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.

test

Milly
Vienna, Austria

Intermediate

test

Milly
Vienna, Austria

Intermediate

Matching moments

Why developers often view unit testing as a chore
00:58 MIN

Why developers often view unit testing as a chore

Test-reduction - Doing more with less

Writing unit tests for specific accessibility concerns
11:17 MIN

Writing unit tests for specific accessibility concerns

Accessibility Test Driven Development

Summary of key trends in modern JavaScript testing
26:41 MIN

Summary of key trends in modern JavaScript testing

The 2025 State of JavaScript Testing

Identifying the most common pain points in JavaScript testing
00:05 MIN

Identifying the most common pain points in JavaScript testing

The 2025 State of JavaScript Testing

Recap and practical advice for testing applications
1:28:47 MIN

Recap and practical advice for testing applications

Test Driven Development with JavaScript

Reframing common complaints about JavaScript development
01:51 MIN

Reframing common complaints about JavaScript development

How to Stop Choosing JavaScript Frameworks and Start Living

Q&A on developer tooling and testing best practices
39:23 MIN

Q&A on developer tooling and testing best practices

Data Mining Accessibility

Final thoughts on unit testing as a developer's tool
25:43 MIN

Final thoughts on unit testing as a developer's tool

How Unit Testing Saved My Career

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