Use COINBASE_MATURITY constant in functional tests.

test/functional/wallet_groups.py

@@ -4,6 +4,7 @@
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """Test wallet group functionality."""
 
+from test_framework.blocktools import COINBASE_MATURITY
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.messages import CTransaction, FromHex, ToHex
 from test_framework.util import (
@@ -31,7 +32,7 @@ class WalletGroupTest(BitcoinTestFramework):
     def run_test(self):
         self.log.info("Setting up")
         # Mine some coins
-        self.nodes[0].generate(101)
+        self.nodes[0].generate(COINBASE_MATURITY + 1)
 
         # Get some addresses from the two nodes
         addr1 = [self.nodes[1].getnewaddress() for _ in range(3)]