James Bender

Yes, You Need to Unit Test your JavaScript. Here's How.

Stop the slow slog to the end. Learn how TDD creates a safety net, letting you build and refactor with confidence.

Yes, You Need to Unit Test your JavaScript. Here's How.
#1about 7 minutes

Why developers avoid unit testing JavaScript

Common excuses for not unit testing are addressed by framing tests as a long-term investment that prevents project slowdowns.

#2about 5 minutes

Understanding the Test-Driven Development workflow

TDD inverts the traditional development process by using specifications to write automated tests before writing the implementation code.

#3about 7 minutes

The core characteristics of a good unit test

Effective unit tests are isolated from dependencies, targeted to a single scenario, and repeatable regardless of external factors.

#4about 5 minutes

Applying the red-green-refactor TDD cycle

The core TDD loop involves writing a failing test (red), writing minimal code to pass it (green), and then improving the code's design (refactor).

#5about 2 minutes

Choosing a JavaScript testing framework: Jest vs Jasmine

Jest is recommended over Jasmine primarily for its performance benefits, as it runs tests in a multi-threaded environment.

#6about 8 minutes

Writing your first basic unit test with Jest

A live coding demonstration introduces the basic Jest syntax, including the `test`, `expect`, and `toBe` functions for a simple sum operation.

#7about 14 minutes

Live coding a Tic-Tac-Toe game using TDD

This demonstration builds a simple game engine by following the red-green-refactor cycle and using BDD-style tests with `describe` and `it`.

#8about 2 minutes

Practical next steps for adopting unit testing

Actionable advice for teams includes starting with new features, practicing daily, sharing knowledge, and measuring code coverage.

#9about 9 minutes

Audience Q&A on testing strategies

Questions from the audience are answered, covering topics like integration testing in React, handling front-end tests, and involving product teams.

Related jobs
Jobs that call for the skills explored in this talk.

Matching moments

Why developers often view unit testing as a chore
01:57 MIN

Why developers often view unit testing as a chore

Test-reduction - Doing more with less

Writing unit tests for specific accessibility concerns
03:55 MIN

Writing unit tests for specific accessibility concerns

Accessibility Test Driven Development

Summary of key trends in modern JavaScript testing
01:52 MIN

Summary of key trends in modern JavaScript testing

The 2025 State of JavaScript Testing

Identifying the most common pain points in JavaScript testing
02:56 MIN

Identifying the most common pain points in JavaScript testing

The 2025 State of JavaScript Testing

Recap and practical advice for testing applications
13:29 MIN

Recap and practical advice for testing applications

Test Driven Development with JavaScript

Overcoming the developer habit of reaching for JavaScript
05:04 MIN

Overcoming the developer habit of reaching for JavaScript

NoLoJS - Avoiding JavaScript Cruft with HTML and CSS - Aaron T. Grogg

Q&A on developer tooling and testing best practices
16:37 MIN

Q&A on developer tooling and testing best practices

Data Mining Accessibility

Final thoughts on unit testing as a developer's tool
00:50 MIN

Final thoughts on unit testing as a developer's tool

How Unit Testing Saved My Career

Featured Partners

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From learning to earning

Jobs that call for the skills explored in this talk.

Software Developer

Software Developer

Code Healers LLC
Hinesville, United States of America

Remote
€25-35K
Intermediate
React
Python
JavaScript
+2
Software Engineer

Software Engineer

Code Healers LLC
Hinesville, United States of America

Remote
€40-50K
Intermediate
Senior
PHP
.NET
React
+2