Jest Crash Course - Unit Testing in JavaScript

In this video we will get started with JavaScript unit testing using Jest. We will look at how to setup Jest, different matchers as well as how to test async code, run functions before and after different tests, etc. This is for developers that are fairly new to testing and the Jest testing framework.
Code: Github Repo:
github.com/bradtraversy/jest_...
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[@n_fan329]

56:04 PLEASE !!! don't ever say sorry bro, contrary you are a LIFE SAVER and we should all of us thank you 👍👍👍👍

[@sumnickd]

I vibe with this comment SO hard

[@pingnikhil]

Couldn't agree more! However now, you must say "sorry" for saying "sorry". :-)

[@StrangeIndeed]

Now I've realized why is it called Jest. It's 'Test', but instead of T, there's J - for JavaScript

[@greenstarlover1]

Surely you must jest.

[@sab0004]

mind blown

[@rayc3103]

Brad,, I just got a new job (with the help of your videos, of course). One of my first assignments at my job was to create a form with Material UI. I went through a bunch of docs online, but still didn't understand the grid system. I went through your crash course in a half hour and learned what I needed to finish. Thank you for the videos.

[@joydeepr007]

I got placed in Thomson Reuters. A many many thanks to you sir, keep giving us such education always, I have learned a lot from you. Thank You.

[@BEARCLAWQ]

This made far more sense to me than the 4 hour course I just watched on Pluralsight. Thank you and please do more.

[@GooseGumlizzard]

YES. I just finished your crash course videos on Node and Express, next on my list was Jest, i search it up and was so relieved to see that you made a video on it as well. You're the best on the web, Brad!

[@tarunrv1]

Thank you so much!! This is just perfect! Got a headstart in Jest within an hour.

[@adamboostani6237]

Excellent introduction. Looking forward to the advance course!

[@deepumon.d3148]

This is the first video I have never skipped in any point.

[@joem8251]

Your tutorials may be the best! Your concise presentation, your habit of citing requirements for doing X, and how you organize concepts with top-level descriptions that accompanies details are helpful. My favorite part of your presentation style is how you say a lot with very little but elaborate where necessary with minimal redundancy. Another Example: "We could have installed JEST globally and use JEST commands, but here we install JEST locally and use a script" -- that is extremely useful for beginners learning on their own who may become frustrated if they don't know to look for the difference while exploring other resources.

[@alexstulov7219]

Thank you for saving my time learning all this from jest docs)

[@kirillvoloshin2065]

you are a legend, Brad! I have just added unit testing to my project to check the whole js file with database calls (had to wrap the file and add custom database call functions to imitate calls and response). Jest tests are great since I no longer need to manually test for cases like I used to for previous 2 years!

[@jamesbrittan]

This is a great intro to Jest, thanks. I would really like to see a video or series about how to use this in an app or more on test driven development practices generally.

[@budkin]

Your videos are clear, concise, and super useful. Thank you so much for everything you do Brad!

[@ryanchristensen643]

Thank you! I recently got hired as a developer and your videos have helped me a lot! The way you describe things makes it easier to grasp the concepts, keep up the good work :)

[@aniruddharaje8]

Love your courses Brad, I have been a big fan over the years and I suggest your awesome courses to all of my friends and colleagues, you have massively helped so many people in need of clearing concepts in simple language. Big love from India 🙏

[@mazaismaiss]

It was a fantastic journey through testing basics! Helped a lot!

[@altcoelho]

Thank you so much. I've been waiting for this Jest tutoruial!

[@mfdebian]

As always, great video Brad, to the point, concise and explanatory. Thanks!

[@alex_blue5802]

I love this. I already feel so much more confident with Jest.

[@jefjef418]

I love you traversy media

[@AhmedOsama5]

this guy is really good and helpful make sure you play 1.5 speed while watching

[@karma_yogi_42]

what a life saver! got interview in 1 hr and this will help a lot gold. absolute gold

[@theunsalted]

How did it go ?

[@wengin]

Thank you very much for this tutorial and everything you publish! It's so helpful since you can explain very well, have the right speed and explain in an order that just makes you understand everything easily. I've been working as professional in a React project, have many years of Java experience and still learning Javascript, Typescript and everything and have been learning by reading code from our projects and KZbin tutorials. I've written a lot of tests, but wanted to get a good foundation on Jest. This tutorial has just been perfect for this purpose.

[@doubleroti2010]

This is awesome. I am in the process of learning unit testing and this was a brilliant intro video tutorial. Thanks :)

[@dawidgaleziewski3335]

That was great. Your content is just gold. Thank you for sharing Brad.

[@davidrhodes7126]

Great refresher; Really helped me add some robustness to my test suites today.

[@ymazalmazal1757]

Wow, thank you so much for sharing and taking so much time to produce.

[@Codeytek]

Explained it in a very simple manner. Good work!

[@pyakz6474]

been watching this guy since last year, now i am employed.

[@aduhaneh1057]

Thank god this is free. Just watched a series of same topic that stopped halfway because the rest of the series is behind a paywall. You're a good man! Thank you!

[@shoto1673]

Thank you so much! It's kind hard to find a really good class about jest and you got to explain perfectly what I was looking for :) .

[@praveenpoonja95]

I wanted to watch this video for 10 minutes and continue watching tomorrow but this video was so mesmerising that I completed watching full video. Thank you Brad😊

[@tommyleong8328]

Appreciate on your video content. As a beginner picking up Jest, your guide is really helpful. Thank you!

[@paulthomas1052]

Great introduction to Jest Testing - really enjoyed the flow and content :)

[@paul_M007]

Thank you for this video.. You have made Jest a lot easier for me !!!! Thank you!

[@immanueldiai8089]

Thank you so much for this great tutorial!

[@kramseyart7663]

Hey Brad, thanks so much for these videos! I've been following for years, and attribute half of my success in landing a job as a software engineer to looking up most missing info/references from your content :) Despite being on the job for 9 months now, I still find myself struggling to write unit tests, and turned to this video for a refresher. Seems like a great intro/beginner tutorial, thought I have a hard time finding any material online that really gives a solid intermediate-to-advanced level of Jest education. If you think it would be worthwhile, I would personally love to see an updated, comprehensive Jest tutorial that defines variables via DOM traversal and testing nested if/else conditions, explains ShallowWrapper vs ReactWrapper, and tests updated views after changing state, etc. Again, I haven't seen anything like this done before, so might be something to look into - and I know I'd certainly appreciate having a high quality reference point in the future as well! Thanks for the time, keep up the amazing work!

[@opium4880]

This was great, thanks for the walkthrough :)

[@smonkey001]

A test environment setup with in-memory MongoDB and mongoose doing REST end point testing will be extremely helpful.

[@lardosian]

Thanks Brad, I'm gonna use this to test some React stuff.

[@WorklLife]

Thanks for the examples of testing asynchronous code !

[@mightysubbuswaroop]

Really nice introduction to jest... Thanks dude

[@cyntler-softwaredeveloper637]

Jest is the best JavaScript testing framework in my opinion. Thank you Brad for video!

[@alokranjan476]

Very nice and informative video Brad. I also watched a tutorial on PluralSight but this is far more better. Thanks a lot. I request you to bring a comprehensive video on Jest & Enzyme.

[@adarshanayak8392]

This was one of the best videos on JavaScript testing , I have watched on KZbin.

[@vikram87in]

still relevant after 4 years.. great video 😍

[@dboland17]

Thank you for making this video - really really helpful and very well explained. You are exceptionally clear.

[@vinodsamudrala]

Excellent beginning for jest l loved it. thank you so much 🙏🙏

[@sdmc79]

Brilliant tutorial, really well explained! Thanks

[@mikea.cedric9337]

Amazing Video, Brad. Thank you!

[@degisewmengist3260]

All of your videos are very interesting and stick to the point. thank you.

[@samrey8134]

I love you.... saved me dude...im in Interview mood for past 3 weeks... . ......

[@samerkayali4525]

Much thanks for your content. this tutorial is amazing!!

[@urbanpuma9136]

Thank you Brad. Your videos are super helpful 👍

[@nilana9107]

Awesome video thanks a lot Brad ...hopefully understood concepts,please let’s go and deep dive into jest+puppeteer

[@talkohavy]

13:16 "Or as 99% percent of you call me - Tra↓ver↑sy↓" Im dyingggg 🤣🤣🤣 That's totally me!

[@mikecastor2047]

Truly excellent video. Thank you!

[@jannahhossain949]

absolutely amazing tutorial!

[@abhishekchakole5070]

Thanks Brad for this tutorial

[@kamrannazir2563]

Thanks for these videos man.

[@AnumitKaur0211]

Thanks a bunch !! This was super helpful for a newbie like me

[@frayz38lyve]

Thanks so much... You're my university!!

[@H1L1CH]

Great video! Helped me a lot! Thank you for uploading it for free!

[@thewatcher305]

Absolutely amazing video!

[@riothardy101]

Thank you brad :)

[@shail95]

Fantastic Tutorial for beginner! Great Job!

[@gloriachen4415]

Thanks a lot. Learn a lot from your unit testing lesson

[@rabatstadttv]

thanks for your tutorial brother, i really aperciate what you're doing.

[@praveenreddyadelli8094]

Wow, This is a awesome. It would be great help if you could also do advanced jest concepts like snapshot testing and all.

[@kreeeeedz]

I would like to see complex test such with classes and stubbing mocking dependencies like fetch data or write data to filesystem.

[@marsdwarf]

Perfect, this tutorial has examples and is easy to follow. Thanks!

[@naveen-ib5ly]

Thanks u so much bro ...keeep up the good work

[@lukasluftlaufer1093]

I don't know how many times I've already wrote this comment under one of your videos, but: Thanks a ton, Brad! You are the best.

[@himanshushekhar3694]

Thanks a ton for a detailed video!!

[@elit5raax]

Thank you this is really helpful

[@venkateshmanigandla8725]

Great video Brad. Thank you

[@rawang45]

This is extremely helpful, tq so much!

[@ideacodinglab]

This guy is awesome. I have no idea why he has just this number of subscribers!

[@joepage3065]

Great tutorial. thanks for sharing.

[@radovansurlak7445]

Thank you Brad! :)

[@MarcoSync]

Awesome! Thanks Brad!

[@igor_cojocaru]

Hi Brad. Thank you for sharing your knowledge. Will you do some TDD series or intro to Test Driven Development tutorial? It would be great if you will do something like this with Jest and Cypress. Thanks a lot again!

[@adriandinca5682]

Great job man! Just when I was getting into unit testing! :D Can you do a crash course one mocha as well? (I know you already have a video but I think it's a bit too short)

[@aliplaysgtr]

Excellent, thank you !

[@abdelaziznassif3845]

Thank you for such great tutuorial

[@retiar2111]

LOVE YOU BRAD! :')))

[@yusefkhan1752]

Excellent video. Liked before watching, and I know I won’t be disappointed.

[@GooseGumlizzard]

haha same here

[@lucasfelipe-ze5sy]

Brad, you're the best!

[@supplyuniquenotessun4562]

many thanks for you , awesome tut :)

[@_rachid]

Thank you Mr Brad.

[@nazarpasha]

It was outstanding thanks!

[@rajgohil8610]

Thanks...helped me to learn

[@frayz38lyve]

I look forward to seeing tutorials on advanced JS features.

[@isaacquarshie2563]

Traversy Media, You are the Best

[@mohammadakbar32]

thanks brad

[@vishnuumakanthan9583]

Absolutely lovely video

[@johanncorcuff9173]

Amazing Brad !!!

[@carlosdelgado5632]

Hello thank you for all your videos are amazing would be good to see integration test videos as well

[@sriramsoumya]

great course. include mock functions also in this