Test using Core's test cases

[tcharding]

Currently we have only limited test coverage. And for the RPC methods that are tested we only test a subset of things e.g.,

• We don't test all optional fields
• We don't ensure all fields are non-default e.g., they may be being filled in by serde and not actually deserialized.

An idea, courtesy of @stevenroose, is to grab the tests from Core used for testing the RPC code and then try to parse all of those.

[GideonBature]

The idea is great, as it will help us ensure that:

• most if not all optional fields are tested.
• prevents issues where fields might not be correctly deserialised but still seem to work due to default values.
• we will be certain that it follows correctly Bitcoin Core's RPC Specification.

We can Start the implementation, I will be like to take on the task if it's okay.

[tcharding]

Go wild.