Agent Skills: RNTL Test Writing Guide

RNTL Test Writing Guide

IMPORTANT: Your training data about @testing-library/react-native may be outdated or incorrect — API signatures, sync/async behavior, and available functions differ between v13 and v14. Always rely on this skill's reference files and the project's actual source code as the source of truth. Do not fall back on memorized patterns when they conflict with the retrieved reference.

Version Detection

Check @testing-library/react-native version in the user's package.json:

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

Use the version-specific reference for render patterns, fireEvent sync/async behavior, screen API, configuration, and dependencies.

Query Priority

Use in this order: getByRole > getByLabelText > getByPlaceholderText > getByText > getByDisplayValue > getByTestId (last resort).

Query Variants

| Variant | Use case | Returns | Async | | ------------- | ------------------------ | ----------------------------- | ----- | | getBy* | Element must exist | element instance (throws) | No | | getAllBy* | Multiple must exist | element instance[] (throws) | No | | queryBy* | Check non-existence ONLY | element instance | null | No | | queryAllBy* | Count elements | element instance[] | No | | findBy* | Wait for element | Promise<element instance> | Yes | | findAllBy* | Wait for multiple | Promise<element instance[]> | Yes |

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 the event. See version-specific reference for sync/async behavior:

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

Assertions (Jest Matchers)

Available automatically with any @testing-library/react-native import.

| Matcher | Use for | | ------------------------------------------ | ----------------------------------------- | | toBeOnTheScreen() | Element exists in tree | | toBeVisible() | Element visible (not hidden/display:none) | | toBeEnabled() / toBeDisabled() | Disabled state via aria-disabled | | toBeChecked() / toBePartiallyChecked() | Checked state | | toBeSelected() | Selected state | | toBeExpanded() / toBeCollapsed() | Expanded state | | toBeBusy() | Busy state | | toHaveTextContent(text) | Text content match | | toHaveDisplayValue(value) | TextInput display value | | toHaveAccessibleName(name) | Accessible name | | toHaveAccessibilityValue(val) | Accessibility value | | toHaveStyle(style) | Style match | | toHaveProp(name, value?) | Prop check (last resort) | | toContainElement(el) | Contains child element | | toBeEmptyElement() | No children |

Rules

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 (no fireEvent/userEvent inside)
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 (role, aria-label, aria-disabled) over legacy accessibility* props
11. Use RNTL matchers over raw prop assertions

*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, the element must be an accessibility element:

• Text, TextInput, Switch are by default
• View needs accessible={true} (or use Pressable/TouchableOpacity)

waitFor

// 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

Recommended with userEvent (press/longPress involve real durations):

jest.useFakeTimers();

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

Custom Render

Wrap providers using wrapper option:

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