修正单元测试失败代码

app/native/wndb/database.py

@@ -136,18 +136,20 @@ def execute_undo(name: str, discard: bool = False) -> ChangeSet:
 
     write(name, row['undo'])
 
+    parent = row['parent'] if row['parent'] != None else 0
+
     # update foreign key
-    write(name, f"update current_operation set id = {row['parent']} where id = {row['id']}")
+    write(name, f"update current_operation set id = {parent} where id = {row['id']}")
 
     if discard:
         # update foreign key
-        write(name, f"update operation set redo_child = null where id = {row['parent']}")
+        write(name, f"update operation set redo_child = null where id = {parent}")
         # on delete cascade => child & snapshot
         write(name, f"delete from operation where id = {row['id']}")
     else:
-        write(name, f"update operation set redo_child = {row['id']} where id = {row['parent']}")
+        write(name, f"update operation set redo_child = {row['id']} where id = {parent}")
 
-    e = eval(row['undo_cs'])
+    e = eval(row['undo_cs']) if row['undo_cs'] not in [None, ''] else []
     return ChangeSet.from_list(e)
 
 
@@ -159,9 +161,10 @@ def execute_redo(name: str) -> ChangeSet:
     row = read(name, f"select * from operation where id = {row['redo_child']}")
     write(name, row['redo'])
 
-    write(name, f"update current_operation set id = {row['id']} where id = {row['parent']}")
+    parent = row['parent'] if row['parent'] != None else 0
+    write(name, f"update current_operation set id = {row['id']} where id = {parent}")
 
-    e = eval(row['redo_cs'])
+    e = eval(row['redo_cs']) if row['redo_cs'] not in [None, ''] else []
     return ChangeSet.from_list(e)