[英]How to unit test NSCoding?
I have an iOS application with data persisted using NSCoding and more precisely NSKeyedArchiver. 我有一个iOS应用程序,使用NSCoding持久化数据,更确切地说是NSKeyedArchiver。 This application is already available on the App Store.
此应用程序已在App Store上提供。
I'm working on version 2 of the application and the data model should change. 我正在研究应用程序的第2版,数据模型应该改变。 So I need to handle data model migration.
所以我需要处理数据模型迁移。 I want it covered by unit tests.
我希望它由单元测试覆盖。
In my tests, I want to dynamically generate persisted data with old data model, launch migration and see if everything went well. 在我的测试中,我想用旧数据模型动态生成持久化数据,启动迁移并查看是否一切顺利。
Currently, archiving an object looks like this : 目前,归档对象如下所示:
MyDataModelObject *object = ....
NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:data];
[archiver encodeObject:object forKey:key];
[archiver finishEncoding];
The problem is, MyDataModelObject might be re-factored or even deleted in the version 2 of the application. 问题是,MyDataModelObject可能会在应用程序的版本2中重新计算甚至删除。 So I can't use this class in my tests to generate an 'old version archive'.
所以我不能在我的测试中使用这个类来生成“旧版本档案”。
Is there a way to simulate what is done in the encodeWithCoder:
method of a class without using this class ? 有没有办法模拟在不使用这个类的类的
encodeWithCoder:
方法中完成的操作?
What I would like to achieve is the following 我想要实现的目标如下
- testMigrationFrom_v1_to_v2 {
// simulate an archive with v1 data model
// I want this part of the code to be as simple as possible
// I don't want to rely on old classes to generate the archive
NSDictionary *person = ... // { firstName: John, lastName: Doe }
NSDictionary *adress = ... // { street: 1 down street, city: Butterfly City }
[person setObject:adress forKey:@"adress"];
// there's something missing to tell the archiever that:
// - person is of type OldPersonDataModel
// - adress is of type OldAdressDataModel
[archiver encodeObject:person forKey:@"somePerson"];
// at this point, I would like the archive file to contain :
// a person object of type OldPersonDataModel, that has an adress object of type OldAdressModel
NewPersonModel *newPerson = [Migration readDataFromV1];
// assertions
NSAssert(newPerson.firstName, @"John");
NSAssert(newPerson.lastName, @"Doe");
}
I don't really understand your question so I will give you two answers: 我真的不明白你的问题所以我会给你两个答案:
You can preload an instance of NSDictionary
with keys/values you would use with your old class and just create a new keyed archiver, loop through all the keys and archive it. 您可以使用您在旧类中使用的键/值来预加载
NSDictionary
的实例,只需创建一个新的键控归档器,循环遍历所有键并将其归档。
You can also get any class's -attributeKeys
method to get all the keys and then possibly use this code to simulate an archive: 您还可以获取任何类的
-attributeKeys
方法来获取所有键,然后可能使用此代码来模拟存档:
NSKeyedArchiver *archive = [[NSKeyedArchiver alloc] initForWritingWithMutableData:data];
[archiver encodeObject:object forKey:key];
for (NSString *key in object.attributeKeys) {
[archive encodeObject:[object valueForKey:key] forKey:key];
}
[archive finishEncoding];
On the point of migrating data, NSKeyedArchiver has the method -setClass:forClassName:
and you can support all of your old keys in your new object to translate them into different properties. 在迁移数据时,NSKeyedArchiver具有方法
-setClass:forClassName:
并且您可以支持新对象中的所有旧键将它们转换为不同的属性。
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