frangio/shared-before-each

A Mocha helper to optimize beforeEach calls in Hardhat

sharedBeforeEach and resetAfter Mocha helpers for Hardhat Network and Ganache

This repository has two Mocha helpers, sharedBeforeEach and revertAfter.

sharedBeforeEach acts like a beforeEach, but executes the initializer just once. It internally uses Hardhat Network and Ganache's snapshots and reverts instead of re-executing the initializer. Note that it doesn't revert the state after the tests are executed, so the modifications made by the last test are visible by others.

revertAfter takes a snapshot in a before hook, and reverts to it in an after.

Installation

These helpers aren't distributed in any way other than this repository, so just copy and paste them.

Usage

Just use sharedBeforeEach instead of beforeEach, and revertAfter as you want it.

Something like this:

describe("Contract C", function () {
  revertAfter();

  let c;

  sharedBeforeEach(hre.network.provider, async function () {
    c = await C.deploy();
    c.initializeSomething();
  });

  it("Test something", async function () {
    assert.equals(await c.something(), 123);
  });
});

These helpers also works with nested describe calls, just like beforeEach and after.

You can find a real example in test/example.ts.

License

This code is relased under The Unlicensed license, so you can just copy & paste it.