Hello. First of all, great package!
It really reduces boilerplate code in tests and makes everything more readable.

I have a feature request/consideration I hope would get included to this project and I may help implement it if that's something that makes sense for this library: Partial JSON matching.

It can be behind a flag or in another method, but it basically means a JSON with 4 properties, when checked against a JSON with 2 properties, would not return the following error:

expected 2 keys at '$' but got 4 keys
unexpected object key(s) ["status","cause"] found at '$'

More often than not, we need to check for the overall structure and main fields and not the whole thing, and having to check for presence of every single field can take a lot of time.

Is this something that makes sense for you as the author of this library?
As much as I like creating my own fork, I think it's best for the community if we keep things centralized.

Thanks.