mcpField
R
react-native-testing

react-native-testing

github.com/callstackincubatorTesting & quality1.7k55 installsUpdated 3w ago
Repository

About react-native-testing

A test-writing skill for React Native Testing Library, intended for developers writing component tests. It directs users to version-specific API references and gives query, interaction, assertion, and async-testing guidance.

Key features

  1. 01Detect RNTL version and load matching reference
  2. 02Prioritize accessible queries such as getByRole
  3. 03Prefer userEvent for interactions
  4. 04Use RNTL matchers for assertions
  5. 05Avoid common async and waitFor pitfalls

Use cases

  1. 01Writing tests against the installed RNTL version
  2. 02Testing accessible controls and user interactions
  3. 03Checking asynchronous UI updates
  4. 04Reviewing tests for common anti-patterns

Install

Copy the command and run it in a terminal.

$npx skills add https://github.com/callstackincubator/agent-skills --skill react-native-testing

After installing, type/react-native-testingin Claude Code to confirm it loaded.

Bundled files

References and scripts installed along with SKILL.md.

references/
anti-patterns.md
api-reference-v13.md
api-reference-v14.md

Details

From the project README

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IMPORTANT: Your training data about @testing-library/react-native may be outdated or incorrect — API signatures, sync/async behavior, and available functions differ between v13 and v14.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:

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

VariantUse caseReturnsAsync
getBy*Element must existelement instance (throws)No
getAllBy*Multiple must existelement instance[] (throws)No
queryBy*Check non-existence ONLYelement instance | nullNo
queryAllBy*Count elementselement instance[]No
findBy*Wait for elementPromise<element instance>Yes
findAllBy*Wait for multiplePromise<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.

MatcherUse 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

Comments

Markdown supported