That repository contains the structure and integration tests for the PSP22 USD token and wrapped USD token. USD token is simple PSP22 with the ability to pause transfers. The wrapped USD token is PSP22 with two additional methods:

#[brush::trait_definition]
pub trait WrappedPSP22 {
    /// Allow a user to deposit `amount` of underlying tokens and mint `amount` of the wrapped tokens to `account`
    #[ink(message)]
    fn deposit_for(&mut self, account: AccountId, amount: Balance) -> Result<(), PSP22Error>;

    /// Allow a user to burn `amount` of wrapped tokens and withdraw the corresponding number of underlying tokens to `account`
    #[ink(message)]
    fn withdraw_to(&mut self, account: AccountId, amount: Balance) -> Result<(), PSP22Error>;
}

The user is able to deposit USD to get a WrappedUSD. The WrappedUSD is a PSP22 so the user is able to transfer, approve and etc.

To run integration tests you need to install dependency:

yarn install
cargo +nightly-2021-07-20 install europa --git=https://github.com/patractlabs/europa.git --force --locked

Run substrate node:

europa --tmp --dev

Run tests:

yarn test

Branches:

• main - contains empty structure and tests. The developer should implement contracts by himself. Running of integration tests will help to verify that contracts are implemented right.
• solution_1 - is an example of how contracts can be implemented with a simple project structure. That structure can be used when the logic of contracts is simple and you don't need interaction between your contracts. Comparison with main
• solution_2 - is an example of how contracts can be implemented with default trait implementation. That structure can be used if you have heavy logic and you need cross-contract interactions. But you don't plan that someone outside of your project will interact with your contracts. Comparison with solution_1
• solution_3 - is an example of how contracts can be implemented with generic implementation. It is a universal structure for any kind of project. Traits are defined separately and without stuff related to implementation. That allows other people to easily interact with your contracts. Comparison with solution_2