Remove StateClone

[DOBEN]

Purpose

closes #1039

Changes

• Remove StateClone

[Victor-N-Suadicani]

So as far as I gather, this was only used during unit tests? Ideally it should have been derived with cfg_attr(test, ...) (or does the derive macro do that?) but removing it is fine if it was only ever used this way I guess.

[DOBEN]

So as far as I gather, this was only used during unit tests? Ideally it should have been derived with cfg_attr(test, ...) (or does the derive macro do that?) but removing it is fine if it was only ever used this way I guess.

We used to have different macros (such as StateClone) that allowed the use of the contract state in the real blockchain environment as well as in a mocked-up environment (using the cargo unit test infrastructure). These abstractions were quite cumbersome and it was hard to mock all smart contract interactions realistically hence we built the integration testing library framework that is used nowadays.

Since the unit testing infrastructure has been deprecated for a while now, I do not fully remember all its details, so it is hard to discuss whether it should have been implemented otherwise or not. But I would expect that if we compile the smart contract for the actual deployment on-chain unnecessary testing abstractions/code would be removed in the past.