Testing on forked chains

[Alderian]

Problem:

• Current TestHelper creates various endpoints, but the are all created on the same network
• The emulate message sending, but never leave the current network
• There is no way to test omnichain applications using already deployed contracts on forked chains

Solution:

The solution we came up with @shankars99 have these advantages:

1- It let you create and configure one endpoints for each fork you want to test
2- ensures oapps wires up thru the forks
3- It will let ppl test messaging and interact with already deployed contracts

Example usage:

• There is a MyOapp.t.sol that works
• Production example could be if you want a messaging system and you need to use Oracles or usa Uniswap to exchange, or any other contract that is already deployed and you want to test with those contracts.

Next steps:

1. Add something similar with hardhat (its possible to use the hardhat-switch-network plugin or similar
2. Add documentation on how to use this
3. Add the possibility to have more endpoints by fork

[ItsAdel]

As discussed earlier not all changes in this PR reflect all the changes of the fork chains as done so in the branch. This PR seems moreso to address the priceFeeds and makes additional updates to the branch utilizing vm.selectFork which lgtm 🚢

I think this should be approved to be merged into the feature branch. And then another PR to merge this entire branch to main will be made which will reflect all the changes and give the bigger picture.

Also @DanL0 to address the worry about backward compatibility for other tests,
the older tests run as before.
(Review f39c9be )

function setUpEndpoints(uint8 _endpointNum, LibraryType _libraryType)
function createEndpoints(
        uint8 _endpointNum,
        LibraryType _libraryType,
        address[] memory nativeTokenAddresses
)
function createEndpoints(
        uint8 _endpointNum,
        LibraryType _libraryType,
        address[] memory nativeTokenAddresses,
        string[] memory forkUrls
)

are setup to overload the functions as necessary. Passing a default forkUrls array if not specified by old tests. Here it ensures the old tests run as they were before. Only new tests where forkUrls are passed will run the tests with this new fork feature.

[shankars99]

lets keep this hanging another day. i need to look into the changes. i thought alderian was merging this into main and not into my branch lol

[Alderian]

Hi... I forked on my github from LZ branch created by @shankars99 because I assumed I wouldn't have permission to commit here. Then I fixed @DanL0 comments and some little stuff and added the analysis of the solution to clarify.

I thought that the correct path of merge is first merge my changes to LZ branch created by Shankar and then merge to main if it's all ok...

Hope it's all.good! Lmk if I can be of help in any way

Side note... This new piece of code we cooked with Shankar helped our project to test some complex scenarios with existing contracts on forked Blockchain...

Thanks a lot!

[DanL0]

Assigning @shankars99 because this PR base branch is @shankars99 branch

[shankars99]

Hi... I forked on my github from LZ branch created by @shankars99 because I assumed I wouldn't have permission to commit here. Then I fixed @DanL0 comments and some little stuff and added the analysis of the solution to clarify.

I thought that the correct path of merge is first merge my changes to LZ branch created by Shankar and then merge to main if it's all ok...

Hope it's all.good! Lmk if I can be of help in any way

Side note... This new piece of code we cooked with Shankar helped our project to test some complex scenarios with existing contracts on forked Blockchain...

Thanks a lot!

oh no you're all good it's just that I (mostly) forgot the changes that we made and want to take another look. and also have a look at your changes

[shankars99]

lgtm + thanks for the fix and cleanup on the eid