Add tests for `FungibleTokenTransferController`

[saadjhk]

Testing the FungibleTokenTransferController

FungibleTokenTransferController houses most of the logic required to initiate fungible transfers using buildwithsygma/sygma-sdk-core. However, since there are no tests written so far I would like to write down the approach and setup required to test its functionality.

Mocking

In order to test functionality of the controller itself, we will have to mock its dependancies. Controller logic is coupled with the following components:

• host element that it binds itself to
• walletContext that provides EVM connected wallet address and provider.
• substrateProviderContext that provides substrate connected wallet addresses and providers.
• Config from @buildwithsygma/sygma-sdk-core
  • getDomainConfig should return a config for mocked domain
  • init method should prepare a fake configuration on which the transfer functionality can be simulated
  • getDomains should return list of fake domains

For testing EVM and Substrate Build and execute methods

• EVMAssetTransfer from @buildwithsygma/sygma-sdk-core
  • init method
  • createFungibleTransfer returns a mocked Transfer<Fungible> object
  • getFee returns a mocked EvmFee
  • buildApprovals returns list of mocked EVM approval transactions
  • buildTransferTransaction returns a EVM transfer transaction
• Web3Provider from ethers
  • getSigner method that returns a fake signer
• Signer from ethers
  • estimateGas returns a mocked estimated gas price of a transaction
  • getGasPrice returns a fake gas price
• TransactionResponse from ethers
  • wait method that resolves a mocked Receipt
• TransactionRequest from ethers
• SubstrateAssetTransfer from @buildwithsygma/sygma-sdk-core
  • createFungibleTransfer returns a mocked SubstrateAssetTransfer instance
  • init fake init
  • getFee returns mocked fee
  • buildTransferTransaction returns a mocked SubstrateTransaction
  • SubstrateTransaction | SubmittableExtrinsic<"promise", SubmittableResult>
    • paymentInfo method that returns mocked payment info
    • signAndSend method that simulates a transfer transaction

Approach to testing

Goal is to test the logic within FungibleTokenTransferController assuming that most of its dependancies would be using mocked values. Have a configuration of two EVM chains and one substrate chain each having a resource that can be transferred bi-directionally.

Test cases

• SDK is initialized on creation
• Correct routes are computed using mocked domains
• Resource selection should be important
• Transactions are prepared correctly
• Correct state is maintained throughout a transfer cycle
• Reset functionality works correctly
• Wallet connection is a required dependancy
• Fee is defined once transactions are prepared
• Estimated Gas is calculated on each transaction