The thing that should be tested is whatever you are handing to a client app to use. If it is an interface, then test the interface, not the file behind it. If the client will get the file, then test that the file is correct.
So in this case, is this entire file being handed to clients to do what they will with it? Does that make sense as an interface.
If you are building an app, and you want other parts of the app, or clients of the app, to use this data, does it make sense to just hand over the entire file as the interface.
Basically :
Programmer 1: "Hey man, show me your data interface so I can build a quick lookup on something"
Programmer 2: "here is the whole damn file, do whatever you want and leave me alone. Figure it out yourself, and no I'm not going to give you a schema and I'll change it whenever I want".
So in this case, is this entire file being handed to clients to do what they will with it? Does that make sense as an interface.
If you are building an app, and you want other parts of the app, or clients of the app, to use this data, does it make sense to just hand over the entire file as the interface.
Basically :
Programmer 1: "Hey man, show me your data interface so I can build a quick lookup on something"
Programmer 2: "here is the whole damn file, do whatever you want and leave me alone. Figure it out yourself, and no I'm not going to give you a schema and I'll change it whenever I want".