wallet_fallbackfee.py raw

   1  #!/usr/bin/env python3
   2  # Copyright (c) 2017-present The Bitcoin Core developers
   3  # Distributed under the MIT software license, see the accompanying
   4  # file COPYING or http://www.opensource.org/licenses/mit-license.php.
   5  """Test wallet fallbackfee."""
   6  
   7  from decimal import Decimal
   8  
   9  from test_framework.blocktools import COINBASE_MATURITY
  10  from test_framework.test_framework import BitcoinTestFramework
  11  from test_framework.util import assert_equal, assert_raises_rpc_error
  12  
  13  HIGH_TX_FEE_PER_KB = Decimal('0.01')
  14  
  15  
  16  class WalletFallbackFeeTest(BitcoinTestFramework):
  17      def set_test_params(self):
  18          self.num_nodes = 1
  19          self.setup_clean_chain = True
  20  
  21      def skip_test_if_missing_module(self):
  22          self.skip_if_no_wallet()
  23  
  24      def sending_succeeds(self, node):
  25          # Check that fallback fee is being used as a test-of-the-test.
  26          assert_equal(
  27              node.sendtoaddress(node.getnewaddress(), 1, verbose=True)['fee_reason'],
  28              "Fallback fee"
  29          )
  30          node.fundrawtransaction(node.createrawtransaction([], {node.getnewaddress(): 1}))
  31          assert_equal(
  32              node.sendmany("", {node.getnewaddress(): 1}, verbose=True)["fee_reason"],
  33              "Fallback fee"
  34          )
  35  
  36      def sending_fails(self, node):
  37          assert_raises_rpc_error(-6, "Fee estimation failed", lambda: node.sendtoaddress(node.getnewaddress(), 1))
  38          assert_raises_rpc_error(-4, "Fee estimation failed", lambda: node.fundrawtransaction(node.createrawtransaction([], {node.getnewaddress(): 1})))
  39          assert_raises_rpc_error(-6, "Fee estimation failed", lambda: node.sendmany("", {node.getnewaddress(): 1}))
  40  
  41      def run_test(self):
  42          node = self.nodes[0]
  43          self.generate(node, COINBASE_MATURITY + 1)
  44  
  45          # By default, the test framework sets a fallback fee for nodes,
  46          # in order to test default behavior, comment this line out.
  47          node.replace_in_config([("fallbackfee=", "#fallbackfee=")])
  48          self.restart_node(0)
  49  
  50          # Sending a transaction with no -fallbackfee setting fails, since the
  51          # default value is 0.
  52          self.sending_fails(node)
  53  
  54          # Sending a tx with explicitly disabled fallback fee fails.
  55          self.restart_node(0, extra_args=["-fallbackfee=0"])
  56          self.sending_fails(node)
  57  
  58          # Sending a transaction with a fallback fee set succeeds. Use the
  59          # largest fallbackfee value that doesn't trigger a warning.
  60          self.restart_node(0, extra_args=[f"-fallbackfee={HIGH_TX_FEE_PER_KB}"])
  61          self.sending_succeeds(node)
  62          self.stop_node(0, expected_stderr='')
  63  
  64          # Starting a node with a large fallback fee set...
  65          excessive_fallback = HIGH_TX_FEE_PER_KB + Decimal('0.00000001')
  66          self.start_node(0, extra_args=[f"-fallbackfee={excessive_fallback}"])
  67          # ...works...
  68          self.sending_succeeds(node)
  69          # ...but results in a warning message.
  70          expected_error = "Warning: -fallbackfee is set very high! This is the transaction fee you may pay when fee estimates are not available."
  71          self.stop_node(0, expected_stderr=expected_error)
  72  
  73  
  74  if __name__ == '__main__':
  75      WalletFallbackFeeTest(__file__).main()
  76