Sepolia Testnet

Contract Diff Checker

Contract Name:
TestnetERC20

Contract Source Code:

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Address.sol)

pragma solidity ^0.8.0;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
  /**
   * @dev Returns true if `account` is a contract.
   *
   * [IMPORTANT]
   * ====
   * It is unsafe to assume that an address for which this function returns
   * false is an externally-owned account (EOA) and not a contract.
   *
   * Among others, `isContract` will return false for the following
   * types of addresses:
   *
   *  - an externally-owned account
   *  - a contract in construction
   *  - an address where a contract will be created
   *  - an address where a contract lived, but was destroyed
   * ====
   */
  function isContract(address account) internal view returns (bool) {
    // This method relies on extcodesize, which returns 0 for contracts in
    // construction, since the code is only stored at the end of the
    // constructor execution.

    uint256 size;
    assembly {
      size := extcodesize(account)
    }
    return size > 0;
  }

  /**
   * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
   * `recipient`, forwarding all available gas and reverting on errors.
   *
   * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
   * of certain opcodes, possibly making contracts go over the 2300 gas limit
   * imposed by `transfer`, making them unable to receive funds via
   * `transfer`. {sendValue} removes this limitation.
   *
   * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
   *
   * IMPORTANT: because control is transferred to `recipient`, care must be
   * taken to not create reentrancy vulnerabilities. Consider using
   * {ReentrancyGuard} or the
   * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
   */
  function sendValue(address payable recipient, uint256 amount) internal {
    require(address(this).balance >= amount, 'Address: insufficient balance');

    (bool success, ) = recipient.call{value: amount}('');
    require(success, 'Address: unable to send value, recipient may have reverted');
  }

  /**
   * @dev Performs a Solidity function call using a low level `call`. A
   * plain `call` is an unsafe replacement for a function call: use this
   * function instead.
   *
   * If `target` reverts with a revert reason, it is bubbled up by this
   * function (like regular Solidity function calls).
   *
   * Returns the raw returned data. To convert to the expected return value,
   * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
   *
   * Requirements:
   *
   * - `target` must be a contract.
   * - calling `target` with `data` must not revert.
   *
   * _Available since v3.1._
   */
  function functionCall(address target, bytes memory data) internal returns (bytes memory) {
    return functionCall(target, data, 'Address: low-level call failed');
  }

  /**
   * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
   * `errorMessage` as a fallback revert reason when `target` reverts.
   *
   * _Available since v3.1._
   */
  function functionCall(
    address target,
    bytes memory data,
    string memory errorMessage
  ) internal returns (bytes memory) {
    return functionCallWithValue(target, data, 0, errorMessage);
  }

  /**
   * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
   * but also transferring `value` wei to `target`.
   *
   * Requirements:
   *
   * - the calling contract must have an ETH balance of at least `value`.
   * - the called Solidity function must be `payable`.
   *
   * _Available since v3.1._
   */
  function functionCallWithValue(
    address target,
    bytes memory data,
    uint256 value
  ) internal returns (bytes memory) {
    return functionCallWithValue(target, data, value, 'Address: low-level call with value failed');
  }

  /**
   * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
   * with `errorMessage` as a fallback revert reason when `target` reverts.
   *
   * _Available since v3.1._
   */
  function functionCallWithValue(
    address target,
    bytes memory data,
    uint256 value,
    string memory errorMessage
  ) internal returns (bytes memory) {
    require(address(this).balance >= value, 'Address: insufficient balance for call');
    require(isContract(target), 'Address: call to non-contract');

    (bool success, bytes memory returndata) = target.call{value: value}(data);
    return verifyCallResult(success, returndata, errorMessage);
  }

  /**
   * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
   * but performing a static call.
   *
   * _Available since v3.3._
   */
  function functionStaticCall(
    address target,
    bytes memory data
  ) internal view returns (bytes memory) {
    return functionStaticCall(target, data, 'Address: low-level static call failed');
  }

  /**
   * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
   * but performing a static call.
   *
   * _Available since v3.3._
   */
  function functionStaticCall(
    address target,
    bytes memory data,
    string memory errorMessage
  ) internal view returns (bytes memory) {
    require(isContract(target), 'Address: static call to non-contract');

    (bool success, bytes memory returndata) = target.staticcall(data);
    return verifyCallResult(success, returndata, errorMessage);
  }

  /**
   * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
   * but performing a delegate call.
   *
   * _Available since v3.4._
   */
  function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
    return functionDelegateCall(target, data, 'Address: low-level delegate call failed');
  }

  /**
   * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
   * but performing a delegate call.
   *
   * _Available since v3.4._
   */
  function functionDelegateCall(
    address target,
    bytes memory data,
    string memory errorMessage
  ) internal returns (bytes memory) {
    require(isContract(target), 'Address: delegate call to non-contract');

    (bool success, bytes memory returndata) = target.delegatecall(data);
    return verifyCallResult(success, returndata, errorMessage);
  }

  /**
   * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
   * revert reason using the provided one.
   *
   * _Available since v4.3._
   */
  function verifyCallResult(
    bool success,
    bytes memory returndata,
    string memory errorMessage
  ) internal pure returns (bytes memory) {
    if (success) {
      return returndata;
    } else {
      // Look for revert reason and bubble it up if present
      if (returndata.length > 0) {
        // The easiest way to bubble the revert reason is using memory via assembly

        assembly {
          let returndata_size := mload(returndata)
          revert(add(32, returndata), returndata_size)
        }
      } else {
        revert(errorMessage);
      }
    }
  }
}

// SPDX-License-Identifier: MIT
pragma solidity 0.8.10;

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
  function _msgSender() internal view virtual returns (address payable) {
    return payable(msg.sender);
  }

  function _msgData() internal view virtual returns (bytes memory) {
    this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
    return msg.data;
  }
}

// SPDX-License-Identifier: MIT

pragma solidity 0.8.10;

import './Context.sol';
import './IERC20.sol';
import './SafeMath.sol';
import './Address.sol';

/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20PresetMinterPauser}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * We have followed general OpenZeppelin guidelines: functions revert instead
 * of returning `false` on failure. This behavior is nonetheless conventional
 * and does not conflict with the expectations of ERC20 applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20 is Context, IERC20 {
  using SafeMath for uint256;
  using Address for address;

  mapping(address => uint256) private _balances;

  mapping(address => mapping(address => uint256)) private _allowances;

  uint256 private _totalSupply;

  string private _name;
  string private _symbol;
  uint8 private _decimals;

  /**
   * @dev Sets the values for {name} and {symbol}, initializes {decimals} with
   * a default value of 18.
   *
   * To select a different value for {decimals}, use {_setupDecimals}.
   *
   * All three of these values are immutable: they can only be set once during
   * construction.
   */
  constructor(string memory name, string memory symbol) {
    _name = name;
    _symbol = symbol;
    _decimals = 18;
  }

  /**
   * @dev Returns the name of the token.
   */
  function name() public view returns (string memory) {
    return _name;
  }

  /**
   * @dev Returns the symbol of the token, usually a shorter version of the
   * name.
   */
  function symbol() public view returns (string memory) {
    return _symbol;
  }

  /**
   * @dev Returns the number of decimals used to get its user representation.
   * For example, if `decimals` equals `2`, a balance of `505` tokens should
   * be displayed to a user as `5,05` (`505 / 10 ** 2`).
   *
   * Tokens usually opt for a value of 18, imitating the relationship between
   * Ether and Wei. This is the value {ERC20} uses, unless {_setupDecimals} is
   * called.
   *
   * NOTE: This information is only used for _display_ purposes: it in
   * no way affects any of the arithmetic of the contract, including
   * {IERC20-balanceOf} and {IERC20-transfer}.
   */
  function decimals() public view returns (uint8) {
    return _decimals;
  }

  /**
   * @dev See {IERC20-totalSupply}.
   */
  function totalSupply() public view override returns (uint256) {
    return _totalSupply;
  }

  /**
   * @dev See {IERC20-balanceOf}.
   */
  function balanceOf(address account) public view override returns (uint256) {
    return _balances[account];
  }

  /**
   * @dev See {IERC20-transfer}.
   *
   * Requirements:
   *
   * - `recipient` cannot be the zero address.
   * - the caller must have a balance of at least `amount`.
   */
  function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
    _transfer(_msgSender(), recipient, amount);
    return true;
  }

  /**
   * @dev See {IERC20-allowance}.
   */
  function allowance(
    address owner,
    address spender
  ) public view virtual override returns (uint256) {
    return _allowances[owner][spender];
  }

  /**
   * @dev See {IERC20-approve}.
   *
   * Requirements:
   *
   * - `spender` cannot be the zero address.
   */
  function approve(address spender, uint256 amount) public virtual override returns (bool) {
    _approve(_msgSender(), spender, amount);
    return true;
  }

  /**
   * @dev See {IERC20-transferFrom}.
   *
   * Emits an {Approval} event indicating the updated allowance. This is not
   * required by the EIP. See the note at the beginning of {ERC20};
   *
   * Requirements:
   * - `sender` and `recipient` cannot be the zero address.
   * - `sender` must have a balance of at least `amount`.
   * - the caller must have allowance for ``sender``'s tokens of at least
   * `amount`.
   */
  function transferFrom(
    address sender,
    address recipient,
    uint256 amount
  ) public virtual override returns (bool) {
    _transfer(sender, recipient, amount);
    _approve(
      sender,
      _msgSender(),
      _allowances[sender][_msgSender()].sub(amount, 'ERC20: transfer amount exceeds allowance')
    );
    return true;
  }

  /**
   * @dev Atomically increases the allowance granted to `spender` by the caller.
   *
   * This is an alternative to {approve} that can be used as a mitigation for
   * problems described in {IERC20-approve}.
   *
   * Emits an {Approval} event indicating the updated allowance.
   *
   * Requirements:
   *
   * - `spender` cannot be the zero address.
   */
  function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
    _approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
    return true;
  }

  /**
   * @dev Atomically decreases the allowance granted to `spender` by the caller.
   *
   * This is an alternative to {approve} that can be used as a mitigation for
   * problems described in {IERC20-approve}.
   *
   * Emits an {Approval} event indicating the updated allowance.
   *
   * Requirements:
   *
   * - `spender` cannot be the zero address.
   * - `spender` must have allowance for the caller of at least
   * `subtractedValue`.
   */
  function decreaseAllowance(
    address spender,
    uint256 subtractedValue
  ) public virtual returns (bool) {
    _approve(
      _msgSender(),
      spender,
      _allowances[_msgSender()][spender].sub(
        subtractedValue,
        'ERC20: decreased allowance below zero'
      )
    );
    return true;
  }

  /**
   * @dev Moves tokens `amount` from `sender` to `recipient`.
   *
   * This is internal function is equivalent to {transfer}, and can be used to
   * e.g. implement automatic token fees, slashing mechanisms, etc.
   *
   * Emits a {Transfer} event.
   *
   * Requirements:
   *
   * - `sender` cannot be the zero address.
   * - `recipient` cannot be the zero address.
   * - `sender` must have a balance of at least `amount`.
   */
  function _transfer(address sender, address recipient, uint256 amount) internal virtual {
    require(sender != address(0), 'ERC20: transfer from the zero address');
    require(recipient != address(0), 'ERC20: transfer to the zero address');

    _beforeTokenTransfer(sender, recipient, amount);

    _balances[sender] = _balances[sender].sub(amount, 'ERC20: transfer amount exceeds balance');
    _balances[recipient] = _balances[recipient].add(amount);
    emit Transfer(sender, recipient, amount);
  }

  /** @dev Creates `amount` tokens and assigns them to `account`, increasing
   * the total supply.
   *
   * Emits a {Transfer} event with `from` set to the zero address.
   *
   * Requirements
   *
   * - `to` cannot be the zero address.
   */
  function _mint(address account, uint256 amount) internal virtual {
    require(account != address(0), 'ERC20: mint to the zero address');

    _beforeTokenTransfer(address(0), account, amount);

    _totalSupply = _totalSupply.add(amount);
    _balances[account] = _balances[account].add(amount);
    emit Transfer(address(0), account, amount);
  }

  /**
   * @dev Destroys `amount` tokens from `account`, reducing the
   * total supply.
   *
   * Emits a {Transfer} event with `to` set to the zero address.
   *
   * Requirements
   *
   * - `account` cannot be the zero address.
   * - `account` must have at least `amount` tokens.
   */
  function _burn(address account, uint256 amount) internal virtual {
    require(account != address(0), 'ERC20: burn from the zero address');

    _beforeTokenTransfer(account, address(0), amount);

    _balances[account] = _balances[account].sub(amount, 'ERC20: burn amount exceeds balance');
    _totalSupply = _totalSupply.sub(amount);
    emit Transfer(account, address(0), amount);
  }

  /**
   * @dev Sets `amount` as the allowance of `spender` over the `owner`s tokens.
   *
   * This is internal function is equivalent to `approve`, and can be used to
   * e.g. set automatic allowances for certain subsystems, etc.
   *
   * Emits an {Approval} event.
   *
   * Requirements:
   *
   * - `owner` cannot be the zero address.
   * - `spender` cannot be the zero address.
   */
  function _approve(address owner, address spender, uint256 amount) internal virtual {
    require(owner != address(0), 'ERC20: approve from the zero address');
    require(spender != address(0), 'ERC20: approve to the zero address');

    _allowances[owner][spender] = amount;
    emit Approval(owner, spender, amount);
  }

  /**
   * @dev Sets {decimals} to a value other than the default one of 18.
   *
   * WARNING: This function should only be called from the constructor. Most
   * applications that interact with token contracts will not expect
   * {decimals} to ever change, and may work incorrectly if it does.
   */
  function _setupDecimals(uint8 decimals_) internal {
    _decimals = decimals_;
  }

  /**
   * @dev Hook that is called before any transfer of tokens. This includes
   * minting and burning.
   *
   * Calling conditions:
   *
   * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
   * will be to transferred to `to`.
   * - when `from` is zero, `amount` tokens will be minted for `to`.
   * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
   * - `from` and `to` are never both zero.
   *
   * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
   */
  function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual {}
}

// SPDX-License-Identifier: AGPL-3.0
pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
  /**
   * @dev Returns the amount of tokens in existence.
   */
  function totalSupply() external view returns (uint256);

  /**
   * @dev Returns the amount of tokens owned by `account`.
   */
  function balanceOf(address account) external view returns (uint256);

  /**
   * @dev Moves `amount` tokens from the caller's account to `recipient`.
   *
   * Returns a boolean value indicating whether the operation succeeded.
   *
   * Emits a {Transfer} event.
   */
  function transfer(address recipient, uint256 amount) external returns (bool);

  /**
   * @dev Returns the remaining number of tokens that `spender` will be
   * allowed to spend on behalf of `owner` through {transferFrom}. This is
   * zero by default.
   *
   * This value changes when {approve} or {transferFrom} are called.
   */
  function allowance(address owner, address spender) external view returns (uint256);

  /**
   * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
   *
   * Returns a boolean value indicating whether the operation succeeded.
   *
   * IMPORTANT: Beware that changing an allowance with this method brings the risk
   * that someone may use both the old and the new allowance by unfortunate
   * transaction ordering. One possible solution to mitigate this race
   * condition is to first reduce the spender's allowance to 0 and set the
   * desired value afterwards:
   * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
   *
   * Emits an {Approval} event.
   */
  function approve(address spender, uint256 amount) external returns (bool);

  /**
   * @dev Moves `amount` tokens from `sender` to `recipient` using the
   * allowance mechanism. `amount` is then deducted from the caller's
   * allowance.
   *
   * Returns a boolean value indicating whether the operation succeeded.
   *
   * Emits a {Transfer} event.
   */
  function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

  /**
   * @dev Emitted when `value` tokens are moved from one account (`from`) to
   * another (`to`).
   *
   * Note that `value` may be zero.
   */
  event Transfer(address indexed from, address indexed to, uint256 value);

  /**
   * @dev Emitted when the allowance of a `spender` for an `owner` is set by
   * a call to {approve}. `value` is the new allowance.
   */
  event Approval(address indexed owner, address indexed spender, uint256 value);
}

// SPDX-License-Identifier: MIT

pragma solidity 0.8.10;

import './Context.sol';

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
contract Ownable is Context {
  address private _owner;

  event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

  /**
   * @dev Initializes the contract setting the deployer as the initial owner.
   */
  constructor() {
    address msgSender = _msgSender();
    _owner = msgSender;
    emit OwnershipTransferred(address(0), msgSender);
  }

  /**
   * @dev Returns the address of the current owner.
   */
  function owner() public view returns (address) {
    return _owner;
  }

  /**
   * @dev Throws if called by any account other than the owner.
   */
  modifier onlyOwner() {
    require(_owner == _msgSender(), 'Ownable: caller is not the owner');
    _;
  }

  /**
   * @dev Leaves the contract without owner. It will not be possible to call
   * `onlyOwner` functions anymore. Can only be called by the current owner.
   *
   * NOTE: Renouncing ownership will leave the contract without an owner,
   * thereby removing any functionality that is only available to the owner.
   */
  function renounceOwnership() public virtual onlyOwner {
    emit OwnershipTransferred(_owner, address(0));
    _owner = address(0);
  }

  /**
   * @dev Transfers ownership of the contract to a new account (`newOwner`).
   * Can only be called by the current owner.
   */
  function transferOwnership(address newOwner) public virtual onlyOwner {
    require(newOwner != address(0), 'Ownable: new owner is the zero address');
    emit OwnershipTransferred(_owner, newOwner);
    _owner = newOwner;
  }
}

// SPDX-License-Identifier: AGPL-3.0
pragma solidity 0.8.10;

/// @title Optimized overflow and underflow safe math operations
/// @notice Contains methods for doing math operations that revert on overflow or underflow for minimal gas cost
library SafeMath {
  /// @notice Returns x + y, reverts if sum overflows uint256
  /// @param x The augend
  /// @param y The addend
  /// @return z The sum of x and y
  function add(uint256 x, uint256 y) internal pure returns (uint256 z) {
    unchecked {
      require((z = x + y) >= x);
    }
  }

  /// @notice Returns x - y, reverts if underflows
  /// @param x The minuend
  /// @param y The subtrahend
  /// @return z The difference of x and y
  function sub(uint256 x, uint256 y) internal pure returns (uint256 z) {
    unchecked {
      require((z = x - y) <= x);
    }
  }

  /// @notice Returns x - y, reverts if underflows
  /// @param x The minuend
  /// @param y The subtrahend
  /// @param message The error msg
  /// @return z The difference of x and y
  function sub(uint256 x, uint256 y, string memory message) internal pure returns (uint256 z) {
    unchecked {
      require((z = x - y) <= x, message);
    }
  }

  /// @notice Returns x * y, reverts if overflows
  /// @param x The multiplicand
  /// @param y The multiplier
  /// @return z The product of x and y
  function mul(uint256 x, uint256 y) internal pure returns (uint256 z) {
    unchecked {
      require(x == 0 || (z = x * y) / x == y);
    }
  }

  /// @notice Returns x / y, reverts if overflows - no specific check, solidity reverts on division by 0
  /// @param x The numerator
  /// @param y The denominator
  /// @return z The product of x and y
  function div(uint256 x, uint256 y) internal pure returns (uint256 z) {
    return x / y;
  }
}

// SPDX-License-Identifier: AGPL-3.0
pragma solidity ^0.8.0;

import {IERC20} from '../dependencies/openzeppelin/contracts/IERC20.sol';

/**
 * @title IERC20WithPermit
 * @author Aave
 * @notice Interface for the permit function (EIP-2612)
 */
interface IERC20WithPermit is IERC20 {
  /**
   * @notice Allow passing a signed message to approve spending
   * @dev implements the permit function as for
   * https://github.com/ethereum/EIPs/blob/8a34d644aacf0f9f8f00815307fd7dd5da07655f/EIPS/eip-2612.md
   * @param owner The owner of the funds
   * @param spender The spender
   * @param value The amount
   * @param deadline The deadline timestamp, type(uint256).max for max deadline
   * @param v Signature param
   * @param s Signature param
   * @param r Signature param
   */
  function permit(
    address owner,
    address spender,
    uint256 value,
    uint256 deadline,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) external;
}

// SPDX-License-Identifier: BUSL-1.1
pragma solidity ^0.8.0;

import {Ownable} from '@aave/core-v3/contracts/dependencies/openzeppelin/contracts/Ownable.sol';
import {ERC20} from '@aave/core-v3/contracts/dependencies/openzeppelin/contracts/ERC20.sol';
import {IERC20WithPermit} from '@aave/core-v3/contracts/interfaces/IERC20WithPermit.sol';

/**
 * @title TestnetERC20
 * @dev ERC20 minting logic
 */
contract TestnetERC20 is IERC20WithPermit, ERC20, Ownable {
  bytes public constant EIP712_REVISION = bytes('1');
  bytes32 internal constant EIP712_DOMAIN =
    keccak256('EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)');
  bytes32 public constant PERMIT_TYPEHASH =
    keccak256('Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)');

  // Map of address nonces (address => nonce)
  mapping(address => uint256) internal _nonces;

  bytes32 public DOMAIN_SEPARATOR;

  constructor(
    string memory name,
    string memory symbol,
    uint8 decimals,
    address owner
  ) ERC20(name, symbol) {
    uint256 chainId = block.chainid;

    DOMAIN_SEPARATOR = keccak256(
      abi.encode(
        EIP712_DOMAIN,
        keccak256(bytes(name)),
        keccak256(EIP712_REVISION),
        chainId,
        address(this)
      )
    );
    _setupDecimals(decimals);
    require(owner != address(0));
    transferOwnership(owner);
  }

  /// @inheritdoc IERC20WithPermit
  function permit(
    address owner,
    address spender,
    uint256 value,
    uint256 deadline,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) external override {
    require(owner != address(0), 'INVALID_OWNER');
    //solium-disable-next-line
    require(block.timestamp <= deadline, 'INVALID_EXPIRATION');
    uint256 currentValidNonce = _nonces[owner];
    bytes32 digest = keccak256(
      abi.encodePacked(
        '\x19\x01',
        DOMAIN_SEPARATOR,
        keccak256(abi.encode(PERMIT_TYPEHASH, owner, spender, value, currentValidNonce, deadline))
      )
    );
    require(owner == ecrecover(digest, v, r, s), 'INVALID_SIGNATURE');
    _nonces[owner] = currentValidNonce + 1;
    _approve(owner, spender, value);
  }

  /**
   * @dev Function to mint tokens
   * @param value The amount of tokens to mint.
   * @return A boolean that indicates if the operation was successful.
   */
  function mint(uint256 value) public virtual onlyOwner returns (bool) {
    _mint(_msgSender(), value);
    return true;
  }

  /**
   * @dev Function to mint tokens to address
   * @param account The account to mint tokens.
   * @param value The amount of tokens to mint.
   * @return A boolean that indicates if the operation was successful.
   */
  function mint(address account, uint256 value) public virtual onlyOwner returns (bool) {
    _mint(account, value);
    return true;
  }

  function nonces(address owner) public view returns (uint256) {
    return _nonces[owner];
  }
}

Contract Name:
TestnetERC20

Contract Source Code:

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Address.sol)

pragma solidity ^0.8.0;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
  /**
   * @dev Returns true if `account` is a contract.
   *
   * [IMPORTANT]
   * ====
   * It is unsafe to assume that an address for which this function returns
   * false is an externally-owned account (EOA) and not a contract.
   *
   * Among others, `isContract` will return false for the following
   * types of addresses:
   *
   *  - an externally-owned account
   *  - a contract in construction
   *  - an address where a contract will be created
   *  - an address where a contract lived, but was destroyed
   * ====
   */
  function isContract(address account) internal view returns (bool) {
    // This method relies on extcodesize, which returns 0 for contracts in
    // construction, since the code is only stored at the end of the
    // constructor execution.

    uint256 size;
    assembly {
      size := extcodesize(account)
    }
    return size > 0;
  }

  /**
   * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
   * `recipient`, forwarding all available gas and reverting on errors.
   *
   * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
   * of certain opcodes, possibly making contracts go over the 2300 gas limit
   * imposed by `transfer`, making them unable to receive funds via
   * `transfer`. {sendValue} removes this limitation.
   *
   * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
   *
   * IMPORTANT: because control is transferred to `recipient`, care must be
   * taken to not create reentrancy vulnerabilities. Consider using
   * {ReentrancyGuard} or the
   * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
   */
  function sendValue(address payable recipient, uint256 amount) internal {
    require(address(this).balance >= amount, 'Address: insufficient balance');

    (bool success, ) = recipient.call{value: amount}('');
    require(success, 'Address: unable to send value, recipient may have reverted');
  }

  /**
   * @dev Performs a Solidity function call using a low level `call`. A
   * plain `call` is an unsafe replacement for a function call: use this
   * function instead.
   *
   * If `target` reverts with a revert reason, it is bubbled up by this
   * function (like regular Solidity function calls).
   *
   * Returns the raw returned data. To convert to the expected return value,
   * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
   *
   * Requirements:
   *
   * - `target` must be a contract.
   * - calling `target` with `data` must not revert.
   *
   * _Available since v3.1._
   */
  function functionCall(address target, bytes memory data) internal returns (bytes memory) {
    return functionCall(target, data, 'Address: low-level call failed');
  }

  /**
   * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
   * `errorMessage` as a fallback revert reason when `target` reverts.
   *
   * _Available since v3.1._
   */
  function functionCall(
    address target,
    bytes memory data,
    string memory errorMessage
  ) internal returns (bytes memory) {
    return functionCallWithValue(target, data, 0, errorMessage);
  }

  /**
   * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
   * but also transferring `value` wei to `target`.
   *
   * Requirements:
   *
   * - the calling contract must have an ETH balance of at least `value`.
   * - the called Solidity function must be `payable`.
   *
   * _Available since v3.1._
   */
  function functionCallWithValue(
    address target,
    bytes memory data,
    uint256 value
  ) internal returns (bytes memory) {
    return functionCallWithValue(target, data, value, 'Address: low-level call with value failed');
  }

  /**
   * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
   * with `errorMessage` as a fallback revert reason when `target` reverts.
   *
   * _Available since v3.1._
   */
  function functionCallWithValue(
    address target,
    bytes memory data,
    uint256 value,
    string memory errorMessage
  ) internal returns (bytes memory) {
    require(address(this).balance >= value, 'Address: insufficient balance for call');
    require(isContract(target), 'Address: call to non-contract');

    (bool success, bytes memory returndata) = target.call{value: value}(data);
    return verifyCallResult(success, returndata, errorMessage);
  }

  /**
   * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
   * but performing a static call.
   *
   * _Available since v3.3._
   */
  function functionStaticCall(
    address target,
    bytes memory data
  ) internal view returns (bytes memory) {
    return functionStaticCall(target, data, 'Address: low-level static call failed');
  }

  /**
   * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
   * but performing a static call.
   *
   * _Available since v3.3._
   */
  function functionStaticCall(
    address target,
    bytes memory data,
    string memory errorMessage
  ) internal view returns (bytes memory) {
    require(isContract(target), 'Address: static call to non-contract');

    (bool success, bytes memory returndata) = target.staticcall(data);
    return verifyCallResult(success, returndata, errorMessage);
  }

  /**
   * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
   * but performing a delegate call.
   *
   * _Available since v3.4._
   */
  function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
    return functionDelegateCall(target, data, 'Address: low-level delegate call failed');
  }

  /**
   * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
   * but performing a delegate call.
   *
   * _Available since v3.4._
   */
  function functionDelegateCall(
    address target,
    bytes memory data,
    string memory errorMessage
  ) internal returns (bytes memory) {
    require(isContract(target), 'Address: delegate call to non-contract');

    (bool success, bytes memory returndata) = target.delegatecall(data);
    return verifyCallResult(success, returndata, errorMessage);
  }

  /**
   * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
   * revert reason using the provided one.
   *
   * _Available since v4.3._
   */
  function verifyCallResult(
    bool success,
    bytes memory returndata,
    string memory errorMessage
  ) internal pure returns (bytes memory) {
    if (success) {
      return returndata;
    } else {
      // Look for revert reason and bubble it up if present
      if (returndata.length > 0) {
        // The easiest way to bubble the revert reason is using memory via assembly

        assembly {
          let returndata_size := mload(returndata)
          revert(add(32, returndata), returndata_size)
        }
      } else {
        revert(errorMessage);
      }
    }
  }
}

// SPDX-License-Identifier: MIT
pragma solidity 0.8.10;

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
  function _msgSender() internal view virtual returns (address payable) {
    return payable(msg.sender);
  }

  function _msgData() internal view virtual returns (bytes memory) {
    this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
    return msg.data;
  }
}

// SPDX-License-Identifier: MIT

pragma solidity 0.8.10;

import './Context.sol';
import './IERC20.sol';
import './SafeMath.sol';
import './Address.sol';

/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20PresetMinterPauser}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * We have followed general OpenZeppelin guidelines: functions revert instead
 * of returning `false` on failure. This behavior is nonetheless conventional
 * and does not conflict with the expectations of ERC20 applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20 is Context, IERC20 {
  using SafeMath for uint256;
  using Address for address;

  mapping(address => uint256) private _balances;

  mapping(address => mapping(address => uint256)) private _allowances;

  uint256 private _totalSupply;

  string private _name;
  string private _symbol;
  uint8 private _decimals;

  /**
   * @dev Sets the values for {name} and {symbol}, initializes {decimals} with
   * a default value of 18.
   *
   * To select a different value for {decimals}, use {_setupDecimals}.
   *
   * All three of these values are immutable: they can only be set once during
   * construction.
   */
  constructor(string memory name, string memory symbol) {
    _name = name;
    _symbol = symbol;
    _decimals = 18;
  }

  /**
   * @dev Returns the name of the token.
   */
  function name() public view returns (string memory) {
    return _name;
  }

  /**
   * @dev Returns the symbol of the token, usually a shorter version of the
   * name.
   */
  function symbol() public view returns (string memory) {
    return _symbol;
  }

  /**
   * @dev Returns the number of decimals used to get its user representation.
   * For example, if `decimals` equals `2`, a balance of `505` tokens should
   * be displayed to a user as `5,05` (`505 / 10 ** 2`).
   *
   * Tokens usually opt for a value of 18, imitating the relationship between
   * Ether and Wei. This is the value {ERC20} uses, unless {_setupDecimals} is
   * called.
   *
   * NOTE: This information is only used for _display_ purposes: it in
   * no way affects any of the arithmetic of the contract, including
   * {IERC20-balanceOf} and {IERC20-transfer}.
   */
  function decimals() public view returns (uint8) {
    return _decimals;
  }

  /**
   * @dev See {IERC20-totalSupply}.
   */
  function totalSupply() public view override returns (uint256) {
    return _totalSupply;
  }

  /**
   * @dev See {IERC20-balanceOf}.
   */
  function balanceOf(address account) public view override returns (uint256) {
    return _balances[account];
  }

  /**
   * @dev See {IERC20-transfer}.
   *
   * Requirements:
   *
   * - `recipient` cannot be the zero address.
   * - the caller must have a balance of at least `amount`.
   */
  function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
    _transfer(_msgSender(), recipient, amount);
    return true;
  }

  /**
   * @dev See {IERC20-allowance}.
   */
  function allowance(
    address owner,
    address spender
  ) public view virtual override returns (uint256) {
    return _allowances[owner][spender];
  }

  /**
   * @dev See {IERC20-approve}.
   *
   * Requirements:
   *
   * - `spender` cannot be the zero address.
   */
  function approve(address spender, uint256 amount) public virtual override returns (bool) {
    _approve(_msgSender(), spender, amount);
    return true;
  }

  /**
   * @dev See {IERC20-transferFrom}.
   *
   * Emits an {Approval} event indicating the updated allowance. This is not
   * required by the EIP. See the note at the beginning of {ERC20};
   *
   * Requirements:
   * - `sender` and `recipient` cannot be the zero address.
   * - `sender` must have a balance of at least `amount`.
   * - the caller must have allowance for ``sender``'s tokens of at least
   * `amount`.
   */
  function transferFrom(
    address sender,
    address recipient,
    uint256 amount
  ) public virtual override returns (bool) {
    _transfer(sender, recipient, amount);
    _approve(
      sender,
      _msgSender(),
      _allowances[sender][_msgSender()].sub(amount, 'ERC20: transfer amount exceeds allowance')
    );
    return true;
  }

  /**
   * @dev Atomically increases the allowance granted to `spender` by the caller.
   *
   * This is an alternative to {approve} that can be used as a mitigation for
   * problems described in {IERC20-approve}.
   *
   * Emits an {Approval} event indicating the updated allowance.
   *
   * Requirements:
   *
   * - `spender` cannot be the zero address.
   */
  function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
    _approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
    return true;
  }

  /**
   * @dev Atomically decreases the allowance granted to `spender` by the caller.
   *
   * This is an alternative to {approve} that can be used as a mitigation for
   * problems described in {IERC20-approve}.
   *
   * Emits an {Approval} event indicating the updated allowance.
   *
   * Requirements:
   *
   * - `spender` cannot be the zero address.
   * - `spender` must have allowance for the caller of at least
   * `subtractedValue`.
   */
  function decreaseAllowance(
    address spender,
    uint256 subtractedValue
  ) public virtual returns (bool) {
    _approve(
      _msgSender(),
      spender,
      _allowances[_msgSender()][spender].sub(
        subtractedValue,
        'ERC20: decreased allowance below zero'
      )
    );
    return true;
  }

  /**
   * @dev Moves tokens `amount` from `sender` to `recipient`.
   *
   * This is internal function is equivalent to {transfer}, and can be used to
   * e.g. implement automatic token fees, slashing mechanisms, etc.
   *
   * Emits a {Transfer} event.
   *
   * Requirements:
   *
   * - `sender` cannot be the zero address.
   * - `recipient` cannot be the zero address.
   * - `sender` must have a balance of at least `amount`.
   */
  function _transfer(address sender, address recipient, uint256 amount) internal virtual {
    require(sender != address(0), 'ERC20: transfer from the zero address');
    require(recipient != address(0), 'ERC20: transfer to the zero address');

    _beforeTokenTransfer(sender, recipient, amount);

    _balances[sender] = _balances[sender].sub(amount, 'ERC20: transfer amount exceeds balance');
    _balances[recipient] = _balances[recipient].add(amount);
    emit Transfer(sender, recipient, amount);
  }

  /** @dev Creates `amount` tokens and assigns them to `account`, increasing
   * the total supply.
   *
   * Emits a {Transfer} event with `from` set to the zero address.
   *
   * Requirements
   *
   * - `to` cannot be the zero address.
   */
  function _mint(address account, uint256 amount) internal virtual {
    require(account != address(0), 'ERC20: mint to the zero address');

    _beforeTokenTransfer(address(0), account, amount);

    _totalSupply = _totalSupply.add(amount);
    _balances[account] = _balances[account].add(amount);
    emit Transfer(address(0), account, amount);
  }

  /**
   * @dev Destroys `amount` tokens from `account`, reducing the
   * total supply.
   *
   * Emits a {Transfer} event with `to` set to the zero address.
   *
   * Requirements
   *
   * - `account` cannot be the zero address.
   * - `account` must have at least `amount` tokens.
   */
  function _burn(address account, uint256 amount) internal virtual {
    require(account != address(0), 'ERC20: burn from the zero address');

    _beforeTokenTransfer(account, address(0), amount);

    _balances[account] = _balances[account].sub(amount, 'ERC20: burn amount exceeds balance');
    _totalSupply = _totalSupply.sub(amount);
    emit Transfer(account, address(0), amount);
  }

  /**
   * @dev Sets `amount` as the allowance of `spender` over the `owner`s tokens.
   *
   * This is internal function is equivalent to `approve`, and can be used to
   * e.g. set automatic allowances for certain subsystems, etc.
   *
   * Emits an {Approval} event.
   *
   * Requirements:
   *
   * - `owner` cannot be the zero address.
   * - `spender` cannot be the zero address.
   */
  function _approve(address owner, address spender, uint256 amount) internal virtual {
    require(owner != address(0), 'ERC20: approve from the zero address');
    require(spender != address(0), 'ERC20: approve to the zero address');

    _allowances[owner][spender] = amount;
    emit Approval(owner, spender, amount);
  }

  /**
   * @dev Sets {decimals} to a value other than the default one of 18.
   *
   * WARNING: This function should only be called from the constructor. Most
   * applications that interact with token contracts will not expect
   * {decimals} to ever change, and may work incorrectly if it does.
   */
  function _setupDecimals(uint8 decimals_) internal {
    _decimals = decimals_;
  }

  /**
   * @dev Hook that is called before any transfer of tokens. This includes
   * minting and burning.
   *
   * Calling conditions:
   *
   * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
   * will be to transferred to `to`.
   * - when `from` is zero, `amount` tokens will be minted for `to`.
   * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
   * - `from` and `to` are never both zero.
   *
   * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
   */
  function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual {}
}

// SPDX-License-Identifier: AGPL-3.0
pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
  /**
   * @dev Returns the amount of tokens in existence.
   */
  function totalSupply() external view returns (uint256);

  /**
   * @dev Returns the amount of tokens owned by `account`.
   */
  function balanceOf(address account) external view returns (uint256);

  /**
   * @dev Moves `amount` tokens from the caller's account to `recipient`.
   *
   * Returns a boolean value indicating whether the operation succeeded.
   *
   * Emits a {Transfer} event.
   */
  function transfer(address recipient, uint256 amount) external returns (bool);

  /**
   * @dev Returns the remaining number of tokens that `spender` will be
   * allowed to spend on behalf of `owner` through {transferFrom}. This is
   * zero by default.
   *
   * This value changes when {approve} or {transferFrom} are called.
   */
  function allowance(address owner, address spender) external view returns (uint256);

  /**
   * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
   *
   * Returns a boolean value indicating whether the operation succeeded.
   *
   * IMPORTANT: Beware that changing an allowance with this method brings the risk
   * that someone may use both the old and the new allowance by unfortunate
   * transaction ordering. One possible solution to mitigate this race
   * condition is to first reduce the spender's allowance to 0 and set the
   * desired value afterwards:
   * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
   *
   * Emits an {Approval} event.
   */
  function approve(address spender, uint256 amount) external returns (bool);

  /**
   * @dev Moves `amount` tokens from `sender` to `recipient` using the
   * allowance mechanism. `amount` is then deducted from the caller's
   * allowance.
   *
   * Returns a boolean value indicating whether the operation succeeded.
   *
   * Emits a {Transfer} event.
   */
  function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

  /**
   * @dev Emitted when `value` tokens are moved from one account (`from`) to
   * another (`to`).
   *
   * Note that `value` may be zero.
   */
  event Transfer(address indexed from, address indexed to, uint256 value);

  /**
   * @dev Emitted when the allowance of a `spender` for an `owner` is set by
   * a call to {approve}. `value` is the new allowance.
   */
  event Approval(address indexed owner, address indexed spender, uint256 value);
}

// SPDX-License-Identifier: MIT

pragma solidity 0.8.10;

import './Context.sol';

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
contract Ownable is Context {
  address private _owner;

  event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

  /**
   * @dev Initializes the contract setting the deployer as the initial owner.
   */
  constructor() {
    address msgSender = _msgSender();
    _owner = msgSender;
    emit OwnershipTransferred(address(0), msgSender);
  }

  /**
   * @dev Returns the address of the current owner.
   */
  function owner() public view returns (address) {
    return _owner;
  }

  /**
   * @dev Throws if called by any account other than the owner.
   */
  modifier onlyOwner() {
    require(_owner == _msgSender(), 'Ownable: caller is not the owner');
    _;
  }

  /**
   * @dev Leaves the contract without owner. It will not be possible to call
   * `onlyOwner` functions anymore. Can only be called by the current owner.
   *
   * NOTE: Renouncing ownership will leave the contract without an owner,
   * thereby removing any functionality that is only available to the owner.
   */
  function renounceOwnership() public virtual onlyOwner {
    emit OwnershipTransferred(_owner, address(0));
    _owner = address(0);
  }

  /**
   * @dev Transfers ownership of the contract to a new account (`newOwner`).
   * Can only be called by the current owner.
   */
  function transferOwnership(address newOwner) public virtual onlyOwner {
    require(newOwner != address(0), 'Ownable: new owner is the zero address');
    emit OwnershipTransferred(_owner, newOwner);
    _owner = newOwner;
  }
}

// SPDX-License-Identifier: AGPL-3.0
pragma solidity 0.8.10;

/// @title Optimized overflow and underflow safe math operations
/// @notice Contains methods for doing math operations that revert on overflow or underflow for minimal gas cost
library SafeMath {
  /// @notice Returns x + y, reverts if sum overflows uint256
  /// @param x The augend
  /// @param y The addend
  /// @return z The sum of x and y
  function add(uint256 x, uint256 y) internal pure returns (uint256 z) {
    unchecked {
      require((z = x + y) >= x);
    }
  }

  /// @notice Returns x - y, reverts if underflows
  /// @param x The minuend
  /// @param y The subtrahend
  /// @return z The difference of x and y
  function sub(uint256 x, uint256 y) internal pure returns (uint256 z) {
    unchecked {
      require((z = x - y) <= x);
    }
  }

  /// @notice Returns x - y, reverts if underflows
  /// @param x The minuend
  /// @param y The subtrahend
  /// @param message The error msg
  /// @return z The difference of x and y
  function sub(uint256 x, uint256 y, string memory message) internal pure returns (uint256 z) {
    unchecked {
      require((z = x - y) <= x, message);
    }
  }

  /// @notice Returns x * y, reverts if overflows
  /// @param x The multiplicand
  /// @param y The multiplier
  /// @return z The product of x and y
  function mul(uint256 x, uint256 y) internal pure returns (uint256 z) {
    unchecked {
      require(x == 0 || (z = x * y) / x == y);
    }
  }

  /// @notice Returns x / y, reverts if overflows - no specific check, solidity reverts on division by 0
  /// @param x The numerator
  /// @param y The denominator
  /// @return z The product of x and y
  function div(uint256 x, uint256 y) internal pure returns (uint256 z) {
    return x / y;
  }
}

// SPDX-License-Identifier: AGPL-3.0
pragma solidity ^0.8.0;

import {IERC20} from '../dependencies/openzeppelin/contracts/IERC20.sol';

/**
 * @title IERC20WithPermit
 * @author Aave
 * @notice Interface for the permit function (EIP-2612)
 */
interface IERC20WithPermit is IERC20 {
  /**
   * @notice Allow passing a signed message to approve spending
   * @dev implements the permit function as for
   * https://github.com/ethereum/EIPs/blob/8a34d644aacf0f9f8f00815307fd7dd5da07655f/EIPS/eip-2612.md
   * @param owner The owner of the funds
   * @param spender The spender
   * @param value The amount
   * @param deadline The deadline timestamp, type(uint256).max for max deadline
   * @param v Signature param
   * @param s Signature param
   * @param r Signature param
   */
  function permit(
    address owner,
    address spender,
    uint256 value,
    uint256 deadline,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) external;
}

// SPDX-License-Identifier: BUSL-1.1
pragma solidity ^0.8.0;

import {Ownable} from '@aave/core-v3/contracts/dependencies/openzeppelin/contracts/Ownable.sol';
import {ERC20} from '@aave/core-v3/contracts/dependencies/openzeppelin/contracts/ERC20.sol';
import {IERC20WithPermit} from '@aave/core-v3/contracts/interfaces/IERC20WithPermit.sol';

/**
 * @title TestnetERC20
 * @dev ERC20 minting logic
 */
contract TestnetERC20 is IERC20WithPermit, ERC20, Ownable {
  bytes public constant EIP712_REVISION = bytes('1');
  bytes32 internal constant EIP712_DOMAIN =
    keccak256('EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)');
  bytes32 public constant PERMIT_TYPEHASH =
    keccak256('Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)');

  // Map of address nonces (address => nonce)
  mapping(address => uint256) internal _nonces;

  bytes32 public DOMAIN_SEPARATOR;

  constructor(
    string memory name,
    string memory symbol,
    uint8 decimals,
    address owner
  ) ERC20(name, symbol) {
    uint256 chainId = block.chainid;

    DOMAIN_SEPARATOR = keccak256(
      abi.encode(
        EIP712_DOMAIN,
        keccak256(bytes(name)),
        keccak256(EIP712_REVISION),
        chainId,
        address(this)
      )
    );
    _setupDecimals(decimals);
    require(owner != address(0));
    transferOwnership(owner);
  }

  /// @inheritdoc IERC20WithPermit
  function permit(
    address owner,
    address spender,
    uint256 value,
    uint256 deadline,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) external override {
    require(owner != address(0), 'INVALID_OWNER');
    //solium-disable-next-line
    require(block.timestamp <= deadline, 'INVALID_EXPIRATION');
    uint256 currentValidNonce = _nonces[owner];
    bytes32 digest = keccak256(
      abi.encodePacked(
        '\x19\x01',
        DOMAIN_SEPARATOR,
        keccak256(abi.encode(PERMIT_TYPEHASH, owner, spender, value, currentValidNonce, deadline))
      )
    );
    require(owner == ecrecover(digest, v, r, s), 'INVALID_SIGNATURE');
    _nonces[owner] = currentValidNonce + 1;
    _approve(owner, spender, value);
  }

  /**
   * @dev Function to mint tokens
   * @param value The amount of tokens to mint.
   * @return A boolean that indicates if the operation was successful.
   */
  function mint(uint256 value) public virtual onlyOwner returns (bool) {
    _mint(_msgSender(), value);
    return true;
  }

  /**
   * @dev Function to mint tokens to address
   * @param account The account to mint tokens.
   * @param value The amount of tokens to mint.
   * @return A boolean that indicates if the operation was successful.
   */
  function mint(address account, uint256 value) public virtual onlyOwner returns (bool) {
    _mint(account, value);
    return true;
  }

  function nonces(address owner) public view returns (uint256) {
    return _nonces[owner];
  }
}

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