Basic testing¶

Creating a provider¶

Creating a mock provider for your tests is super simple.

import { MockProvider } from 'ethereum-waffle';
const provider = new MockProvider();

This class takes an optional MockProviderOptions parameter in the constructor. Then the ganacheOptions from MockProviderOptions are passed to the underlying ganache-core implementation. You can read more about the options here.

Getting wallets¶

To obtain wallets that have been prefunded with eth use the provider

import { MockProvider } from 'ethereum-waffle';

const provider = new MockProvider();
const [wallet, otherWallet] = provider.getWallets();

// or use a shorthand

const [wallet, otherWallet] = new MockProvider().getWallets();

By default this method returns 10 wallets. You can modify the returned wallets, by changing MockProvider configuration.

import { MockProvider } from 'ethereum-waffle';
const provider = new MockProvider({
    ganacheOptions: {
      accounts: [{balance: 'BALANCE IN WEI', secretKey: 'PRIVATE KEY'}]
    }
});
const wallets = provider.getWallets();

import { MockProvider } from 'ethereum-waffle';
const provider = new MockProvider({
  accounts: [{balance: 'BALANCE IN WEI', secretKey: 'PRIVATE KEY'}]
});
const wallets = provider.getWallets();

You can also get an empty random wallet by calling:

import { MockProvider } from 'ethereum-waffle';
const provider = new MockProvider();
const wallet = provider.createEmptyWallet();

Deploying contracts¶

Once you compile your contracts using waffle, you can deploy them in your javascript code. It accepts three arguments:

wallet to send the deploy transaction
contract information (abi and bytecode)
contract constructor arguments

Deploy a contract:

import BasicTokenMock from "build/BasicTokenMock.json";

token = await deployContract(wallet, BasicTokenMock, [wallet.address, 1000]);

The contract information can be one of the following formats:

interface StandardContractJSON {
  abi: any;
  evm: {bytecode: {object: any}};
}

interface SimpleContractJSON {
  abi: any[];
  bytecode: string;
}

Linking¶

Link a library:

myLibrary = await deployContract(wallet, MyLibrary, []);
link(LibraryConsumer, 'contracts/MyLibrary.sol:MyLibrary', myLibrary.address);
libraryConsumer = await deployContract(wallet, LibraryConsumer, []);

Note

You need to use a fully qualified name as the second parameter of the link function (path to the file relative to the root of the project, followed by a colon and the contract name).