Test Lightning Web Components

Jest is a powerful tool with rich features for writing JavaScript tests. Use Jest to write unit tests for all of your Lightning web components.

Run Jest tests at the command line or (with some configuration) within your IDE. Jest tests don’t run in a browser or connect to an org, so they run fast. When run in “watch mode” they give you immediate feedback while you’re coding. Jest tests work only with Lightning web components, they don’t work with Aura components.

Write Jest tests to:

  • Test a component in isolation
  • Test a component’s public API (@api properties and methods, events)
  • Test basic user interaction (clicks)
  • Verify the DOM output of a component
  • Verify that events fire when expected

The lwc-recipes repo is filled with Jest tests. Look for Jest tests in the __tests__ folders within the Lightning web components in force-app/main/default/lwc.

Tip

See Also

Get Started
Create Lightning Web Components
Work with Lightning Base Components
Communicate with Events
Work with Salesforce Data
Develop Secure Code
Use Components in Salesforce Targets
Use Components Outside Salesforce with Lightning Out 2.0
Aura Coexistence
Migrate Aura Components
Debug Lightning Web Components
Test Lightning Web Components
Install Jest
Run Jest Tests
Debug Jest Tests
Write Jest Tests
Write Jest Tests for Wire Service
End-to-End Tests
Jest Test Patterns
Improve Performance
Use DX MCP Tools for LWC (Beta)
LWC API Modules
Reference