Token Tester

✨ Test a variety of unconventional tokens against your smart contracts ✨

"Wow, it's just a modifier? Now that's ergonomic"

-chad dev

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"What do you mean you only tested with USDC?"

-anon anime-pfp

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Get Started & Usage

Install token-tester:

forge install bespoken-tokens/token-tester

Decorate your test functions with the TokenTester modifier(s)

import "forge-std/Test.sol";

// ------ Import TokenTester ------
import {TokenTester} from "token-tester/TokenTester.sol";

// ------ Inherit the TokenTester contract ------
contract ExampleTest is Test, TokenTester {
    function setUp() public {
        // initialize your contract
    }
    
    // ------ Decorate your test with `usesERC20TokenTester`                       ------
    // ------ The test is executed 22 times, each time with a different test token ------
    function testDeposit() public usesERC20TokenTester {
        deal(address(tokenTest), address(this), 100);
        
        // use the inherited `tokenTest` (an ERC20) against the contracts
        myContract.deposit(address(tokenTest), 100);
        
        // perform typical assertions
    }
}

Enable token tester when running Foundry unit tests:

TOKEN_TEST=true forge test --ffi

Example report.html:

Why Token Tester is Useful

Developers face the challenge of unknowingly interfacing with miscompliant tokens.

Hundreds¹ of² thousands³ of⁴ dollars⁵ in audits and bug bounties have been paid out for logical errors regarding token integrations. ERC standards are a growing list, now comprised of ERC-20, ERC-721, ERC-777, and ERC-4626 with more standards pending.

Token Tester provides a suite of bespoke tokens that encompass this range of standards and more, including tokens with fee-on-transfer logic, tokens with re-entrancy vulnerabilities, and tokens with malicious implementations.

Token Pool:

Our full catalog of tokens can be found here:

• weird-erc20
• More soon, which includes actually-deployed contracts

Use Cases

Token Tester can be used in a variety of scenarios, including:

• Whitelist collateral tokens - Understand how your protocol may behave when choosing to whitelist a new token standard

• Deposit accounting - Confirm that tokens sporting fee-on-transfer are accounted for correctly

• Vault reward emissions - Safely distribute rewards to users through vault emissions and be confident your re-entrancy guards work as expected

• Swap rebasing economics - Ensure that rebasing token economics are handled correctly in your AMM

TODO:cite AMP rebasing swap event

Future Work

Token Tester was started as a hackathon project for ETHDenver 2023. If useful, our intention is to expand our token-standards (to include ERC-721, ERC-1155, ERC-777, and ERC-4626)

We also hope to procure deployed tokens to expand the Token Test Pool

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Footnotes

1. prePO / approval-to-zero ↩

2. 88mph / fee-on-transfer ↩

3. Caviar / reentrancy via ERC-777 ↩

4. Rari Fuse / reentrancy via cETH ↩

5. Sushi Trident / incorrectly handling EIP-2612 Permit ↩