test: Fix intermittent sync_blocks failures

test/functional/wallet_basic.py

@@ -4,7 +4,6 @@
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """Test the wallet."""
 from decimal import Decimal
-import time
 
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import (
@@ -466,12 +465,8 @@ class WalletTest(BitcoinTestFramework):
         extra_args = ["-walletrejectlongchains", "-limitancestorcount=" + str(2 * chainlimit)]
         self.start_node(0, extra_args=extra_args)
 
-        # wait for loadmempool
-        timeout = 10
-        while (timeout > 0 and len(self.nodes[0].getrawmempool()) < chainlimit * 2):
-            time.sleep(0.5)
-            timeout -= 0.5
-        assert_equal(len(self.nodes[0].getrawmempool()), chainlimit * 2)
+        # wait until the wallet has submitted all transactions to the mempool
+        wait_until(lambda: len(self.nodes[0].getrawmempool()) == chainlimit * 2)
 
         node0_balance = self.nodes[0].getbalance()
         # With walletrejectlongchains we will not create the tx and store it in our wallet.