sudden Code review

tests/core/test_foreach_barrier_state.py

@@ -64,3 +64,43 @@ def test_foreach_barrier_state_rejects_malformed_metadata() -> None:
 
     with pytest.raises(WorkflowExecutionError, match="next_index"):
         ForeachBarrierState.from_frame(frame, "each")
+
+
+def test_item_error_record_rejects_negative_index() -> None:
+    with pytest.raises(WorkflowExecutionError, match="index"):
+        ItemErrorRecord.from_metadata(
+            {
+                "index": -1,
+                "frame_id": "child",
+                "node_id": "work",
+                "error_type": "ValueError",
+                "message": "bad",
+            }
+        )
+
+
+def test_pending_item_result_reports_missing_required_field() -> None:
+    with pytest.raises(WorkflowExecutionError, match="missing 'frame_id'"):
+        PendingItemResult.from_metadata({"index": 0, "status": "succeeded"})
+
+
+def test_pending_item_result_rejects_negative_index() -> None:
+    with pytest.raises(WorkflowExecutionError, match="index"):
+        PendingItemResult.from_metadata(
+            {"index": -1, "frame_id": "child", "status": "succeeded"}
+        )
+
+
+def test_save_to_frame_rejects_corrupt_table_without_mutating() -> None:
+    frame = ExecutionFrame(
+        id="root",
+        kind="root",
+        node_id="each",
+        metadata={"foreach_barriers": "corrupt"},
+    )
+    barrier = ForeachBarrierState(next_index=1)
+
+    with pytest.raises(WorkflowExecutionError, match="barrier table"):
+        barrier.save_to_frame(frame, "each")
+
+    assert frame.metadata["foreach_barriers"] == "corrupt"

tests/core/test_scheduler.py

@@ -96,6 +96,14 @@ def test_blocked_frame_is_not_selectable_until_woken() -> None:
     assert selected.id == "parent"
 
 
+def test_block_frame_on_children_rejects_empty_child_set() -> None:
+    run = _run()
+    add_frame(run, ExecutionFrame(id="parent", kind="root", node_id="foreach"))
+
+    with pytest.raises(WorkflowExecutionError, match="empty child set"):
+        block_frame_on_children(run, "parent", ())
+
+
 def test_create_run_state_queues_root_frame() -> None:
     workflow = Workflow(
         name="demo",