affaan-m--everything-claude-code/rules/react-native/testing.md

paths

paths
**/*.ts **/*.tsx

React Native / Expo Testing

This file extends common/testing.md with React Native / Expo specific content. Coverage target and TDD workflow are inherited from common/testing.md (80% minimum, RED-GREEN-REFACTOR).

Tooling

Layer	Tool
Unit / component	Jest + @testing-library/react-native (via jest-expo preset)
Hooks	@testing-library/react-native renderHook
E2E	Maestro (recommended, simple YAML flows) or Detox
Type safety	tsc --noEmit in CI

Component Tests

• Query by accessible role/label/text, not by testID unless necessary — this also enforces accessibility.
• Assert on user-visible behavior, not implementation details.
• Follow Arrange-Act-Assert.

import { render, screen, fireEvent } from '@testing-library/react-native'

test('calls onSelect with the user id when pressed', () => {
  const onSelect = jest.fn()
  render(<UserCard user={{ id: '1', email: 'a@b.com' }} onSelect={onSelect} />)

  fireEvent.press(screen.getByText('a@b.com'))

  expect(onSelect).toHaveBeenCalledWith('1')
})

Mocking

• Mock Expo SDK modules (camera, location, notifications, secure-store) at the test boundary.
• Wrap components that use TanStack Query in a QueryClientProvider with a fresh client per test.
• Mock navigation (expo-router) so screens render in isolation.

E2E

• Cover critical flows only: auth, primary navigation, core transactions.
• Run E2E on CI against a built app (EAS Build) before release.

What to test first

Use the tdd-guide agent proactively for new features: write a failing test that captures the behavior, then implement.