Improve test coverage for op module based on review feedback (#29)

* Initial plan

* Add tests for _execute_operation with provided session and read_with_poll without vt

Co-authored-by: jason810496 <[email protected]>

* Add test for async _execute_operation path when session is None

Co-authored-by: jason810496 <[email protected]>

* Remove fragile line number references from test comments

Co-authored-by: jason810496 <[email protected]>

* Clarify comment in test_read_with_poll_without_vt

Co-authored-by: jason810496 <[email protected]>

* Address final code review feedback: improve test structure and add cleanup verification

Co-authored-by: jason810496 <[email protected]>

---------

Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: jason810496 <[email protected]>

Author: Copilot

tests/test_queue.py

@@ -480,3 +480,89 @@ def test_create_partitioned_queue_invalid_numeric_interval(pgmq_all_variants):
             queue_name, partition_interval=-100, retention_interval=100000
         )
     assert "Numeric partition interval must be positive" in str(e.value)
+
+
+def test_read_with_poll_without_vt(pgmq_setup_teardown: PGMQ_WITH_QUEUE):
+    """Test read_with_poll when vt parameter is not provided (None)."""
+
+    pgmq, queue_name = pgmq_setup_teardown
+    
+    # Set a custom default vt for the pgmq instance
+    pgmq.vt = 100
+    
+    # Send a message
+    msg_id = pgmq.send(queue_name, MSG)
+    
+    # Call read_with_poll with vt=None to test the fallback logic
+    # When vt is None, it should fall back to using pgmq.vt value (100)
+    msgs = pgmq.read_with_poll(
+        queue_name,
+        vt=None,  # Explicitly passing None to test the None fallback logic
+        qty=1,
+        max_poll_seconds=2,
+        poll_interval_ms=100,
+    )
+    
+    assert msgs is not None
+    assert len(msgs) == 1
+    assert msgs[0].msg_id == msg_id
+    assert msgs[0].message == MSG
+
+
+def test_execute_operation_with_provided_sync_session(pgmq_by_session_maker, get_session_maker, db_session):
+    """Test _execute_operation sync path when session is provided."""
+
+    pgmq: PGMQueue = pgmq_by_session_maker
+    queue_name = f"test_queue_{uuid.uuid4().hex}"
+    
+    # Create a session to pass to the operations
+    # Using the same session across multiple operations demonstrates
+    # that the sync path with provided session works correctly
+    with get_session_maker() as session:
+        # Create queue with provided session
+        pgmq.create_queue(queue_name, session=session)
+        
+        # Verify queue was created
+        assert check_queue_exists(db_session, queue_name) is True
+        
+        # Send a message with the same provided session
+        msg_id = pgmq.send(queue_name, MSG, session=session)
+        
+        # Read message with the same provided session
+        msg = pgmq.read(queue_name, vt=30, session=session)
+        
+        assert msg is not None
+        assert msg.msg_id == msg_id
+        assert msg.message == MSG
+        
+        # Clean up with the same provided session
+        pgmq.drop_queue(queue_name, session=session)
+    
+    # Verify queue was dropped
+    assert check_queue_exists(db_session, queue_name) is False
+
+
+def test_execute_operation_async_with_session_none(pgmq_by_async_dsn, db_session):
+    """Test _execute_operation async path when session is None."""
+
+    pgmq: PGMQueue = pgmq_by_async_dsn
+    queue_name = f"test_queue_{uuid.uuid4().hex}"
+    
+    # Verify this is an async PGMQueue
+    assert pgmq.is_async is True
+    
+    # When session is None, _execute_operation creates a new async session
+    # and uses loop.run_until_complete to execute the operation
+    pgmq.create_queue(queue_name)
+    msg_id = pgmq.send(queue_name, MSG)
+    msg = pgmq.read(queue_name, vt=30)
+    
+    assert msg is not None
+    assert msg.msg_id == msg_id
+    assert msg.message == MSG
+    
+    # Clean up
+    pgmq.drop_queue(queue_name)
+    
+    # Verify queue was dropped
+    assert check_queue_exists(db_session, queue_name) is False