup_clean_chain = False
+        self.num_nodes = 1
 
     def setup_chain(self):
-        print("Initializing test directory "+self.options.tmpdir)
-        initialize_chain(self.options.tmpdir)
+        super().setup_chain()
         #Append rpcauth to bitcoin.conf before initialization
         rpcauth = "rpcauth=rt:93648e835a54c573682c2eb19f882535$7681e9c5b74bdd85e78166031d2058e1069b3ed7ed967c93fc63abba06f31144"
         rpcauth2 = "rpcauth=rt2:f8607b1a88861fac29dfccf9b52ff9f$ff36a0c23c8c62b4846112e50fa888416e94c17bfd4c42f88fd8f55ec6a3137e"
@@ -27,6 +30,9 @@ class HTTPBasicsTest (BitcoinTestFramework):
             f.write(rpcauth+"\n")
             f.write(rpcauth2+"\n")
 
+    def setup_network(self):
+        self.nodes = self.setup_nodes()
+
     def run_test(self):
 
         ##################################################
diff --git a/qa/rpc-tests/nodehandling.py b/qa/rpc-tests/nodehandling.py
index 1b6ba021a0..e9682c4908 100755
--- a/qa/rpc-tests/nodehandling.py
+++ b/qa/rpc-tests/nodehandling.py
@@ -14,6 +14,12 @@ import http.client
 import urllib.parse
 
 class NodeHandlingTest (BitcoinTestFramework):
+
+    def __init__(self):
+        super().__init__()
+        self.num_nodes = 4
+        self.setup_clean_chain = False
+
     def run_test(self):
         ###########################
         # setban/listbanned tests #
diff --git a/qa/rpc-tests/p2p-acceptblock.py b/qa/rpc-tests/p2p-acceptblock.py
index 21e4c2f468..015ec34eff 100755
--- a/qa/rpc-tests/p2p-acceptblock.py
+++ b/qa/rpc-tests/p2p-acceptblock.py
@@ -111,8 +111,10 @@ class AcceptBlockTest(BitcoinTestFramework):
                           default=os.getenv("BITCOIND", "bitcoind"),
                           help="bitcoind binary to test")
 
-    def setup_chain(self):
-        initialize_chain_clean(self.options.tmpdir, 2)
+    def __init__(self):
+        super().__init__()
+        self.setup_clean_chain = True
+        self.num_nodes = 2
 
     def setup_network(self):
         # Node0 will be used to test behavior of processing unrequested blocks
diff --git a/qa/rpc-tests/p2p-feefilter.py b/qa/rpc-tests/p2p-feefilter.py
index 5fb51ed0fe..cd0501a314 100755
--- a/qa/rpc-tests/p2p-feefilter.py
+++ b/qa/rpc-tests/p2p-feefilter.py
@@ -46,6 +46,12 @@ class TestNode(SingleNodeConnCB):
         self.sync_with_ping()
 
 class FeeFilterTest(BitcoinTestFramework):
+
+    def __init__(self):
+        super().__init__()
+        self.num_nodes = 2
+        self.setup_clean_chain = False
+
     def setup_network(self):
         # Node1 will be used to generate txs which should be relayed from Node0
         # to our test node
diff --git a/qa/rpc-tests/p2p-fullblocktest.py b/qa/rpc-tests/p2p-fullblocktest.py
index 56df8ffd01..aa0501c5e9 100755
--- a/qa/rpc-tests/p2p-fullblocktest.py
+++ b/qa/rpc-tests/p2p-fullblocktest.py
@@ -29,6 +29,7 @@ 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__()
         self.num_nodes = 1
         self.block_heights = {}
         self.coinbase_key = CECKey()
diff --git a/qa/rpc-tests/p2p-versionbits-warning.py b/qa/rpc-tests/p2p-versionbits-warning.py
index 8c8c2358f7..962cafef0b 100755
--- a/qa/rpc-tests/p2p-versionbits-warning.py
+++ b/qa/rpc-tests/p2p-versionbits-warning.py
@@ -59,8 +59,10 @@ class TestNode(NodeConnCB):
 
 
 class VersionBitsWarningTest(BitcoinTestFramework):
-    def setup_chain(self):
-        initialize_chain_clean(self.options.tmpdir, 1)
+    def __init__(self):
+        super().__init__()
+        self.setup_clean_chain = True
+        self.num_nodes = 1
 
     def setup_network(self):
         self.nodes = []
diff --git a/qa/rpc-tests/prioritise_transaction.py b/qa/rpc-tests/prioritise_transaction.py
index 6ab88602b5..e1771231c0 100755
--- a/qa/rpc-tests/prioritise_transaction.py
+++ b/qa/rpc-tests/prioritise_transaction.py
@@ -14,11 +14,11 @@ from test_framework.mininode import COIN, MAX_BLOCK_SIZE
 class PrioritiseTransactionTest(BitcoinTestFramework):
 
     def __init__(self):
-        self.txouts = gen_return_txouts()
+        super().__init__()
+        self.setup_clean_chain = True
+        self.num_nodes = 1
 
-    def setup_chain(self):
-        print("Initializing test directory "+self.options.tmpdir)
-        initialize_chain_clean(self.options.tmpdir, 1)
+        self.txouts = gen_return_txouts()
 
     def setup_network(self):
         self.nodes = []
diff --git a/qa/rpc-tests/proxy_test.py b/qa/rpc-tests/proxy_test.py
index 6c7b201d56..27160cae07 100755
--- a/qa/rpc-tests/proxy_test.py
+++ b/qa/rpc-tests/proxy_test.py
@@ -36,6 +36,10 @@ addnode connect to generic DNS name
 
 class ProxyTest(BitcoinTestFramework):
     def __init__(self):
+        super().__init__()
+        self.num_nodes = 4
+        self.setup_clean_chain = False
+
         self.have_ipv6 = test_ipv6_local()
         # Create two proxies on different ports
         # ... one unauthenticated
@@ -77,7 +81,7 @@ class ProxyTest(BitcoinTestFramework):
             ]
         if self.have_ipv6:
             args[3] = ['-listen', '-debug=net', '-debug=proxy', '-proxy=[%s]:%i' % (self.conf3.addr),'-proxyrandomize=0', '-noonion']
-        return start_nodes(4, self.options.tmpdir, extra_args=args)
+        return start_nodes(self.num_nodes, self.options.tmpdir, extra_args=args)
 
     def node_test(self, node, proxies, auth, test_onion=True):
         rv = []
diff --git a/qa/rpc-tests/pruning.py b/qa/rpc-tests/pruning.py
index eac2272db2..d225e29b50 100755
--- a/qa/rpc-tests/pruning.py
+++ b/qa/rpc-tests/pruning.py
@@ -20,14 +20,14 @@ def calc_usage(blockdir):
 class PruneTest(BitcoinTestFramework):
 
     def __init__(self):
+        super().__init__()
+        self.setup_clean_chain = True
+        self.num_nodes = 3
+
         self.utxo = []
         self.address = ["",""]
         self.txouts = gen_return_txouts()
 
-    def setup_chain(self):
-        print("Initializing test directory "+self.options.tmpdir)
-        initialize_chain_clean(self.options.tmpdir, 3)
-
     def setup_network(self):
         self.nodes = []
         self.is_network_split = False
diff --git a/qa/rpc-tests/rawtransactions.py b/qa/rpc-tests/rawtransactions.py
index 7f7b6887a8..df02c1697f 100755
--- a/qa/rpc-tests/rawtransactions.py
+++ b/qa/rpc-tests/rawtransactions.py
@@ -14,12 +14,13 @@ from test_framework.util import *
 # Create one-input, one-output, no-fee transaction:
 class RawTransactionsTest(BitcoinTestFramework):
 
-    def setup_chain(self):
-        print("Initializing test directory "+self.options.tmpdir)
-        initialize_chain_clean(self.options.tmpdir, 3)
+    def __init__(self):
+        super().__init__()
+        self.setup_clean_chain = True
+        self.num_nodes = 3
 
     def setup_network(self, split=False):
-        self.nodes = start_nodes(3, self.options.tmpdir)
+        self.nodes = start_nodes(self.num_nodes, self.options.tmpdir)
 
         #connect to a local machine for debugging
         #url = "http://bitcoinrpc:DP6DvqZtqXarpeNWyN3LZTFchCCyCUuHwNF7E8pX99x1@%s:%d" % ('127.0.0.1', 18332)
diff --git a/qa/rpc-tests/receivedby.py b/qa/rpc-tests/receivedby.py
index a3f97669ea..4f17b661cb 100755
--- a/qa/rpc-tests/receivedby.py
+++ b/qa/rpc-tests/receivedby.py
@@ -27,10 +27,15 @@ def get_sub_array_from_array(object_array, to_match):
 
 class ReceivedByTest(BitcoinTestFramework):
 
+    def __init__(self):
+        super().__init__()
+        self.num_nodes = 4
+        self.setup_clean_chain = False
+
     def setup_nodes(self):
         #This test requires mocktime
         enable_mocktime()
-        return start_nodes(4, self.options.tmpdir)
+        return start_nodes(self.num_nodes, self.options.tmpdir)
 
     def run_test(self):
         '''
diff --git a/qa/rpc-tests/reindex.py b/qa/rpc-tests/reindex.py
index a3f4d6ea01..abbbb10336 100755
--- a/qa/rpc-tests/reindex.py
+++ b/qa/rpc-tests/reindex.py
@@ -12,9 +12,10 @@ import time
 
 class ReindexTest(BitcoinTestFramework):
 
-    def setup_chain(self):
-        print("Initializing test directory "+self.options.tmpdir)
-        initialize_chain_clean(self.options.tmpdir, 1)
+    def __init__(self):
+        super().__init__()
+        self.setup_clean_chain = True
+        self.num_nodes = 1
 
     def setup_network(self):
         self.nodes = []
diff --git a/qa/rpc-tests/replace-by-fee.py b/qa/rpc-tests/replace-by-fee.py
index 4afc3981da..34c0f9d795 100755
--- a/qa/rpc-tests/replace-by-fee.py
+++ b/qa/rpc-tests/replace-by-fee.py
@@ -68,6 +68,11 @@ def make_utxo(node, amount, confirmed=True, scriptPubKey=CScript([1])):
 
 class ReplaceByFeeTest(BitcoinTestFramework):
 
+    def __init__(self):
+        super().__init__()
+        self.num_nodes = 1
+        self.setup_clean_chain = False
+
     def setup_network(self):
         self.nodes = []
         self.nodes.append(start_node(0, self.options.tmpdir, ["-maxorphantx=1000", "-debug",
diff --git a/qa/rpc-tests/rest.py b/qa/rpc-tests/rest.py
index ec9515528e..c9c2eaf7f3 100755
--- a/qa/rpc-tests/rest.py
+++ b/qa/rpc-tests/rest.py
@@ -47,12 +47,13 @@ def http_post_call(host, port, path, requestdata = '', response_object = 0):
 class RESTTest (BitcoinTestFramework):
     FORMAT_SEPARATOR = "."
 
-    def setup_chain(self):
-        print("Initializing test directory "+self.options.tmpdir)
-        initialize_chain_clean(self.options.tmpdir, 3)
+    def __init__(self):
+        super().__init__()
+        self.setup_clean_chain = True
+        self.num_nodes = 3
 
     def setup_network(self, split=False):
-        self.nodes = start_nodes(3, self.options.tmpdir)
+        self.nodes = start_nodes(self.num_nodes, self.options.tmpdir)
         connect_nodes_bi(self.nodes,0,1)
         connect_nodes_bi(self.nodes,1,2)
         connect_nodes_bi(self.nodes,0,2)
diff --git a/qa/rpc-tests/rpcbind_test.py b/qa/rpc-tests/rpcbind_test.py
index 7b7c01f993..572273566b 100755
--- a/qa/rpc-tests/rpcbind_test.py
+++ b/qa/rpc-tests/rpcbind_test.py
@@ -24,7 +24,7 @@ def run_bind_test(tmpdir, allow_ips, connect_to, addresses, expected):
     if allow_ips:
         base_args += ['-rpcallowip=' + x for x in allow_ips]
     binds = ['-rpcbind='+addr for addr in addresses]
-    nodes = start_nodes(1, tmpdir, [base_args + binds], connect_to)
+    nodes = start_nodes(self.num_nodes, tmpdir, [base_args + binds], connect_to)
     try:
         pid = bitcoind_processes[0].pid
         assert_equal(set(get_bind_addrs(pid)), set(expected))
@@ -38,7 +38,7 @@ def run_allowip_test(tmpdir, allow_ips, rpchost, rpcport):
     at a non-localhost IP.
     '''
     base_args = ['-disablewallet', '-nolisten'] + ['-rpcallowip='+x for x in allow_ips]
-    nodes = start_nodes(1, tmpdir, [base_args])
+    nodes = start_nodes(self.num_nodes, tmpdir, [base_args])
     try:
         # connect to node through non-loopback interface
         url = "http://rt:rt@%s:%d" % (rpchost, rpcport,)
diff --git a/qa/rpc-tests/sendheaders.py b/qa/rpc-tests/sendheaders.py
index 96d1da729b..6ab17d59b3 100755
--- a/qa/rpc-tests/sendheaders.py
+++ b/qa/rpc-tests/sendheaders.py
@@ -208,12 +208,14 @@ class TestNode(BaseNode):
         BaseNode.__init__(self)
 
 class SendHeadersTest(BitcoinTestFramework):
-    def setup_chain(self):
-        initialize_chain_clean(self.options.tmpdir, 2)
+    def __init__(self):
+        super().__init__()
+        self.setup_clean_chain = True
+        self.num_nodes = 2
 
     def setup_network(self):
         self.nodes = []
-        self.nodes = start_nodes(2, self.options.tmpdir, [["-debug", "-logtimemicros=1"]]*2)
+        self.nodes = start_nodes(self.num_nodes, self.options.tmpdir, [["-debug", "-logtimemicros=1"]]*2)
         connect_nodes(self.nodes[0], 1)
 
     # mine count blocks and return the new tip
diff --git a/qa/rpc-tests/signmessages.py b/qa/rpc-tests/signmessages.py
index 4a47c0ca1e..31b6f14a26 100755
--- a/qa/rpc-tests/signmessages.py
+++ b/qa/rpc-tests/signmessages.py
@@ -10,12 +10,13 @@ from test_framework.util import *
 class SignMessagesTest(BitcoinTestFramework):
     """Tests RPC commands for signing and verifying messages."""
 
-    def setup_chain(self):
-        print('Initializing test directory ' + self.options.tmpdir)
-        initialize_chain_clean(self.options.tmpdir, 1)
+    def __init__(self):
+        super().__init__()
+        self.setup_clean_chain = True
+        self.num_nodes = 1
 
     def setup_network(self, split=False):
-        self.nodes = start_nodes(1, self.options.tmpdir)
+        self.nodes = start_nodes(self.num_nodes, self.options.tmpdir)
         self.is_network_split = False
 
     def run_test(self):
diff --git a/qa/rpc-tests/signrawtransactions.py b/qa/rpc-tests/signrawtransactions.py
index a06ac53191..c61a280616 100755
--- a/qa/rpc-tests/signrawtransactions.py
+++ b/qa/rpc-tests/signrawtransactions.py
@@ -10,12 +10,13 @@ from test_framework.util import *
 class SignRawTransactionsTest(BitcoinTestFramework):
     """Tests transaction signing via RPC command "signrawtransaction"."""
 
-    def setup_chain(self):
-        print('Initializing test directory ' + self.options.tmpdir)
-        initialize_chain_clean(self.options.tmpdir, 1)
+    def __init__(self):
+        super().__init__()
+        self.setup_clean_chain = True
+        self.num_nodes = 1
 
     def setup_network(self, split=False):
-        self.nodes = start_nodes(1, self.options.tmpdir)
+        self.nodes = start_nodes(self.num_nodes, self.options.tmpdir)
         self.is_network_split = False
 
     def successful_signing_test(self):
diff --git a/qa/rpc-tests/smartfees.py b/qa/rpc-tests/smartfees.py
index 8fcb99c1b7..d76fba4b07 100755
--- a/qa/rpc-tests/smartfees.py
+++ b/qa/rpc-tests/smartfees.py
@@ -145,6 +145,11 @@ def check_estimates(node, fees_seen, max_invalid, print_estimates = True):
 
 class EstimateFeeTest(BitcoinTestFramework):
 
+    def __init__(self):
+        super().__init__()
+        self.num_nodes = 3
+        self.setup_clean_chain = False
+
     def setup_network(self):
         '''
         We'll setup the network to have 3 nodes that all mine with different parameters.
diff --git a/qa/rpc-tests/test_framework/test_framework.py b/qa/rpc-tests/test_framework/test_framework.py
index 3480de6c6e..b9b803429d 100755
--- a/qa/rpc-tests/test_framework/test_framework.py
+++ b/qa/rpc-tests/test_framework/test_framework.py
@@ -15,7 +15,6 @@ import traceback
 
 from .util import (
     initialize_chain,
-    assert_equal,
     start_nodes,
     connect_nodes_bi,
     sync_blocks,
@@ -32,21 +31,26 @@ from .authproxy import JSONRPCException
 
 class BitcoinTestFramework(object):
 
-    # These may be over-ridden by subclasses:
+    def __init__(self):
+        self.num_nodes = 4
+        self.setup_clean_chain = False
+        self.nodes = None
+
     def run_test(self):
-        for node in self.nodes:
-            assert_equal(node.getblockcount(), 200)
-            assert_equal(node.getbalance(), 25*50)
+        raise NotImplementedError
 
     def add_options(self, parser):
         pass
 
     def setup_chain(self):
         print("Initializing test directory "+self.options.tmpdir)
-        initialize_chain(self.options.tmpdir)
+        if self.setup_clean_chain:
+            initialize_chain_clean(self.options.tmpdir, self.num_nodes)
+        else:
+            initialize_chain(self.options.tmpdir, self.num_nodes)
 
     def setup_nodes(self):
-        return start_nodes(4, self.options.tmpdir)
+        return start_nodes(self.num_nodes, self.options.tmpdir)
 
     def setup_network(self, split = False):
         self.nodes = self.setup_nodes()
@@ -181,9 +185,10 @@ class BitcoinTestFramework(object):
 
 class ComparisonTestFramework(BitcoinTestFramework):
 
-    # Can override the num_nodes variable to indicate how many nodes to run.
     def __init__(self):
+        super().__init__()
         self.num_nodes = 2
+        self.setup_clean_chain = True
 
     def add_options(self, parser):
         parser.add_option("--testbinary", dest="testbinary",
@@ -193,10 +198,6 @@ class ComparisonTestFramework(BitcoinTestFramework):
                           default=os.getenv("BITCOIND", "bitcoind"),
                           help="bitcoind binary to use for reference nodes (if any)")
 
-    def setup_chain(self):
-        print("Initializing test directory "+self.options.tmpdir)
-        initialize_chain_clean(self.options.tmpdir, self.num_nodes)
-
     def setup_network(self):
         self.nodes = start_nodes(
             self.num_nodes, self.options.tmpdir,
diff --git a/qa/rpc-tests/test_framework/util.py b/qa/rpc-tests/test_framework/util.py
index 6784177aaa..0e522e78d4 100644
--- a/qa/rpc-tests/test_framework/util.py
+++ b/qa/rpc-tests/test_framework/util.py
@@ -182,24 +182,28 @@ def wait_for_bitcoind_start(process, url, i):
                 raise # unkown JSON RPC exception
         time.sleep(0.25)
 
-def initialize_chain(test_dir):
+def initialize_chain(test_dir, num_nodes):
     """
-    Create (or copy from cache) a 200-block-long chain and
-    4 wallets.
+    Create a cache of a 200-block-long chain (with wallet) for MAX_NODES
+    Afterward, create num_nodes copies from the cache
     """
 
-    if (not os.path.isdir(os.path.join("cache","node0"))
-        or not os.path.isdir(os.path.join("cache","node1"))
-        or not os.path.isdir(os.path.join("cache","node2"))
-        or not os.path.isdir(os.path.join("cache","node3"))):
+    assert num_nodes <= MAX_NODES
+    create_cache = False
+    for i in range(MAX_NODES):
+        if not os.path.isdir(os.path.join('cache', 'node'+str(i))):
+            create_cache = True
+            break
+
+    if create_cache:
 
         #find and delete old cache directories if any exist
-        for i in range(4):
+        for i in range(MAX_NODES):
             if os.path.isdir(os.path.join("cache","node"+str(i))):
                 shutil.rmtree(os.path.join("cache","node"+str(i)))
 
         # Create cache directories, run bitcoinds:
-        for i in range(4):
+        for i in range(MAX_NODES):
             datadir=initialize_datadir("cache", i)
             args = [ os.getenv("BITCOIND", "bitcoind"), "-server", "-keypool=1", "-datadir="+datadir, "-discover=0" ]
             if i > 0:
@@ -212,15 +216,18 @@ def initialize_chain(test_dir):
                 print("initialize_chain: RPC succesfully started")
 
         rpcs = []
-        for i in range(4):
+        for i in range(MAX_NODES):
             try:
                 rpcs.append(get_rpc_proxy(rpc_url(i), i))
             except:
                 sys.stderr.write("Error connecting to "+url+"\n")
                 sys.exit(1)
 
-        # Create a 200-block-long chain; each of the 4 nodes
+        # Create a 200-block-long chain; each of the 4 first nodes
         # gets 25 mature blocks and 25 immature.
+        # Note: To preserve compatibility with older versions of
+        # initialize_chain, only 4 nodes will generate coins.
+        #
         # blocks are created with timestamps 10 minutes apart
         # starting from 2010 minutes in the past
         enable_mocktime()
@@ -238,13 +245,13 @@ def initialize_chain(test_dir):
         stop_nodes(rpcs)
         wait_bitcoinds()
         disable_mocktime()
-        for i in range(4):
+        for i in range(MAX_NODES):
             os.remove(log_filename("cache", i, "debug.log"))
             os.remove(log_filename("cache", i, "db.log"))
             os.remove(log_filename("cache", i, "peers.dat"))
             os.remove(log_filename("cache", i, "fee_estimates.dat"))
 
-    for i in range(4):
+    for i in range(num_nodes):
         from_dir = os.path.join("cache", "node"+str(i))
         to_dir = os.path.join(test_dir,  "node"+str(i))
         shutil.copytree(from_dir, to_dir)
diff --git a/qa/rpc-tests/txn_clone.py b/qa/rpc-tests/txn_clone.py
index 5710c29aa6..22f850ece6 100755
--- a/qa/rpc-tests/txn_clone.py
+++ b/qa/rpc-tests/txn_clone.py
@@ -12,6 +12,11 @@ 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/qa/rpc-tests/txn_doublespend.py b/qa/rpc-tests/txn_doublespend.py
index 1fbb207e22..84944c3c19 100755
--- a/qa/rpc-tests/txn_doublespend.py
+++ b/qa/rpc-tests/txn_doublespend.py
@@ -12,6 +12,11 @@ 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/qa/rpc-tests/wallet.py b/qa/rpc-tests/wallet.py
index f321f5e90b..9dda712f4f 100755
--- a/qa/rpc-tests/wallet.py
+++ b/qa/rpc-tests/wallet.py
@@ -19,9 +19,10 @@ class WalletTest (BitcoinTestFramework):
             raise AssertionError("Fee of %s BTC too high! (Should be %s BTC)"%(str(fee), str(target_fee)))
         return curr_balance
 
-    def setup_chain(self):
-        print("Initializing test directory "+self.options.tmpdir)
-        initialize_chain_clean(self.options.tmpdir, 4)
+    def __init__(self):
+        super().__init__()
+        self.setup_clean_chain = True
+        self.num_nodes = 4
 
     def setup_network(self, split=False):
         self.nodes = start_nodes(3, self.options.tmpdir)
diff --git a/qa/rpc-tests/walletbackup.py b/qa/rpc-tests/walletbackup.py
index c3d53669c9..b991d5c761 100755
--- a/qa/rpc-tests/walletbackup.py
+++ b/qa/rpc-tests/walletbackup.py
@@ -41,15 +41,16 @@ logging.basicConfig(format='%(levelname)s: %(message)s', level=logging.INFO, str
 
 class WalletBackupTest(BitcoinTestFramework):
 
-    def setup_chain(self):
-        logging.info("Initializing test directory "+self.options.tmpdir)
-        initialize_chain_clean(self.options.tmpdir, 4)
+    def __init__(self):
+        super().__init__()
+        self.setup_clean_chain = True
+        self.num_nodes = 4
 
     # This mirrors how the network was setup in the bash test
     def setup_network(self, split=False):
         # nodes 1, 2,3 are spenders, let's give them a keypool=100
         extra_args = [["-keypool=100"], ["-keypool=100"], ["-keypool=100"], []]
-        self.nodes = start_nodes(4, self.options.tmpdir, extra_args)
+        self.nodes = start_nodes(self.num_nodes, self.options.tmpdir, extra_args)
         connect_nodes(self.nodes[0], 3)
         connect_nodes(self.nodes[1], 3)
         connect_nodes(self.nodes[2], 3)
diff --git a/qa/rpc-tests/zapwallettxes.py b/qa/rpc-tests/zapwallettxes.py
index 2f8214f87c..17ba53a844 100755
--- a/qa/rpc-tests/zapwallettxes.py
+++ b/qa/rpc-tests/zapwallettxes.py
@@ -9,12 +9,13 @@ from test_framework.util import *
 
 class ZapWalletTXesTest (BitcoinTestFramework):
 
-    def setup_chain(self):
-        print("Initializing test directory "+self.options.tmpdir)
-        initialize_chain_clean(self.options.tmpdir, 3)
+    def __init__(self):
+        super().__init__()
+        self.setup_clean_chain = True
+        self.num_nodes = 3
 
     def setup_network(self, split=False):
-        self.nodes = start_nodes(3, self.options.tmpdir)
+        self.nodes = start_nodes(self.num_nodes, self.options.tmpdir)
         connect_nodes_bi(self.nodes,0,1)
         connect_nodes_bi(self.nodes,1,2)
         connect_nodes_bi(self.nodes,0,2)
diff --git a/qa/rpc-tests/zmq_test.py b/qa/rpc-tests/zmq_test.py
index f5617a084d..3a116317fe 100755
--- a/qa/rpc-tests/zmq_test.py
+++ b/qa/rpc-tests/zmq_test.py
@@ -17,6 +17,10 @@ import urllib.parse
 
 class ZMQTest (BitcoinTestFramework):
 
+    def __init__(self):
+        super().__init__()
+        self.num_nodes = 4
+
     port = 28332
 
     def setup_nodes(self):
@@ -25,7 +29,7 @@ class ZMQTest (BitcoinTestFramework):
         self.zmqSubSocket.setsockopt(zmq.SUBSCRIBE, b"hashblock")
         self.zmqSubSocket.setsockopt(zmq.SUBSCRIBE, b"hashtx")
         self.zmqSubSocket.connect("tcp://127.0.0.1:%i" % self.port)
-        return start_nodes(4, self.options.tmpdir, extra_args=[
+        return start_nodes(self.num_nodes, self.options.tmpdir, extra_args=[
             ['-zmqpubhashtx=tcp://127.0.0.1:'+str(self.port), '-zmqpubhashblock=tcp://127.0.0.1:'+str(self.port)],
             [],
             [],