tidy up old code

tests/node_tests/print_table.py

@@ -1,5 +1,6 @@
 def test_print_table():
     from backend.nodes.print_table import PrintTable
+    from backend.execution_context import execution_callbacks, active_node
     node = PrintTable()
 
     table_spec = PrintTable.INPUT_TYPES()["required"]["table"]
@@ -7,12 +8,8 @@ def test_print_table():
     assert table_spec[1]["accepted_types"] == ["DATA_TABLE"]
 
     captured = []
-    PrintTable._broadcast_table_fn = lambda node_id, rows: captured.append(rows)
-    PrintTable._current_node_id = "test"
-
-    table = [{"quantity": "test", "value": 42.0, "unit": "m"}]
-    node.print_table(table=table)
-    assert len(captured) == 1
-    assert captured[0] == table
-
-    PrintTable._broadcast_table_fn = None
+    with execution_callbacks(table=lambda nid, rows: captured.append(rows)), active_node("test"):
+        table = [{"quantity": "test", "value": 42.0, "unit": "m"}]
+        node.print_table(table=table)
+        assert len(captured) == 1
+        assert captured[0] == table