[fees] introduce configurable hard dust limit

Co-authored-by: Ross Nicoll <[email protected]>

2 files changed, 83 insertions, 0 deletions

diff --git a/qa/pull-tester/rpc-tests.py b/qa/pull-tester/rpc-tests.py
index f7a2deb0d..fd78d3701 100755
--- a/qa/pull-tester/rpc-tests.py
+++ b/qa/pull-tester/rpc-tests.py
@@ -153,6 +153,7 @@ testScripts = [
     'signmessages.py',
     # 'nulldummy.py',
     'import-rescan.py',
+    'harddustlimit.py',
     # While fee bumping should work in Doge, these tests depend on free transactions, which we don't support.
     # Disable until we can do a full rewrite of the tests (possibly upstream), or revise fee schedule, or something
     'bumpfee.py',
diff --git a/qa/rpc-tests/harddustlimit.py b/qa/rpc-tests/harddustlimit.py
new file mode 100644
index 000000000..9d56febb7
--- /dev/null
+++ b/qa/rpc-tests/harddustlimit.py
@@ -0,0 +1,82 @@
+#!/usr/bin/env python3
+# Copyright (c) 2021 The Dogecoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+"""Hard dust limit QA test.
+
+# Tests nodes with differing -dustlimits
+"""
+
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.util import *
+from decimal import Decimal
+
+class HardDustLimitTest(BitcoinTestFramework):
+
+    def __init__(self):
+        super().__init__()
+        self.setup_clean_chain = True
+        self.num_nodes = 3
+
+    def setup_network(self, split=False):
+        self.nodes = []
+        self.nodes.append(start_node(0, self.options.tmpdir, ["-dustlimit=0.1", "-debug"]))
+        self.nodes.append(start_node(1, self.options.tmpdir, ["-dustlimit=1", "-debug"]))
+        self.nodes.append(start_node(2, self.options.tmpdir, ["-dustlimit=0.01", "-debug"]))
+
+        connect_nodes_bi(self.nodes,0,1)
+        connect_nodes_bi(self.nodes,1,2)
+        connect_nodes_bi(self.nodes,0,2)
+
+        self.is_network_split=False
+        self.sync_all()
+
+    def run_test(self):
+
+        self.fee = Decimal("1")
+        self.seed = 1000
+        self.coinselector = {'minimumAmount': self.fee * 10, 'maximumAmount': self.seed}
+
+        # set up addresses
+        n0a1 = self.nodes[0].getnewaddress()
+        n0a2 = self.nodes[0].getnewaddress()
+        n0a3 = self.nodes[0].getnewaddress()
+        n1a1 = self.nodes[1].getnewaddress()
+        n2a1 = self.nodes[2].getnewaddress()
+        n2a2 = self.nodes[2].getnewaddress()
+        n2a3 = self.nodes[2].getnewaddress()
+        n2a4 = self.nodes[2].getnewaddress()
+
+        # mine some blocks and prepare some coins
+        self.nodes[2].generate(1)
+        self.sync_all()
+        self.nodes[0].generate(101)
+        self.sync_all()
+        self.nodes[0].sendtoaddress(n0a1, self.seed)
+        self.nodes[0].sendtoaddress(n2a1, self.seed)
+        self.sync_all()
+        self.nodes[0].generate(1)
+        self.sync_all()
+
+        # create dusty transactions
+        self.send_dusty_tx(self.nodes[2], n2a2, n0a2, Decimal("0.9"))
+        self.send_dusty_tx(self.nodes[2], n2a3, n0a3, Decimal("0.09"))
+        self.send_dusty_tx(self.nodes[0], n2a4, n1a1, Decimal("1"))
+
+        # wait 10 seconds to sync mempools
+        time.sleep(10)
+
+        assert_equal(self.nodes[2].getmempoolinfo()['size'], 3)
+        assert_equal(self.nodes[1].getmempoolinfo()['size'], 1)
+        assert_equal(self.nodes[0].getmempoolinfo()['size'], 2)
+
+    def send_dusty_tx(self, n, addr1, addr2, dust):
+        avail = n.listunspent(0, 1000, [], True, self.coinselector)
+        inputs = [ {'txid': avail[0]['txid'], 'vout': avail[0]['vout']}]
+        outputs = { addr1 : avail[0]['amount'] - self.fee - dust , addr2: dust }
+        rawtx = n.createrawtransaction(inputs, outputs)
+        rawtx = n.signrawtransaction(rawtx)
+        n.sendrawtransaction(rawtx['hex'])
+
+if __name__ == '__main__':
+    HardDustLimitTest().main()