Allow tweaking underlying ganache's configuration

[spalladino]

We should allow tweaking ganache's configuration when running the tests. We currently only support block gas limit and accounts initial ETH, but we should also cover:

• EVM: to test how code will behave in a future fork (this includes upgrading the underlying ganache-core version)
• Forking: to support testing upgrades or other actions that would be run on mainnet
• Unlocked accounts: which allows using accounts without knowing their private key, in a forking scenario.
• Errors on RPC response: to test an app's behaviour upon reverts in a more realistic setting (noVMErrorsOnRPCResponse)
• Port: to have a consistent port in case the user wants to attach another process to ganache to monitor the transactions being run
• Blocktime: to check how the app behaves without instant seal

We can either do this by allowing the user to spin up their own ganache and attach to it (instead of using the one provided by test-env) or by adding more options to the configuration.

[frangio]

We should also support "unlocked accounts", which allows using accounts without knowing their private key. What I've heard is that they're useful when forking.

[spalladino]

Thanks Fran, added to the body of the issue!

[mds1]

Hey there, just curious what kind of timeline is expected for this issue? Really looking forward to using the OpenZeppelin Test Environment in my project, but am waiting for a few of these settings to be supported.

[spalladino]

Hey @mds1! Unfortunately this is not scheduled for the upcoming weeks, so I cannot give a precise answer. We would certainly welcome a PR with the feature if you are interested, though!

[mds1]

Got it, thanks. Probably won't get to it for a few weeks, but would be willing to take a shot at the PR then!

[abcoathup]

Request on the community forum for support testing on a forked ganache: https://forum.openzeppelin.com/t/testing-on-ganache-fork/2434

Also requested on Telegram: https://t.me/zeppelinos/10819

[frangio]

@knarz has submitted #55 enabling support for allowUnlimitedContractSize. Rather than adding ad-hoc suport for specific options I think we should add generic support for forwarding an object with arbitrary options. What does everyone think about this? I don't see this specifically mentioned in the comments above.

More specifically, I am proposing adding a field to our configuration file like:

module.exports = {
  accounts: {
    amount: 10, // Number of unlocked accounts
    ether: 100, // Initial balance of unlocked accounts (in ether)
  },

  node: {
    allowUnlimitedContractSize: true,
  },
};

where the object under node is forwarded as options to Ganache. I'm proposing node in case we introduce support for other nodes in the future (e.g. Geth) and the same option forwarding could take place. Alternatively we could just name it ganache for now.

There are some options we would not support, like custom account configuration. We would have to detect those and possibly throw an error or simply ignore them.

[ylv-io]

Agree with @frangio on the grouping. Accounts are also a part of Ganache/Node grouping because eventually Ethereum client is holding them.

[frangio]

I disagree with putting accounts inside the ganache/node object because there is a "preprocesing" step done by test-env. I would expect everything inside that object to be forwarded without any changes.