test: check testnet4 difficulty adjustment

test/functional/mining_testnet.py

@@ -0,0 +1,73 @@
+#!/usr/bin/env python3
+# Copyright (c) 2024 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+"""Test mining on testnet
+
+Test mining related RPCs that involve difficulty adjustment, which
+regtest doesn't have.
+
+It uses the first retarget period of testnet4, generated as follows:
+
+for i in {1..2015}
+do
+  hash=`bitcoin-cli -testnet4 getblockhash $i`
+  block=`bitcoin-cli -testnet4 getblock $hash 0`
+  echo $block >> data/testnet4.hex
+done
+"""
+
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.util import (
+    assert_equal,
+)
+from test_framework.blocktools import (
+    DIFF_1_N_BITS,
+    DIFF_1_TARGET,
+    DIFF_4_N_BITS,
+    DIFF_4_TARGET,
+    nbits_str,
+    target_str
+)
+
+import os
+
+class MiningTestnetTest(BitcoinTestFramework):
+
+    def set_test_params(self):
+        self.num_nodes = 1
+        self.setup_clean_chain = True
+        self.chain = "testnet4"
+
+    def add_options(self, parser):
+        parser.add_argument(
+            '--datafile',
+            default='data/testnet4.hex',
+            help='Test data file (default: %(default)s)',
+        )
+
+    def run_test(self):
+        node = self.nodes[0]
+        self.log.info("Load testnet4 blocks")
+        self.headers_file_path = os.path.join(os.path.dirname(os.path.realpath(__file__)), self.options.datafile)
+        with open(self.headers_file_path, encoding='utf-8') as blocks_data:
+            for block in blocks_data:
+                node.submitblock(block.strip())
+
+        assert_equal(node.getblockcount(), 2015)
+
+        mining_info = node.getmininginfo()
+        assert_equal(mining_info['difficulty'], 1)
+        assert_equal(mining_info['bits'], nbits_str(DIFF_1_N_BITS))
+        assert_equal(mining_info['target'], target_str(DIFF_1_TARGET))
+
+        assert_equal(mining_info['next']['height'], 2016)
+        assert_equal(mining_info['next']['difficulty'], 4)
+        assert_equal(mining_info['next']['bits'], nbits_str(DIFF_4_N_BITS))
+        assert_equal(mining_info['next']['target'], target_str(DIFF_4_TARGET))
+
+        assert_equal(node.getdifficulty(next=True), 4)
+        assert_equal(node.gettarget(next=True), target_str(DIFF_4_TARGET))
+
+if __name__ == '__main__':
+    MiningTestnetTest(__file__).main()

test/functional/test_framework/blocktools.py

@@ -70,6 +70,14 @@ REGTEST_N_BITS = 0x207fffff  # difficulty retargeting is disabled in REGTEST cha
 REGTEST_TARGET = 0x7fffff0000000000000000000000000000000000000000000000000000000000
 assert_equal(uint256_from_compact(REGTEST_N_BITS), REGTEST_TARGET)
 
+DIFF_1_N_BITS = 0x1d00ffff
+DIFF_1_TARGET = 0x00000000ffff0000000000000000000000000000000000000000000000000000
+assert_equal(uint256_from_compact(DIFF_1_N_BITS), DIFF_1_TARGET)
+
+DIFF_4_N_BITS = 0x1c3fffc0
+DIFF_4_TARGET = int(DIFF_1_TARGET / 4)
+assert_equal(uint256_from_compact(DIFF_4_N_BITS), DIFF_4_TARGET)
+
 def nbits_str(nbits):
     return f"{nbits:08x}"
 

test/functional/test_runner.py

@@ -316,6 +316,7 @@ BASE_SCRIPTS = [
     'wallet_upgradewallet.py --legacy-wallet',
     'wallet_crosschain.py',
     'mining_basic.py',
+    'mining_testnet.py',
     'feature_signet.py',
     'p2p_mutated_blocks.py',
     'wallet_implicitsegwit.py --legacy-wallet',