Setup single chain localnet for V2 contracts

[lumtis]

Implement a command

yarn localnet

That spins up a localnet environment on a single local evm chains. Both ZEVM and EVM contracts are deployed on a single local evm, the developers can interact with ZEVM and EVM gateways.

The cross-chain application can be simulated on a single network.

This would allow:

• Experimenting with new contracts much sooner before any work on the protocol.
• Use the environment to enable fuzz testing: https://github.com/zeta-chain/protocol-contracts/issues/180   The messages are relayed inside the single EVM chain.

Solutions to look for to relay the messages:

• A worker is spined up outside of the network and simulate observers/signers, it watches for the events and directly write to the counter party contract.
  • Need to develop this worker program but smart contracts are exactly the same
• We implement a modified version of the contracts (or contract inheriting existing ones) but that directly in the evm communicate with counter party contracts
  • Need new smart contracts but no offchain worker needed

[fadeev]

I like the worker idea.

[lumtis]

I might think solution 2 could be easier to implement if it works with inheritance, and would be more efficient for fuzz testing.

Now on the practice, I'm not 100% sure it can be implemented. If we need to develop whole other contracts, then workers might be better to simulate environment.

contract GatewayWithForwarding is Gateway

// ...

function call(...) overwrite {
  super.call()

  // call counterparty chain contract here
}