diff --git a/qa/rpc-tests/lockzins.py b/qa/rpc-tests/lockzins.py
index 6fe6cf4bd..232667ab5 100755
--- a/qa/rpc-tests/lockzins.py
+++ b/qa/rpc-tests/lockzins.py
@@ -7,7 +7,8 @@ from test_framework.test_framework import BitcoinTestFramework
 from test_framework.authproxy import JSONRPCException
 from test_framework.util import assert_equal, assert_greater_than, \
     initialize_chain_clean, initialize_chain, start_nodes, start_node, connect_nodes_bi, \
-    stop_nodes, sync_blocks, sync_mempools, wait_bitcoinds, rpc_port, assert_raises, assert_true
+    stop_nodes, sync_blocks, sync_mempools, wait_bitcoinds, rpc_port, assert_raises, assert_true, \
+    wait_and_assert_operationid_status
 
 import time
 from decimal import Decimal
@@ -38,11 +39,11 @@ class LockZinsTest (BitcoinTestFramework):
                     '-conf='+self.options.tmpdir+'/node0/regtest/ZZZ.conf',
                     '-port=64367',
                     '-rpcport=64368',
-                    '-ac_supply=10',
-                    '-ac_reward=25600000000',
+                    '-ac_supply=1',
+                    '-ac_reward=100000000',
                     '-ac_private=1',
                     '-allowlist=127.0.0.1',
-                    '-debug',
+                    #'-debug',
                     '-regtest',
                     '--daemon',
                     #'-rpcuser=hush',
@@ -57,22 +58,47 @@ class LockZinsTest (BitcoinTestFramework):
     def run_test (self):
         print("Mining blocks...")
         rpc     = self.nodes[0]
-        # mine the initial ac_supply
-        rpc.generate(5)
-        self.sync_all()
-
-        zaddr = rpc.z_getnewaddress()
-        print("Created zaddr %s" % zaddr)
-
-        rpc.getinfo()
-        time.sleep(1)
-        rpc.getinfo()
-
-        rpc.z_shieldcoinbase('*', zaddr)
+        # mine initial ac_supply
         rpc.generate(1)
-
         self.sync_all()
-        print(rpc.z_getbalances())
+
+        zaddr1 = rpc.z_getnewaddress()
+        zaddr2 = rpc.z_getnewaddress()
+
+        x = 0
+        while x < 15:
+            rpc.generate(1)
+            self.sync_all()
+            time.sleep(1)
+            rpc.z_shieldcoinbase('*', zaddr1, 0, 1)
+            x = x+1
+
+        rpc.generate(11)
+        self.sync_all()
+        rpc.z_listunspent()
+        rpc.z_getbalances()
+
+        recipients = []
+        recipients.append({"address": zaddr2, "amount": Decimal('3')})
+
+        # queue 4 ztxs, which will try to spend the same funds multiple times
+        # without correct locking of zins
+        opid1 = rpc.z_sendmany(zaddr1,recipients,1,0)
+        opid2 = rpc.z_sendmany(zaddr1,recipients,1,0)
+        opid3 = rpc.z_sendmany(zaddr1,recipients,1,0)
+        opid4 = rpc.z_sendmany(zaddr1,recipients,1,0)
+
+        rpc.generate(1)
+        self.sync_all()
+        wait_and_assert_operationid_status(self.nodes[0], opid1)
+        wait_and_assert_operationid_status(self.nodes[0], opid2)
+        wait_and_assert_operationid_status(self.nodes[0], opid3)
+        wait_and_assert_operationid_status(self.nodes[0], opid4)
+
+        # give time for all z_sendmany's to run
+        #time.sleep(10)
+
+        rpc.z_getoperationstatus()
 
 if __name__ == '__main__':
     LockZinsTest ().main()
diff --git a/qa/rpc-tests/test_framework/util.py b/qa/rpc-tests/test_framework/util.py
index 9e71a28f0..ff1115b88 100644
--- a/qa/rpc-tests/test_framework/util.py
+++ b/qa/rpc-tests/test_framework/util.py
@@ -103,6 +103,7 @@ def initialize_datadir(dirname, n):
     with open(os.path.join(datadir, "ZZZ.conf"), 'w') as f:
         f.write("regtest=1\n");
         f.write("txindex=1\n");
+        #f.write("testnode=1\n");
         f.write("server=1\n");
         f.write("showmetrics=0\n");
         f.write("rpcuser=hush\n");
@@ -481,7 +482,7 @@ def assert_raises(exc, fun, *args, **kwds):
 def wait_and_assert_operationid_status(node, myopid, in_status='success', in_errormsg=None, timeout=300):
     print('waiting for async operation {}'.format(myopid))
     result = None
-    for _ in xrange(1, timeout):
+    for _ in range(1, timeout):
         results = node.z_getoperationresult([myopid])
         if len(results) > 0:
             result = results[0]