diff --git a/apps/cic-eth/cic_eth/eth/erc20.py b/apps/cic-eth/cic_eth/eth/erc20.py
index 2c2685d3..080c0cea 100644
--- a/apps/cic-eth/cic_eth/eth/erc20.py
+++ b/apps/cic-eth/cic_eth/eth/erc20.py
@@ -526,9 +526,6 @@ def verify_token_info(self, tokens, chain_spec_dict, success_callback, error_cal
         s.link(success_callback)
         s.on_error(error_callback)
         s.apply_async()
-    #s_group.append(s)
-
-    #celery.group(s_group)()
 
     return tokens
 
diff --git a/apps/cic-eth/cic_eth/pytest/mock/callback.py b/apps/cic-eth/cic_eth/pytest/mock/callback.py
index d1d6fc4b..6825b208 100644
--- a/apps/cic-eth/cic_eth/pytest/mock/callback.py
+++ b/apps/cic-eth/cic_eth/pytest/mock/callback.py
@@ -1,4 +1,5 @@
 # standard imports
+import os
 import logging
 import mmap
 
@@ -13,21 +14,25 @@ logg = logging.getLogger()
 
 celery_app = celery.current_app
 
+
 class CallbackTask(celery.Task):
 
     mmap_path = tempfile.mkdtemp()
 
+
 @celery_app.task(bind=True, base=CallbackTask)
-def test_error_callback(self, a, b, c):
+def test_callback(self, a, b, c):
     s = 'ok'
     if c > 0:
         s = 'err'
 
     fp = os.path.join(self.mmap_path, b)
-    f = open(fp, 'wb')
-    m = mmap.mmap(f.fileno(), access=mmap.ACCESS_WRITE, length=1)
+    f = open(fp, 'wb+')
+    f.write(b'\x00')
+    f.seek(0)
+    m = mmap.mmap(f.fileno(), length=1)
     m.write(c.to_bytes(1, 'big'))
     m.close()
     f.close()
 
-    logg.debug('>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> test callback ({}): {} {} {} -> {}'.format(s, a, b, c, fp))
+    logg.debug('test callback ({}): {} {} {}'.format(s, a, b, c))
diff --git a/apps/cic-eth/tests/task/api/test_app_noncritical.py b/apps/cic-eth/tests/task/api/test_app_noncritical.py
index af42b79c..8df25479 100644
--- a/apps/cic-eth/tests/task/api/test_app_noncritical.py
+++ b/apps/cic-eth/tests/task/api/test_app_noncritical.py
@@ -3,6 +3,7 @@ import logging
 import os
 import uuid
 import time
+import mmap
 
 # external imports
 import celery
@@ -72,20 +73,48 @@ def test_tokens(
 
     celery_app = celery.current_app
 
+    results = []
+    targets = []
+
     api_param = str(uuid.uuid4())
-    api = Api(str(default_chain_spec), queue=None, callback_param=api_param, callback_task='cic_eth.pytest.mock.callback.test_error_callback')
+    api = Api(str(default_chain_spec), queue=None, callback_param=api_param, callback_task='cic_eth.pytest.mock.callback.test_callback')
     bogus_proof = os.urandom(32).hex()
     t = api.tokens(['FOO'], proof=[[bogus_proof]])
     r = t.get()
     logg.debug('r {}'.format(r))
-    time.sleep(0.1)
-    assert len(CallbackTask.errs[api_param]) == 1
-    assert CallbackTask.oks.get(api_param) == None
+
+    while True:
+        fp = os.path.join(CallbackTask.mmap_path, api_param)
+        try:
+            f = open(fp, 'rb')
+        except FileNotFoundError:
+            time.sleep(0.1)
+            logg.debug('look for {}'.format(fp))
+            continue
+        f = open(fp, 'rb')
+        m = mmap.mmap(f.fileno(), access=mmap.ACCESS_READ, length=1)
+        v = m.read(1)
+        m.close()
+        f.close()
+        assert v == b'\x01'
+        break
 
     api_param = str(uuid.uuid4())
-    api = Api(str(default_chain_spec), queue=None, callback_param=api_param, callback_task='cic_eth.pytest.mock.callback.test_error_callback')
+    api = Api(str(default_chain_spec), queue=None, callback_param=api_param, callback_task='cic_eth.pytest.mock.callback.test_callback')
     t = api.tokens(['BAR'], proof=[[bar_token_declaration]])
     r = t.get()
     logg.debug('rr  {} {}'.format(r, t.children))
-    time.sleep(0.1)
-    assert len(CallbackTask.oks[api_param]) == 1
+
+    while True:
+        fp = os.path.join(CallbackTask.mmap_path, api_param)
+        try:
+            f = open(fp, 'rb')
+        except FileNotFoundError:
+            time.sleep(0.1)
+            continue
+        m = mmap.mmap(f.fileno(), access=mmap.ACCESS_READ, length=1)
+        v = m.read(1)
+        m.close()
+        f.close()
+        assert v == b'\x00'
+        break