Implement scantxoutset method and test

[GideonBature]

The JSON-RPC method scantxoutset does return a type. We want to test this to catch any changes in behavior in future Core versions.

This PR adds a client function that errors if the return value is anything other than the type it returns, along with an integration test that calls this function.

Ref: #116
Closes #115

[tcharding]

Why is there identical code in the v17 and v18 blockchain modules of the client?

[GideonBature]

Why is there identical code in the v17 and v18 blockchain modules of the client?

They basically work the same way, the difference is in their return type, v18 has an additional field (desc) in it's result, whereas it is lacking in v17. Or is there a way to reuse the client code in v17 for v18 and still be able to return the type that is meant for v18?

[tcharding]

Bro I explained this to you already on the other two PRs you did. Perhaps go back over them and see if you can work it out.

[GideonBature]

Bro I explained this to you already on the other two PRs you did. Perhaps go back over them and see if you can work it out.

oh, I now understand, I was looking at how gettxout was used in the client, where despite the code is similar, they used it for v17 and again for v22. So I thought that for any change in the fields of return type of a method, there should also be a code in the module of the client for that particular version with the change. But I can see that it's not always the case.

For this recent push, I removed the repeated code across all versions having different fields in their type.

[tcharding]

Oh well that would explain your confusion, the gettxout in v22 is just plain wrong. I'll remove it.

[tcharding]

Done in #169. FTR bugs happen, if you see things that are wrong or look weird just ask (or PR to fix them). Apologies for being so fierce yesterday.

[tcharding]

Returns column needs updating (and Notes).

[tcharding]

Holy moly you picked a difficult one. I'm going to have to come back to this when I can put more thought into it. Feel free to ignore my suggestions until then.

[tcharding]

Oh this is interesting. This is a new idea for the crate, it could be done for all the methods that have verbose results. I'm not sure it adds any value though. I'd just remove this and leave the three individual return types. Plus I'd document 'returned when the foo action as taken'.

[tcharding]

after looking at v28 I'm not sure - leave it with me for a bit.

[GideonBature]

Alright... Noted. That would be great using it for the methods having verbose results.

[GideonBature]

Done in #169. FTR bugs happen, if you see things that are wrong or look weird just ask (or PR to fix them). Apologies for being so fierce yesterday.

No problem. I will do this going forward.

[GideonBature]

Returns column needs updating (and Notes).

Noted!

[GideonBature]

Holy moly you picked a difficult one. I'm going to have to come back to this when I can put more thought into it. Feel free to ignore my suggestions until then.

Noted....

[GideonBature]

Returns column needs updating (and Notes).

for the notes, is there any need to change it? since it describes perfectly that the scantxoutset is experimental.

[tcharding]

Oh you are right, lets leave the notes as they are.

[tcharding]

Man this method is really not that simple to add support for because it changes so often. Can we put this one on hold until you've got a few more easy ones done?

[GideonBature]

Man this method is really not that simple to add support for because it changes so often. Can we put this one on hold until you've got a few more easy ones done?

Understood... sure, let's do that.