lib.rs

use near_contract_standards::fungible_token::metadata::{
    FungibleTokenMetadata, FungibleTokenMetadataProvider,
};
use near_contract_standards::fungible_token::FungibleToken;
use near_sdk::borsh::{self, BorshDeserialize, BorshSerialize};
use near_sdk::json_types::{ValidAccountId, U128};
use near_sdk::{env, near_bindgen, AccountId, PanicOnDefault, PromiseOrValue};

near_sdk::setup_alloc!();

#[near_bindgen]
#[derive(BorshSerialize, BorshDeserialize, PanicOnDefault)]
pub struct Contract {
    token: FungibleToken,
}

#[near_bindgen]
impl Contract {
    #[init]
    pub fn new() -> Self {
        Self {
            token: FungibleToken::new(b"t".to_vec()),
        }
    }

    pub fn mint(&mut self, account_id: ValidAccountId, amount: U128) {
        self.token.internal_register_account(account_id.as_ref());
        self.token
            .internal_deposit(account_id.as_ref(), amount.into());
    }

    pub fn burn(&mut self, account_id: ValidAccountId, amount: U128) {
        self.token
            .internal_withdraw(account_id.as_ref(), amount.into());
    }
}

near_contract_standards::impl_fungible_token_core!(Contract, token);
near_contract_standards::impl_fungible_token_storage!(Contract, token);

#[near_bindgen]
impl FungibleTokenMetadataProvider for Contract {
    fn ft_metadata(&self) -> FungibleTokenMetadata {
        unimplemented!()
    }
}

#[cfg(test)]
mod tests {
    use near_sdk::test_utils::{accounts, VMContextBuilder};
    use near_sdk::{env, testing_env, MockedBlockchain};

    use super::*;

    #[test]
    fn test_basics() {
        let mut context = VMContextBuilder::new();
        testing_env!(context.build());
        let mut contract = Contract::new();
        testing_env!(context
            .attached_deposit(125 * env::storage_byte_cost())
            .build());
        contract.mint(accounts(0), 1_000_000.into());
        assert_eq!(contract.ft_balance_of(accounts(0)), 1_000_000.into());

        testing_env!(context
            .attached_deposit(125 * env::storage_byte_cost())
            .build());
        contract.storage_deposit(Some(accounts(1)), None);
        testing_env!(context
            .attached_deposit(1)
            .predecessor_account_id(accounts(0))
            .build());
        contract.ft_transfer(accounts(1), 1_000.into(), None);
        assert_eq!(contract.ft_balance_of(accounts(1)), 1_000.into());

        contract.burn(accounts(1), 500.into());
        assert_eq!(contract.ft_balance_of(accounts(1)), 500.into());
    }
}