Testing

Unit & partial frontend integration testing

• Jest
  • The go-to framework for testing React components, but can also be used to test regular JS.
  • If you use create-react-app, this is included.
  • Provides snapshot and DOM testing.
• testing-library
  • The current recommendation for F/E unit testing, testing-library always renders components in full and makes assertions against the resulting DOM in order to most accurately capture an actual user experience
• Enzyme
  • Allows you to assert and manipulate rendered components with jQuery-like selectors.
  • More useful for testing implementations of React class components, Enzyme can make assertions against React props and state, and instances of class components

Writing Tests

• Each React component should have a test.
  • At minimum, does the component render?
  • Container components have logic in them, and that logic should be tested.

E2E & Browser Testing

• We use Cypress for most browser testing with both Chrome and headless Chrome.

Visual Regression Testing

• We use Happo for cloud-based visual regression testing