test: Start only the number of nodes that are needed

test/functional/wallet_txn_doublespend.py

@@ -11,9 +11,10 @@ from test_framework.util import (
     find_output,
 )
 
+
 class TxnMallTest(BitcoinTestFramework):
     def set_test_params(self):
-        self.num_nodes = 4
+        self.num_nodes = 3
         self.supports_cli = False
 
     def skip_test_if_missing_module(self):
@@ -39,7 +40,7 @@ class TxnMallTest(BitcoinTestFramework):
         for n in self.nodes:
             assert n.getblockchaininfo()["initialblockdownload"] == False
 
-        for i in range(4):
+        for i in range(3):
             assert_equal(self.nodes[i].getbalance(), starting_balance)
             self.nodes[i].getnewaddress("")  # bug workaround, coins generated assigned to first getnewaddress!
 
@@ -136,5 +137,6 @@ class TxnMallTest(BitcoinTestFramework):
         # Node1's balance should be its initial balance (1250 for 25 block rewards) plus the doublespend:
         assert_equal(self.nodes[1].getbalance(), 1250 + 1240)
 
+
 if __name__ == '__main__':
     TxnMallTest().main()