lopt v0.0.1

lopt

lopt is a utility package that can generate mock Solidity contracts in the form of fakes and mocks.

lopt is based in @eth-optimism/smock, sinon and sinon-chai.

Some benefits of using lopt:

• Test syntax is easy to understand, just like sinon-chai
• Supports both chai expect and should syntax
• Fully typed objects, that will extend your contract functions when using typechain (highly recommended)
• Mock and assert contract calls, without the need of even deploying it by using fakes
• If you need your contract logic, just wrap it in a mock and start asserting calls or changing behaviour
• Fully tested library

Installation

You can easily install lopt via npm:

npm install --save-dev lopt

Or via yarn:

yarn add --dev lopt

How to use

...
import { FakeContract, lopt } from 'lopt';

chai.should(); // if you like should syntax
chai.use(lopt.matchers);

describe('MyContract', () => {
    let myContractFake: FakeContract<MyContract>;

    beforeEach(async () => {
        ...
        myContractFake = await lopt.fake<MyContract>('MyContract');
    });

    it('some test', () => {
        ...
        myContractFake.bark.atCall(0).should.be.calledWith('Hello World');
    });
});

Note on using mocks

mocks requires access to the internal storage layout of your smart contracts. The Solidity compiler exposes this via the storageLayout flag, which you need to enable at your hardhat config.

Here's an example hardhat.config.ts that shows how to import the plugin:

// hardhat.config.ts
import { HardhatUserConfig } from 'hardhat/config'

const config: HardhatUserConfig = {
  ...,
  solidity: {
    version: '0.8.4',
    settings: {
      outputSelection: {
        "*": {
            "*": ["storageLayout"],
        },
      },
    }
  },
}

export default config

Why the name lopt?

Loki's alternative name is Lopt, and Loki was obviously taken.

Loki is the God of Mischief, a trickster, and the purpose of mocking libraries is basically to trick the tests.