allowance

function allowance(
    address owner, 
    address spender
) public view virtual override returns (uint256)

// 토큰 허용
balance = await mockToken0Contract.allowance(
        accounts[0].address, 
        routerContract.address
)

// 결과 uint256 Max의 경우
BigNumber { value: "115792089237316195423570985008687907853269984665640564039457584007913129639935" }