Move COINBASE_MATURITY from feature_nulldummy test to blocktools.

Author: kiminuo

test/functional/feature_nulldummy.py

@@ -14,13 +14,18 @@
 """
 import time
 
-from test_framework.blocktools import NORMAL_GBT_REQUEST_PARAMS, create_block, create_transaction, add_witness_commitment
+from test_framework.blocktools import (
+    COINBASE_MATURITY,
+    NORMAL_GBT_REQUEST_PARAMS,
+    add_witness_commitment,
+    create_block,
+    create_transaction,
+)
 from test_framework.messages import CTransaction
 from test_framework.script import CScript
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import assert_equal, assert_raises_rpc_error
 
-COINBASE_MATURITY = 100
 NULLDUMMY_ERROR = "non-mandatory-script-verify-flag (Dummy CHECKMULTISIG argument must be zero)"
 
 def trueDummy(tx):

test/functional/test_framework/blocktools.py

@@ -52,6 +52,9 @@
 # Genesis block time (regtest)
 TIME_GENESIS_BLOCK = 1296688602
 
+# Coinbase transaction outputs can only be spent after this number of new blocks (network rule)
+COINBASE_MATURITY = 100
+
 # From BIP141
 WITNESS_COMMITMENT_HEADER = b"\xaa\x21\xa9\xed"