wNEAR: lack of test coverage

[sept-en]

Full test coverage is an essential process in ensuring the codebase works as intended (outlined in NEAR’s design documentation). Insufficient code coverage may lead to the arisal of unexpected issues due to changes in the underlying smart contract implementation, leading to undetected changes in functionality.

Consider updating the tests for wNEAR to include interactions with storage, ft_transfer_call,
near_withdraw and other edge cases specified in the FungibleToken standard’s documentation.