Learning React while making web games
zerocho
Free
Basic / React
4.9
(355)
17,900+
Learn React through web games. Get familiar with Classes and Hooks, and learn additional things like Context API, React Router, Webpack, and Babel.
Basic
React
In this lecture, we will show you when testing is necessary and the advantages of testing using the Jest framework. We will apply unit testing and integration testing to React, Express, etc.
716 learners
Level Basic
Course period Unlimited


Reviews from Early Learners
5.0
RyuWoong
I tried to introduce tests using Jest, but unlike the library description, there were many more difficult points than I thought. I really like this lecture because it explains only the basics and the core without any unnecessary details. I highly recommend it to anyone who wants to learn Jest from scratch! 👍
5.0
김형
As a top-tier instructor in the JavaScript field, Zerocho's lectures are like taking a healthy medicine like ginseng, as he easily and accurately explains the basics/importance/practice of Jest that you shouldn't miss.
5.0
Cliche
For those who are new to testing or have only heard of Jest but have never used it, this might be the best course. It is structured so that you can use Jest for everything from small unit tests to large integrated tests, so that you can apply it in practice. Also, any questions or concerns that you may have while using JEST are already answered in the lecture in a self-answer format, so you don't have to ask. Lastly, the curriculum list is intuitive. You don't get everything from listening to the lecture once; you have to listen to it two or three times, and this curriculum list helps us solve our questions and concerns right away. This alone is good because it takes a big step forward in solving them.
How to use Jest
How to write test code
Precautions during testing
Unit testing, integration testing
Snapshot test
With so much work to do, you're probably wondering whether you should set aside time to write software tests. You've likely seen online posts like "You absolutely must test" and "You should implement TDD (Test-Driven Development)," further deepening your concerns.
In this lecture, we'll first explain whether testing is necessary in your current situation and then demonstrate the benefits of testing through code. This isn't a lecture that forces you to test. If you feel the need for testing yourself after watching the lecture, try implementing the tests you learned in the lecture!
📌 This lecture isn't written from the perspective of insisting on testing. I hope you'll feel the need to test yourself while watching the lecture.
📌 Rather than simply introducing the testing tool APIs, we'll introduce the mindset and best practices for testing. Among the numerous Jest APIs, we'll focus on the ones most frequently used in practice.
📌 This is not a TDD course. This course teaches how to add unit and integration tests to existing React or Express code. The goal is 100% test coverage.
📌 This course assumes basic JavaScript knowledge. Rather than a tutorial, this is a hands-on course where you'll learn about various mocking techniques and feel the need for them through observing me conducting tests.

I'm wondering if I should take the test.
I've heard that testing is good, but I'm a developer who's wondering if it's worth setting aside time to do it.

Where should I start testing?
Developers who need to write test code by necessity or by company direction but are at a loss as to where to start

What is effective testing?
Developers who are writing tests but are worried about whether the tests are correct or efficient.
You will be able to set up Jest in your existing project (React, Express).
You will be able to write unit tests and integration tests for existing projects (React, Express).
With just a little bit of effort, you can achieve 100% test coverage.
This will help you decide which parts to mock.
Testing with the Visual Studio Code Jest plugin!
Achieving 100% test coverage isn't difficult (just tedious... 😊😊)
Learn about unit testing, integration testing, and E2E testing.
No more tests that fail after running them twice! Snapshot testing (aka stuffed animals) solves the problem!
Windows 11
node.js 22
Jest 29
The practice environment doesn't really matter.
Basic JavaScript syntax
Front-end experience such as React or back-end experience such as Express or Nest.js
Rather than just following along, try to apply what you learned from the lectures to your own code.
If you get stuck while testing, please ask a question along with the source code and we will think about it together.
Who is this course right for?
For those who want to try the test but don't know how to start
Anyone who feels the need for testing because bugs keep recurring
For those who are wondering if testing increases development productivity
Anyone who wants to write effective tests
Need to know before starting?
JavaScript
TypeScript (no need to be proficient)
npm
Career Verified
68,840
Learners
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Reviews
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Answers
4.8
Rating
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Courses
One of the key strengths of my courses is the Q&A support (Winner of the Inflearn Q&A King award twice). I respond to your questions within 24 hours, doing my best to help you out! I’ll answer your questions with the mindset that we are tackling the problems together!
One of the key strengths of my courses is the Q&A support. (Winner of the Inflearn Q&A King award twice) I respond to your questions within 24 hours, doing my best to help you out! You’ll feel like we’re solving the problems together.
👉ZeroCho Lectures
ZeroCho's full lecture roadmap. A complete roadmap of all my courses is available here.
– Author of Node.js Textbook, Self-Guided JavaScript by ZeroCho, Let's Get IT JavaScript, and TypeScript Textbook
– ZeroCho.com Operator
– Currently) Broadcasting development-related content on ZeroCho TV via YouTube
– Formerly) Smoretalk CTO
– Formerly) CTO of Today's Pickup (Youngest Development Team Lead at Kakao Mobility after exit to Kakao Mobility)
Author of Node.js Textbook, Self-Guided JavaScript by ZeroCho, Let's Get IT JavaScript, and TypeScript Textbook
Operator of ZeroCho.com
Currently running a YouTube channel ZeroCho TV, covering development topics
Former CTO at SmoreTalk
Former CTO at Today Pickup (acquired by Kakao Mobility, where I became the youngest lead developer)
All
53 lectures ∙ (5hr 57min)
11. Error Test
02:46
All
33 reviews
5.0
33 reviews
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Average Rating 5.0
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Average Rating 5.0
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5
For those who are new to testing or have only heard of Jest but have never used it, this might be the best course. It is structured so that you can use Jest for everything from small unit tests to large integrated tests, so that you can apply it in practice. Also, any questions or concerns that you may have while using JEST are already answered in the lecture in a self-answer format, so you don't have to ask. Lastly, the curriculum list is intuitive. You don't get everything from listening to the lecture once; you have to listen to it two or three times, and this curriculum list helps us solve our questions and concerns right away. This alone is good because it takes a big step forward in solving them.
Reviews 11
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Average Rating 5.0
Reviews 5
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Average Rating 5.0
5
I tried to introduce tests using Jest, but unlike the library description, there were many more difficult points than I thought. I really like this lecture because it explains only the basics and the core without any unnecessary details. I highly recommend it to anyone who wants to learn Jest from scratch! 👍
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