Java Unit Testing with JUnit - Tutorial - How to Create And Use Unit Tests

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Java Unit Testing with JUnit - Tutorial - How to Create And Use Unit Tests

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Күн бұрын

Full tutorial on creating Unit Tests in Java with JUnit!
Do you write Java code that you're just not confident is 100% right? You can create unit tests using the JUnit testing framework to verify your Java code, and I'll show you exactly how to do it.
Many beginners don't know there's a great way to test their code with simple, fast tests and make sure their code is working exactly how they think it is.
The IntelliJ testing tools also make creating and running your Unit Tests super simple.
In this beginner's Java tutorial video, we'll do a full walkthrough of why and how you can create your own unit tests!
Learn or improve your Java by watching it being coded live!
Hi, I'm John! I'm a Lead Java Software Engineer and I've been in the programming industry for more than a decade. I love sharing what I've learned over the years in a way that's understandable for all levels of Java learners.
Let me know what else you'd like to see!
Links to any stuff in this description are affiliate links, so if you buy a product through those links I may earn a small commission.
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Пікірлер: 446

@Roberto-oz6et 2 жыл бұрын

Your channel is pure GOLD! I'm learning more in a few minutes than an whole semester of classes.

@jeromepincus8529 10 ай бұрын

So true

@tejumania 2 жыл бұрын

Honestly there's no better refresher course on java unit testing than this. Short, precise, keeps your gears turning and leaves you wanting to know more. Thank you so much John.

@marmont8005 11 ай бұрын

Today, I crashed production because I didn't review and test my code. This was a valuable lesson for me. A colleague with more experience showed me how I could have detected this error through unit testing. We wrote 8 test cases within 20 minutes that could have assessed the functionality of my changes, and I would have noticed the bug. I am glad that we have an open culture for acknowledging errors, and that I was 'allowed' to make this mistake.

@marmont8005 11 ай бұрын

I didn't realize how I had caused this error until we received emails from the company. In a mapper method, I used .filter(Objects::isNull) in a stream filter instead of .filter(Objects::nonNull). This led to the occurrence of the error on 6000 devices. It dawned on me that a slight oversight can impact hundreds to thousands of people. From now on, I will be more conscientious and refrain from putting my code into production until I am 100% sure that it performs its intended function.

@JoeyCodes 6 ай бұрын

How are ya'll getting jobs out here not knowing how to test your code ;-;

@micleh 2 жыл бұрын

I enjoyed the topic of the video, since unit tests are not necessarily what you have to do at school (and it's not in the curriculum). What I also liked was you switching to IntelliJ. I've been experimenting with my students, and we tested 3 different IDEs. They said that they felt most comfortable with IntelliJ and also appreciated the helpful tips that guided them towards fixing errors. I'd also like to give you props for the way you present the topics, among them being voice, intonation, gestures and pace.

@noobster9212 Жыл бұрын

Truth to be told, curriculum for computer science in most university is outdated. Most lecturers stopped learning new things whereas the cs world is evolving every second.

@ngndnd Жыл бұрын

im taking a junit class rn and its a complete joke of a class.

@albertbokor6643 Жыл бұрын

We actually have a course that goes all in on these features. It feels a bit awkward to do this much stuff for a conceptually small assignemt project but still something practically useful.

@gabrielv.4358 10 ай бұрын

so true. intellij is the better of them all, and its free

@muhammadhassaanbasil8599 7 ай бұрын

Concise, Crisp & To-the-point. Short videos, really time saving. Great work John.

@Hurosaki_ 3 ай бұрын

John, i almost said that this was the most easy topic i learned in java, but when i read other comments, i realized its because your teaching method is simply great. I’m glad i found you!

@macmcleod1188 Жыл бұрын

These are all wonderful. I'm a retired Java 6 programmer writing Minecraft mods in Java 8, 16, and 17. Your videos are clear and concise! They help me a lot.

@raghavanaliassaravananm1546 2 жыл бұрын

Thanks and kudos for the Coverage aspect in Intellij IDEA.

@Chronozia 2 жыл бұрын

Hey John! I took a course in the fundamentals of computer science last year where our professor mentioned the importance of unit testing and made us all write our own ones without really explaining the reason why or showing how to properly do it. This video really cleared that up for me. Thank you so much!

@user-zj6iz1rl8d 2 ай бұрын

i wish this dude made spring boot videoes would be gold

@mastershonobi110 2 жыл бұрын

Very noice!!! As a “beginner” learning on my own these lectures are important lessons. Great Intro exposure to thinking about writing code holistically. Ty. 🙌🏿🙏🏾

@mohamedibrahim-qm1cr 2 жыл бұрын

we should be friends lol i'm also just started Java! maybe CodingMates?

@mastershonobi110 2 жыл бұрын

@@mohamedibrahim-qm1cr where are you in your journey? Are you taking a course? With who? Asking for potential friend. Lol

@mohamedibrahim-qm1cr 2 жыл бұрын

@@mastershonobi110 just in java for a week now, I'm in a bootcamp plus resource from Plural Sight.

@theblindprogrammer 2 жыл бұрын

Yes, John's instructions are clear and to the point.

@theblindprogrammer 2 жыл бұрын

@@mohamedibrahim-qm1cr Which level are you in? Did you reach objects and inheritance?

@olillin 2 жыл бұрын

I've been trying to learn unit testing for ages and this made everything so much clearer!

@pokitlui 7 күн бұрын

This video makes the JUnit test case more easily to implement. Thanks. 🎉

@paulus_germanus 2 ай бұрын

Hands down the best Java channel on YT. I love you John. You just very clearly explained to my dumb brain what the rest of the web really struggled to achieve. Thank you!

@JLSXMK8 2 жыл бұрын

A video on lambdas expressions would be so awesome, especially when the concept is partnered with runnable class instances. These together are the only way I know in java to make a responsive GUI application.

@kanchankumari2900 Ай бұрын

Run our test with coverage, John all the expected points you explained in a very simple way , Thanks for your hard work nd keep on doing such a great real time videos

@samueldnc 2 жыл бұрын

You're brilliant! I'm a senior Java developer but I don't have these didactics and ease to explain/teach. Awesome job

@gplus46 2 жыл бұрын

"run our test with coverage" was a requirement for project...Its clearer now. That was a treat. Great video

@newgentechinfo Ай бұрын

This video really helpful for my next task.Thank you so much John.

@lucasalledi Жыл бұрын

going through your classes while taking part in a bootcamp. really appreciate your help!

@CodingWithJohn Жыл бұрын

Glad it's helping!

@ultimateguru2 4 ай бұрын

Every time i look up something on youtube regarding java, and I see johns video available on that topic, what a sigh of relief, hushhhh.! 😅

@CodingWithJohn 4 ай бұрын

Let me know if there's something crucial I haven't covered yet!

@beetc305shivsundarbankar9 Жыл бұрын

Hit the like, if you have been watching many tutorials and finally, you get the proper context with clear explanations.

@greatjobbuddy 2 жыл бұрын

I need to give John some major KUDOS. I actually followed the link to his course and now, after like 10% in, I've learned at least 4 or 5 new things that are going to make my life so much easier. Thanks buddy for making these videos and adding a course. Ternary alone is going to save me so much time. A+++

@CodingWithJohn 2 жыл бұрын

Awesome, thanks! I just added the ternary lesson earlier this week, glad it's helping! I'll be continuing to add new lessons as I'm able, and anyone who has the course already will of course have access to new lessons that are added as well, forever. Also with your permission, if you're ok with it, I might also use your very kind words as a testimonial!

@greatjobbuddy 2 жыл бұрын

@@CodingWithJohn Absolutely. 100%

@greatjobbuddy 2 жыл бұрын

Sent you an email.

@nipunlakshank Жыл бұрын

This is the best beginner friendly unit testing tutorial I've found so far

@animeshsrivastavash 2 жыл бұрын

Another great video John! Looking forward to the jvm memory management video; if possible please give it a shot ...

@gabrielv.4358 10 ай бұрын

That is insanely complicated, wow! So cool!

@yogeshdharya3857 Жыл бұрын

Had an assignmen to perform unit testing in Java usign the Junit . Was recommended to watch this video of yours . Your doing a great job ceating content for beginners like me Sir John . Had to subscribe ! Keep up the good and humble work !😇

@CodingWithJohn Жыл бұрын

Awesome, I'm glad it helped! And thankful to whomever recommended it!

@adrianprayoga335 2 жыл бұрын

underrated java youtuber, man deserve more views, thanks for the tutorial

@gabrieldenobrega Жыл бұрын

Thank you for this video. It's clear that this video is just a summary of what unit tests are just like you said. However, only your video was able to really make me understand what unit testing in Java is about.

@amjadsaad9545 10 ай бұрын

I'm really thankful to you. I'm currently in the process of studying. And I researched it because my doctor didn't talk about it and I found a similarity between it and the Java language, but it's not a regular Java, it's a test for Java. Thank you. I really understand. And of course I'm proud of myself because I researched who you might laugh at. But that's true. Thank you again❤

@Tolgasah Жыл бұрын

Hi John, thanks for the video. I have to write my own unit tests for a project assignment, but have never done or got properly shown how to. This video cleared all my questions.

@oleksiil.9892 2 жыл бұрын

Very cool stuff for a java beginner like myself )) thank you!

@DC-sp4sk 2 жыл бұрын

Best video ever on JUnit by a long shot. Would really love to see more advanced videos on this topic!

@waffle8364 9 ай бұрын

The one testing framework I've ever loved and enjoyed was RSpec for Ruby or Rails. Extremely easy to setup, read and write tests.

@Wow-uj3uj 6 ай бұрын

This video has made me subscribe. So well spoken and well communicated I had no choice! Thank you for this very informative video

@my_video_collection 11 ай бұрын

now 2:23 am, but I'm sitting and watching you. It's so cool. Firstly I'm learning Java, secondly I'm improving my English (at least listening)😍

@xq510 2 жыл бұрын

THIS IS AMAZING! I loved how you provided context and explained everything so clearly!!

@DavidKirubi 2 жыл бұрын

No ADs is the silver lining to this channel. 👌

@ndk8111 2 жыл бұрын

Thanks John. Finished your lecture then went to try to implement a few of the junit5 test methods for the very first time. Your explanation was very good. One thing I wished you touched was how to resolve dependencies needed to run junit5. I grabbed one of the dependencies in mvn repository Jupiter-engine and that seemed sufficed to resolve my missing assertTrue(). These small things very briefly but ought to be covered In your demos I think.

@milenatenorio2506 10 ай бұрын

Thank you very much for the video! The teaching and English are perfect for people who do not speak English as a native language.

@eduonnetcomputer8878 Жыл бұрын

I have been watching since a year. Your videos are very simple to understand. Thank you.

@mrnoname2462 6 ай бұрын

Been exposed to introduction of JUnit today, lucky to have this lesson!

@darsanas6741 Жыл бұрын

Thanks a lot John. I started loving Java after watching your videos! This topic was so interesting.

@semilife 6 ай бұрын

John your videos are great, clear concise and informative.

@juancarloscardona5613 2 жыл бұрын

Thanks for this video! I recently joined my first hackathon and I was looking forward to using unit testing in Java for the first time, you explained it very well and it was easy to understand. Nice work :)

@carloschacon5951 2 жыл бұрын

MinTIC???

@whitneythung2792 Жыл бұрын

This is an awesome tutorial on how to write JUnit Tests. You explained this so well for a slow learner like me. Thanks for the help!

@CodingWithJohn Жыл бұрын

Glad it was helpful!

@slai2389 10 ай бұрын

Thanks for your video sincerely. Every time I learn new things from you.

@samuvisser 2 жыл бұрын

Long time programmer but never wrote a single unit test. Its this thing i know i should do, but I seriously never have time for. This video is a actually a great example, ur unit tests tend to use as much or even more lines of code than the original. In the real word the next deadline is always yesterday…

@DavidVCastro 6 ай бұрын

Amazing how much you covered in 21 minutes!

@Decent138 Жыл бұрын

i have not understands this topic in my class but now i am perfect with this topic.... Thank you professor

@samueloverspelham2322 2 жыл бұрын

As a Java developer, this channel has been very helpful to me in every way.. Thanks to you.

@diegoruiz5265 2 жыл бұрын

You are great John ! I really enjoy your videos, they are so practical but with a lot of useful information and knowledge. You do that complex topic looks really easy and funny. Keep with this awesome work. Thank you !

@ShaneSheriff 4 ай бұрын

Nice work! Really informative video and easy to follow along on

@lathavoggu2639 2 жыл бұрын

Hey John, kindly make one session for Intellij ide usage for java and maven plugin nd other which will make code coverage

@saiashok28 6 ай бұрын

Really good teaching. Thanks for sharing this video.

@ajithak.s.5224 2 жыл бұрын

Simple and precise illustration. Thank you John. Probably including parametrized junits supported in Junit5 would be better.

@henryicruise860 2 жыл бұрын

I've always been scared of Testing, thanks to this video, I feel quite comfortable with it now.

@Roshni1406 11 ай бұрын

Hey John Thank you so much for this video , you were just explain the basic unit testing in a simple way. This is a great video for beginners.👍

@illegalgiant_ Жыл бұрын

needed a refresher as i apply to sdet jobs. excellent clear stuff. thanks.

@clublulu399 2 жыл бұрын

Learning Hamcrest is in my opinion another essential library to have a good understanding of. Hamcrest library makes asserting test cases more flexible & intuitive

@saravannanponmudi3091 2 жыл бұрын

Can you do a video about Heap sort and also Time complexities?? Thank you!!!

@lauraluo7242 5 ай бұрын

U are amazing bro. For one video, I understand Unit testing.

@amiraliazimi6355 2 жыл бұрын

It was a good thing, thank you

@ribamiltombezerradelima3483 Жыл бұрын

Wow! Thank you so much! Your video is really helpful and engaging! Keep it up,pal!

@brahmareddydareddy2110 5 ай бұрын

This is so nice and wonderful way of teaching

@lqrock5438 2 жыл бұрын

Hey, first of all, a huge thank you for making these videos! they're great help to me and anyone that is studying and learning java on their own or even in school but need more to understand everything better. Also, I wanted to ask if you have any plans about making a video of how to use an API. I do know it's very simple to look it up in the internet, but your videos are very clear and easy to understand so it would definitely help me a ton! thanks in advance:)

@theblindprogrammer 2 жыл бұрын

I am just curious, what kind of an API are you looking for? Are you looking for KZfaq API or Twitter API? If so, let me know I might attempt it showing you how, I am not as good as John (obviously), but I can try.

@lqrock5438 2 жыл бұрын

@@theblindprogrammer I was looking for a more general view of it and overall how it works, I have an idea of the process as I studied it in python a year ago in university and even though I can't remember it very well now, if it's anything like python, it should be pretty simple to get into. I practice java by doing small to medium projects and every time I try to implement something new that I've studied into my project, and I'm feeling API's would be a nice addition!

@theblindprogrammer 2 жыл бұрын

@@lqrock5438 Yeah, calling APIs in Java is similar to python except in Java, it is a lot more verbose than needed. You can try it with news APIs.

@tarifadib 3 ай бұрын

thank you, i was able to create and test individual test cases with this video.

@lekhanh9085 2 жыл бұрын

Thanks John, I understood the basics of JUnit test in Java through your easy to understand examples. 😊

@tarikuasfaw6405 2 жыл бұрын

Wow I pretty much appreciate you John I am so happy to get your channel

@nyizeya99 2 жыл бұрын

Your contents are really helping

@kemiles Жыл бұрын

Appreciate you and this channel ... would love to see you cover mockito!

@olemato9460 2 жыл бұрын

I'll pass a string for ut algos to pick up John. He deserves million subs.

@gasynormand8371 2 жыл бұрын

I actually liked the video even i did not started to watch it yet. I wanted this video to come so much. Thank you

@CodingWithJohn 2 жыл бұрын

Hope it lives up to your expectations!

@AkshayDubey-fj7zj Жыл бұрын

Thanks a lot!. I wish you could create a video on Unit Testing for Spring Boot Application as well in near future

@brenodelgado1128 2 жыл бұрын

Hey John, congrats for your content. It's really clarefull and understood. Thanks from Brazil, let's keep coding.

@dev_project2012 7 ай бұрын

very good explanation , I will use more and more unit test

@kakapyksid 10 ай бұрын

whenever you have covered a topic, you have become my go-to guy to learn new things. It would be awesome if you covered mocking frameworks as well like Mockito which are probably unavoidable for a developer.

@melbali7828 2 жыл бұрын

John you are the best of the best. Keep it up and would like to see some Spring boot tutorials. Many Thanks

@oeufleau8543 2 жыл бұрын

About time you started using intellij

@jp77355 Жыл бұрын

TY!, the exception part was the best in the video!

@sunruiheng4255 Жыл бұрын

Awesome overview and introduction to JUnit, thanks!

@trexsupreme 2 жыл бұрын

Your videos are GOD SENT! As a person that just started their career as a Java Engineer, I thank you. Keep up the good work.

@theblindprogrammer 2 жыл бұрын

Keep at it, Java is really nice language.

@shukria485 2 жыл бұрын

Did you learn byyourself? I'm on that journey

@theblindprogrammer 2 жыл бұрын

@@shukria485 Yes, I am self taught. Java is not that difficult language to learn if you spend the time to learn it, if you have any questions about Java, let me know, I will help you if I can. Good luck.

@shukria485 2 жыл бұрын

@@theblindprogrammer that's awesome thank you so much.

@alexanderanastasiadis9284 2 жыл бұрын

Hi John , you are the reason who i love the Java. Every video is incredible understandable. Thanks a lot 😎

@user-ie9yw4wr2j 4 ай бұрын

Thanks!!! Eezy tutorial on unit testing

@TomAinsworth94 Жыл бұрын

Awesome vid John, thanks for going into so much detail in an actual use case!

@mateovansweevelt5257 2 жыл бұрын

Hell yea IntelliJ

@user-wf2xk7vz4l 4 ай бұрын

John never misses!

@simonandris4730 7 ай бұрын

That was very informative . Thanks for sharing your knowledge with us

@iamhassell 2 жыл бұрын

Great intro to unit testing John, awesome! Thanks!

@adityakeshan8176 2 жыл бұрын

Gold every minute of it

@dipalisavaliya295 Жыл бұрын

very nicely explained in short time and covered very good scenarios!! Thanks for your efforts :)

@sirfranciscanadianbacon1468 2 жыл бұрын

That was so well described. Very very helpful. Your videos are also produced very well.

@umiskan5819 11 ай бұрын

Great explanation! Great work! Simple and to the point Thank you!

@dougeighteenfifty980 2 жыл бұрын

Nice intro to unit tests! An intermediate one about Mockito would be an excellent progression.

@patricksolomon1923 Жыл бұрын

John, this video was excellent

@bbaekkhyyunne_4750 7 ай бұрын

very clear with thinking procedures

@mohamed-alimessedi3 Жыл бұрын

Thank you very much for sharing this in such a clear way.

@shaharts8333 5 ай бұрын

Good starter video for unit testing

@jaaeamor7901 Жыл бұрын

Awesome video! Thanks for posting!

@seanwagner3917 Жыл бұрын

Easy to follow, comprehensive from my beginner's point of view, and to the point. Do you recommend someone else's deeper dive into unit testing specifically, or say (integration) testing more generally? Thank you. Oh yes: subscribed.