SIENTIAPDE-1973

SIENTIAPDE-1973: Refactor unit tests for improved readability, primarily by splitting chained assertions into individual statements and minor fixture import adjustments.

tests/unit/conftest.py

@@ -1,13 +1,13 @@
 from unittest.mock import AsyncMock, MagicMock
 
-from pytest import fixture
+import pytest
 
 
-@fixture
+@pytest.fixture
 def reader_double():
     """Factory of OPC reader doubles holding subscriptions for the given slots.
 
-    Like the real readers (ServerReader, OpcManager), `subscriptions` is keyed by slot
+    Like the real ServerReader, `subscriptions` is keyed by slot
     and `unsubscribe` drops the slot from it.
     """