Need help with openzeppelin-test-helpers?
Click the “chat” button below for chat support from the developer who created it, or find similar developers for support.

About the developer

OpenZeppelin
185 Stars 64 Forks MIT License 229 Commits 28 Opened issues

Description

Assertion library for Ethereum smart contract testing

Services available

!
?

Need anything else?

Contributors list

OpenZeppelin Test Helpers

Docs NPM Package Build Status

Assertion library for Ethereum smart contract testing. Make sure your contracts behave as expected.

Test Helpers integrates seamlessly with OpenZeppelin Test Environment, but it also supports Truffle tests and regular web3 workflows.

Overview

Installation

npm install --save-dev @openzeppelin/test-helpers

Hardhat (formerly Buidler)

Install

web3
and the
hardhat-web3
plugin.
npm install --save-dev @nomiclabs/hardhat-web3 web3

Remember to include the plugin in your configuration as explained in the installation instructions.

Usage

Import

@openzeppelin/test-helpers
in your test files to access the different assertions and utilities.

Note: The following snippet uses OpenZeppelin Test Environment: a Truffle-based setup would work the same way.

const { accounts, contract } = require('@openzeppelin/test-environment');

const { BN, // Big Number support constants, // Common constants, like the zero address and largest integers expectEvent, // Assertions for emitted events expectRevert, // Assertions for transactions that should fail } = require('@openzeppelin/test-helpers');

const ERC20 = contract.fromArtifact('ERC20');

describe('ERC20', function () { const [sender, receiver] = accounts;

beforeEach(async function () { // The bundled BN library is the same one web3 uses under the hood this.value = new BN(1);

this.erc20 = await ERC20.new();

});

it('reverts when transferring tokens to the zero address', async function () { // Conditions that trigger a require statement can be precisely tested await expectRevert( this.erc20.transfer(constants.ZERO_ADDRESS, this.value, { from: sender }), 'ERC20: transfer to the zero address', ); });

it('emits a Transfer event on successful transfers', async function () { const receipt = await this.erc20.transfer( receiver, this.value, { from: sender } );

// Event assertions can verify that the arguments are the expected ones
expectEvent(receipt, 'Transfer', {
  from: sender,
  to: receiver,
  value: this.value,
});

});

it('updates balances on successful transfers', async function () { this.erc20.transfer(receiver, this.value, { from: sender });

// BN assertions are automatically available via chai-bn (if using Chai)
expect(await this.erc20.balanceOf(receiver))
  .to.be.bignumber.equal(this.value);

}); });

Learn More

License

MIT

We use cookies. If you continue to browse the site, you agree to the use of cookies. For more information on our use of cookies please see our Privacy Policy.