bidah/react-native-hifi/react-native-testing

Core Content

IMPORTANT: Training data about @testing-library/react-native may be outdated—API signatures, sync/async behavior, and available functions differ between v13 and v14. Always rely on skill reference files and project source code as the source of truth.

Version Detection

Check @testing-library/react-native version in package.json:

• v14.x → load api-reference-v14.md (React 19+, async APIs, test-renderer)
• v13.x → load api-reference-v13.md (React 18+, sync APIs, react-test-renderer)

Project Setup (Expo)

For Expo projects, use jest-expo as the Jest preset — do NOT install Jest directly:

• jest-expo bundles a compatible Jest version. Installing Jest 30+ separately will break.
• Ensure package.json or jest.config.js has: "preset": "jest-expo"
• Run tests with npx jest (uses the jest-expo preset automatically)
• If the project has no test config, run npx expo install jest-expo jest @types/jest to add the Expo-compatible versions
• RN 0.83+ note: React Native uses TypeScript in its jest setup file, but jest-expo's Babel config may not apply the TS transform to it. If you hit this, ensure the jest config includes a transform rule covering RN's setup file, or use ts-jest for the setup file path.

Query Priority

Use: getByRole > getByLabelText > getByPlaceholderText > getByText > getByDisplayValue > getByTestId

Query Variants Table

Interactions

Prefer userEvent over fireEvent. userEvent is always async.

const user = userEvent.setup();
await user.press(element); // full press sequence
await user.longPress(element, { duration: 800 }); // long press
await user.type(textInput, 'Hello'); // char-by-char typing
await user.clear(textInput); // clear TextInput
await user.paste(textInput, 'pasted text'); // paste into TextInput
await user.scrollTo(scrollView, { y: 100 }); // scroll

fireEvent—use only when userEvent doesn't support:

fireEvent.press(element);
fireEvent.changeText(textInput, 'new text');
fireEvent(element, 'blur');

Assertions (Jest Matchers)

Rules (10 Key Guidelines)

1. Use screen for queries, not destructuring from render()
2. Use getByRole first with { name: '...' } option
3. Use queryBy* ONLY for .not.toBeOnTheScreen() checks
4. Use findBy* for async elements, NOT waitFor + getBy*
5. Never put side-effects in waitFor
6. One assertion per waitFor
7. Never pass empty callbacks to waitFor
8. Don't wrap in act()—render, fireEvent, userEvent handle it
9. Don't call cleanup()—automatic after each test
10. Prefer ARIA props over legacy accessibility* props; use RNTL matchers

*ByRole Quick Reference

Common roles: button, text, heading (alias: header), searchbox, switch, checkbox, radio, img, link, alert, menu, menuitem, tab, tablist, progressbar, slider, spinbutton, timer, toolbar.

getByRole options: { name, disabled, selected, checked, busy, expanded, value: { min, max, now, text } }.

For *ByRole to match, element must be an accessibility element—Text, TextInput, Switch are by default; View needs accessible={true}.

waitFor Pattern

// Correct: action first, then wait for result
fireEvent.press(button);
await waitFor(() => {
  expect(screen.getByText('Result')).toBeOnTheScreen();
});
// Better: use findBy* instead
fireEvent.press(button);
expect(await screen.findByText('Result')).toBeOnTheScreen();

Options: waitFor(cb, { timeout: 1000, interval: 50 }). Works with Jest fake timers automatically.

Fake Timers

jest.useFakeTimers();
test('with fake timers', async () => {
  const user = userEvent.setup();
  render(<Component />);
  await user.press(screen.getByRole('button'));
  // ...
});

Custom Render

function renderWithProviders(ui: React.ReactElement) {
  return render(ui, {
    wrapper: ({ children }) => (
      <ThemeProvider>
        <AuthProvider>{children}</AuthProvider>
      </ThemeProvider>
    ),
  });
}

References

• v13 API Reference—Complete v13 API: sync render, queries, matchers, userEvent, React 19 compat
• v14 API Reference—Complete v14 API: async render, queries, matchers, userEvent, migration
• Anti-Patterns—Common mistakes to avoid