JavaScript Testing with Jest – Crash Course

Learn how to test JavaScript code using the Jest testing framework. Jest is a JavaScript testing framework designed to ensure correctness of any JavaScript codebase. It allows you to write tests with an approachable, familiar and feature-rich API that gives you results quickly.

✏️ Course developed by @CodeWithTomi

⭐️ Contents ⭐️
00:00 Intro
00:45 Setting Up Jest
06:22 Basic Concepts In Jest
15:31 Matchers
33:21 Testing Asynchronous Code
49:48 Mock Functions and Spies
1:00:20 Outro

🎉 Thanks to our Champion and Sponsor supporters:
👾 davthecoder
👾 jedi-or-sith
👾 南宮千影
👾 Agustín Kussrow
👾 Nattira Maneerat
👾 Heather Wcislo
👾 Serhiy Kalinets
👾 Justin Hual
👾 Otis Morgan
👾 Oscar Rahnama

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[devworks]

much needed one. please add other testing libraries as well especially ones for react

[xVantwoutMaarten]

Everything is clear, so well done, but for my taste way to easy and basic, could have gone much more in-depth for most devs. Including class mocking, actual mocking use cases, snapshots, setup /teardown, scoping, coverage, many more things I would like to see, but maybe in Part 2!

[Milan]

Wow day ago thought it was years ago. Perfect timing for me I guess

[juanmacias]

46:20
function fetchPromise(isComplete) {
return new Promise((resolve, reject) => {
if (isComplete) {
setTimeout(() => resolve('Hi'), 1000)
}
else {
setTimeout(() => reject(new Error('error')), 1000)
}
})
}

test("fetchPromise is 'Hi'", () => {
return
})


test("fetchPromise throws", () => {
return
})

[Milan]

This man offer very good explanation. Good job!

[ryanwoods]

great! how about more in-depth and with React?

[salimonwale]

Great video and lecture. I have been able to link my replit account with my github but I have been unable to link or upload the files of my repositories from replit to github. It's only showing my repositories on github but it's empty. How do I upload the files?

[dylanheslop]

I was actually looking for testing react applications... I think the last video you guys uploaded was about a year ago... would like a new updated one

[engineeringmadeasy]

At 7:28. Line 7, dont we need to replace ( "echo \"Error: no test specified\" && exit 1") with ( "jest" ). Instead of "test" with "jest"?? Can someone please clarify. Thanks

[filippotinnirello]

Got lost around 39:00, why there's a "callback" function inside fetchData? Why the test calls a function (fetchData) of a function (callback)?

[haciendadad]

Nice tutorial, but I wish there could have used a more complex example other than that sum function. Still a good video!

[JonathanKila]

Does anyone know why intellisense does not work?

[nested]

tf i was about to search jest and this video pops up loool

[ankitasood]

Can we not add two import in same file say i want to import sum and myFunction both, on executing this i am getting an error saying module not found ?

[ShoxaKardashian]

What the theme is used in your VSCode?

[juanmacias]

2:22 could have just ran "code ." from the terminal to open up VsCode :D

[AkashRaj-zcvc]

Not much help because instructor himself is not confident could have been better specially the async part.

[DukeChameleon]

I like how online courses are starting to cover indian guys giving the lecture by presenting the white guy first

[MdAJIMKhan-qccy]

সুবাহানাল্লাহিল আজিম সুবহানাল্লাহি ওয়াবি হামদিহি আস্তাগফিরুল্লাহ

[helleyequeue]

Can we move away from JS already? It’s getting toxic these days.