diff --git a/tests/test_utils_opmsg.py b/tests/test_utils_opmsg.py
index 61af359d..a5d08b00 100644
--- a/tests/test_utils_opmsg.py
+++ b/tests/test_utils_opmsg.py
@@ -10,7 +10,6 @@ import time
 import threading
 import pytest
 from morbidissimo import MorIOC
-from slic.utils.opmsg import IDS, BEAMLINES, N_MSG_HISTORY
 
 def ioc():
     """
@@ -25,8 +24,8 @@ def ioc():
             mor.host(
                 STATUS={"type": "enum", "enums": ["OFFLINE", "PREPARATION", "REMOTE", "ATTENDED"]},
                 **{"STATUS-DATE": str},
-                **{f"OP-DATE{i}": str for i in range(N_MSG_HISTORY)},
-                **{f"OP-MSG{i}": str for i in range(N_MSG_HISTORY)},
+                **{f"OP-DATE{i}": str for i in range(3)},
+                **{f"OP-MSG{i}": str for i in range(3)},
                 **{"OP-MSG-TMP": str},
             )
 
@@ -34,8 +33,8 @@ def ioc():
             mor.serve(
                 STATUS="OFFLINE",
                 **{"STATUS-DATE": "2024-01-01 00:00:00"},
-                **{f"OP-DATE{i}": f"2024-01-01 00:00:0{i}" for i in range(N_MSG_HISTORY)},
-                **{f"OP-MSG{i}": f"Initial message {i}" for i in range(N_MSG_HISTORY)},
+                **{f"OP-DATE{i}": f"2024-01-01 00:00:0{i}" for i in range(3)},
+                **{f"OP-MSG{i}": f"Initial message {i}" for i in range(3)},
                 **{"OP-MSG-TMP": ""},
             )
 
@@ -71,7 +70,7 @@ def ioc():
 @pytest.fixture(scope="module", autouse=True)
 def run_all_iocs():
     threads = ioc()
-    time.sleep(0.5)
+    time.sleep(3.0)
     yield
 
 
@@ -289,9 +288,14 @@ class TestOperationMessages:
 
     def test_iter_yields_operationmessage_instances(self):
         oms = OperationMessages()
-        vals = list(iter(oms))
-        assert len(vals) == len(IDS)
-        assert all(isinstance(v, OperationMessage) for v in vals)
+        for om in oms:
+            _reset_operation_message_to_defaults(om)
+        
+        for om in oms:
+            assert om.status.status == "OFFLINE"
+            for i, entry in enumerate(om.entries):
+                assert entry.date == f"2024-01-01 00:00:{i}"
+                assert entry.msg == f"Initial message {i}"
 
         # All prefixes serve identical initial data; verify contents quickly
         for om in vals: