chai VS ava

Let's configure tests with mocha, chai and sinon on Typescript in a few steps.

These options totally depend on your requirements. For example an empty hardhat option is a very basic project sample if you need more libraries, plugins or you use Typescript later, you have to add them manually. Like @nomiclabs/hardhat-waffle , [ethereum-waffle](https://www.npmjs.com/package/ethereum-waffle), chai , @nomiclabs/hardhat-ethers , ethers , [@openzeppelin/contracts](https://www.npmjs.com/package/@openzeppelin/contracts) Because, they'll allow us to interact with Ethereum and to test our contracts.

For those of you wondering what a "Chaijs" is like I was: https://github.com/chaijs/chai

> BDD / TDD assertion framework for node.js and the browser that can be paired with any testing framework.

ES6 test setup with Mocha and Chai.

It'd be hard for me to imagine what would it be like back then to write tests if it wasn't for Enzyme. Even with Enzyme, it was noticeably harder than it is today, and I still vividly remember installing and configuring in my project Mocha, Chai, Sinon, and JSDOM, to get pretty much the same tooling that today a single library - Jest - provides out of the box, while adding numerous features on top of that.

The library offers a BDD testing style and fully exploits javascript promises - the resulting tests are simple, clear and expressive. Chakram is built on node.js, mocha, chai and request.

For this example, I am using Mocha, plus Chai for its BDD expect syntax and the chai-as-promised plugin for asynchronous matchers.

chai

We use Jest Framework for testing. Jest is not a dogma, and, of course, in its place can be any other test runner, such as Mocha or Ava. Let's focus on tests. I'll provide a short example because I don’t want to waste your time. You can find the full version here. It's crucial to read the comments in the code below. Let's go!

> In the popular jest test runner, each test file is executed in its own child process.

Is that confirmed?

I've been following this issue:

https://github.com/jestjs/jest/issues/6957

And what Jest actually does is still kind of muddy.

In contrast to that, other test runners like AVA have a clear description what happens when:

https://github.com/avajs/ava/blob/main/docs/01-writing-tests...

I've been looking at using japa or ava for web server testing but was curious what others were using and why.

Continued work on the test suite. Implementing AVA, with snapshotting. Making a lot of effort to have the snapshot directory structure match the test262 test directory structure by generating AVA test files.

You might want to give ava a spin:

https://github.com/avajs/ava/

It has a TAP reporter, but more importantly, as opposed to the more popular solutions, like Jest, the way it achieves parallelism is explained in the docs and won't change anytime soon, thus preventing wonky, hard to debug errors which occur when this part is abstracted away.

I switched to ava for that reason and have been very happy with it. But vitest looks nice, too. Thanks for the pointer.

Runs unit tests using AVA.

Last but not least important are ava, uvu and tape; they are a really light and fast test runners.

I've had some good experiences with Ava + Sinon. I've personally disliked Jest because it seemed to do some weird trickery in the background that prevented me from using ES modules.

Ava for a simpler environment than Jest, which I usually use. I need to check how to mock ESM with it, though.