Testing Ethereum smart contracts that depend on real-world time is essential to ensure your smart contract works as designed. In this tutorial, we take a closer look at building the test infrastructure to support time-sensitive tests for smart contracts using Solidity, Ganache, and Truffle.

Download the NPM package

The OpenZepplein test helpers package comes bundled with a variety of tools to test your smart contract. A link to the documentation can be found here.

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

How to use the package

1) Import the time at the top of your test file in the test folder

const { time } = require('openzeppelin-test-helpers');

2) Use the time library to jump ahead in time or block numbers

Increase: Increases the time of the blockchain by duration (in seconds), and mines a new block with that timestamp.

async function time.increase(duration)

AdvanceBlock: Forces a block to be mined, incrementing the block height.

async function time.advanceBlock()

Example:

contract("ERC20", async (accounts) => {
describe("Example of testing time", () => {
it("These two transactions are 100 seconds apart", async () => {
await myToken.transfer(personOne, 1000000);
//=============================
await time.increase(100) // Increases the time by 100 seconds
await time.advanceBlock() // Increases the block
//=============================
await myToken.transfer(personOne, 1000000);
});
});
});

This is all you need to test time in your smart contract! If you need help with getting started with truffle and testing smart contracts, below is a good blog post on how to do that.

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