Artem Zakharchenko

Learn how to use Vitest’s defaults to eliminate extra configuration and prevent flaky results, letting you write reliable tests with less effort.

Incredible Vitest Defaults

Learn advanced Vitest patterns—custom fixtures, matchers, and performance tuning—to craft faster, more effective test experiences.

Advanced Vitest Patterns

Learn how disposable objects solve test cleanup problems in flat testing. Use TypeScript's using keyword to ensure reliable resource disposal in tests.

Better Test Setup with Disposable Objects  

Test UI outcomes, not API requests. Mock network calls in setup, but assert on what users actually see and experience, not implementation details.

Do NOT Assert on Requests (Do This Instead)

Test React components in real browsers with Vitest! Say goodbye JSDOM’s limits and catch bugs users actually face. Real tests, real results—start now!

React Component Testing with Vitest

A deep dive into Testing Library's .toBeVisible() and .toBeInTheDocument() matchers, exploring their differences, use cases, and best practices

.toBeVisible() or .toBeInTheDocument()?

Explore how JSDOM's browser simulation works, and learn front-end testing approaches using Vitest Browser Mode for direct browser testing and native APIs

Why I Won’t Use JSDOM

Understand the key differences between mock state management methods: mockClear(), mockReset(), and mockRestore(). Write clean test states.

The Difference Between Clearing, Resetting, and Restoring Mocks

There can be a lot of confusion and doubt when it comes to writing tests. Answering this simple question may help clear a lot of it out.

Writing Tests That Fail

Learn to mock functions, time, globals, network, and modules. Practice real-world scenarios using Vitest to write effective and maintainable tests.

Mocking Techniques in Vitest

Learn how to test time-dependent side effects that should not happen. Avoid false positives by using inverse assertions.

Inverse Assertions

Flaky tests undermine trust. Use the S.M.A.R.T. framework: Skip, Mitigate, Assess, Rewrite, Throw away, to manage and fix them effectively.

Be S.M.A.R.T. About Flaky Tests

Learn automated testing essentials: prepare code, execute actions, verify outcomes. Discover the importance of mocking and setting proper test boundaries.

What Is A Test Boundary?

Learn what testability means, how it relates to code complexity, and why it's essential for effective testing. 








Good Code, Testable Code

In the Testing Fundamentals workshop, you will learn testing principles, framework structure, async handling, and more by building a mini testing-framework!

Testing Fundamentals

Artem Zakharchenko presents MSW's WebSocket support, enabling mock-first development for better control and real-time testing.

Mocking WebSockets with MSW

Have a better understanding about the explicit and implicit assertions now, and perhaps even have a test or two in mind to improve.

Implicit Assertions

Dive into the contentious world of code coverage. Learn its nuances, pitfalls, and practical applications for modern web app testing

Making Use of Code Coverage

Explore the analogy between learning human anatomy and writing code tests, emphasizing a universal three-step structure: Setup, Action, and Assertion.

Anatomy of a Test

Discover the importance of well-named test cases and learn five tips to help improve your test naming strategy in JavaScript.

How to Write Better Test Names

Learn about The Golden Rule of Assertions that helps pinpoint good tests from bad ones.

The Golden Rule of Assertions

Discover the true essence of automated testing and the difference between an implementation and intention.

Resources