test: add underscore test

[mattsse]

Motivation

Add a test to ensure contracts with underscore work.
The issue comes from Inflector::to_snake_case which removes the trailing leading and trailing _, this does not impact the method selector though, only the rust function name, which could be a problem if a contract looks like

    abigen!(
        MyContract,
        r#"[
        _hashPuzzle() (uint256)
        _hashPuzzle_() (uint256)
    ]"#
    );

because after Inflector::to_snake_case both functions are name hash_puzzle,
to_snake_case is used in a bunch of places and could be a bit tedious to fix

Solution

PR Checklist

• Added Tests
• Added Documentation
• Updated the changelog

[gakonst]

I think we need to use an actual client here, to ensure that the contract calldata is well formed. So let's do Ganache::new().spawn() and convert _hashPuzzle to a view function which returns e.g. 1, to make sure we get the right return data too?

[mattsse]

sgtm. will add this

[gakonst]

Merging - the fail is unrelated.