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79 changes: 27 additions & 52 deletions skills/react-native-testing/SKILL.md
Original file line number Diff line number Diff line change
@@ -1,49 +1,42 @@
---
name: react-native-testing
description: >
Write tests using React Native Testing Library (RNTL) v13 (`@testing-library/react-native`).
Write tests using React Native Testing Library (RNTL) v13 and v14 (`@testing-library/react-native`).
Use when writing, reviewing, or fixing React Native component tests.
Covers: render, screen, queries (getBy/getAllBy/queryBy/findBy), Jest matchers,
userEvent, fireEvent, waitFor, and async patterns.
Supports both React 18 (sync render) and React 19 compat (renderAsync/fireEventAsync).
Supports v13 (React 18, sync render) and v14 (React 19+, async render).
Triggers on: test files for React Native components, RNTL imports, mentions of
"testing library", "write tests", "component tests", or "RNTL".
---

# RNTL v13 Test Writing Guide
# RNTL Test Writing Guide

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**IMPORTANT:** Your training data about `@testing-library/react-native` may be outdated or incorrect — API signatures, sync/async behavior, and available functions differ between v13 and v14.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

```tsx
import { render, screen, userEvent } from '@testing-library/react-native';

jest.useFakeTimers(); // recommended when using userEvent
## Version Detection

test('description', async () => {
const user = userEvent.setup();
render(<Component />); // sync in v13 (React 18)
Check `@testing-library/react-native` version in the user's `package.json`:

const button = screen.getByRole('button', { name: 'Submit' });
await user.press(button);
- **v14.x** → load [references/api-reference-v14.md](references/api-reference-v14.md) (React 19+, async APIs, `test-renderer`)
- **v13.x** → load [references/api-reference-v13.md](references/api-reference-v13.md) (React 18+, sync APIs, `react-test-renderer`)

expect(screen.getByText('Done')).toBeOnTheScreen();
});
```
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 | `ReactTestInstance` (throws) | No |
| `getAllBy*` | Multiple must exist | `ReactTestInstance[]` (throws) | No |
| `queryBy*` | Check non-existence ONLY | `ReactTestInstance \| null` | No |
| `queryAllBy*` | Count elements | `ReactTestInstance[]` | No |
| `findBy*` | Wait for element | `Promise<ReactTestInstance>` | Yes |
| `findAllBy*` | Wait for multiple | `Promise<ReactTestInstance[]>` | Yes |
| 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

Expand All @@ -59,12 +52,12 @@ await user.paste(textInput, 'pasted text'); // paste into TextInput
await user.scrollTo(scrollView, { y: 100 }); // scroll
```

Use `fireEvent` only when `userEvent` doesn't support the event:
`fireEvent` — use only when `userEvent` doesn't support the event. See version-specific reference for sync/async behavior:

```tsx
fireEvent.press(element); // sync, onPress only
fireEvent.changeText(textInput, 'new text'); // sync, onChangeText only
fireEvent(element, 'blur'); // any event by name
fireEvent.press(element);
fireEvent.changeText(textInput, 'new text');
fireEvent(element, 'blur');
```

## Assertions (Jest Matchers)
Expand Down Expand Up @@ -103,22 +96,6 @@ Available automatically with any `@testing-library/react-native` import.
10. **Prefer ARIA props** (`role`, `aria-label`, `aria-disabled`) over legacy `accessibility*` props
11. **Use RNTL matchers** over raw prop assertions

## React 19 Compatibility (v13.3+)

For React 19 or Suspense, use async variants:

```tsx
import { renderAsync, screen, fireEventAsync } from '@testing-library/react-native';

test('async component', async () => {
await renderAsync(<SuspenseComponent />);
await fireEventAsync.press(screen.getByRole('button'));
expect(screen.getByText('Result')).toBeOnTheScreen();
});
```

Use `rerenderAsync`/`unmountAsync` instead of `rerender`/`unmount` when using `renderAsync`.

## `*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`.
Expand All @@ -130,14 +107,6 @@ 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`)

## API Reference

See [references/api-reference.md](references/api-reference.md) for complete API signatures and options for render, screen, queries, userEvent, fireEvent, Jest matchers, waitFor, renderHook, configuration, and accessibility helpers.

## Anti-Patterns Reference

See [references/anti-patterns.md](references/anti-patterns.md) for detailed examples of what NOT to do.

## waitFor

```tsx
Expand Down Expand Up @@ -184,3 +153,9 @@ function renderWithProviders(ui: React.ReactElement) {
});
}
```

## References

- [v13 API Reference](references/api-reference-v13.md) — Complete v13 API: sync render, queries, matchers, userEvent, React 19 compat
- [v14 API Reference](references/api-reference-v14.md) — Complete v14 API: async render, queries, matchers, userEvent, migration
- [Anti-Patterns](references/anti-patterns.md) — Common mistakes to avoid
96 changes: 85 additions & 11 deletions skills/react-native-testing/references/anti-patterns.md
Original file line number Diff line number Diff line change
@@ -1,17 +1,19 @@
# RNTL v13 Anti-Patterns
# RNTL Anti-Patterns

## Table of Contents

- [Wrong query variant](#wrong-query-variant)
- [Not using \*ByRole](#not-using-byrole)
- [Wrong assertions](#wrong-assertions)
- [waitFor misuse](#waitfor-misuse)
- [Unnecessary act()](#unnecessary-act)
- [fireEvent instead of userEvent](#fireevent-instead-of-userevent)
- [Destructuring render](#destructuring-render)
- [Using UNSAFE_root](#using-unsafe_root)
- [Manual cleanup](#manual-cleanup)
- [Legacy accessibility props](#legacy-accessibility-props)
- Wrong query variant
- Not using \*ByRole
- Wrong assertions
- waitFor misuse
- Unnecessary act()
- fireEvent instead of userEvent
- Destructuring render
- Using UNSAFE_root
- Manual cleanup
- Legacy accessibility props
- Forgetting to await (v14)
- Using removed APIs (v14)

## Wrong query variant

Expand Down Expand Up @@ -211,3 +213,75 @@ afterEach(() => {
// GOOD: ARIA state props
<Pressable aria-disabled aria-checked>
```

## Forgetting to await (v14)

In RNTL v14, `render`, `fireEvent`, `rerender`, `unmount`, `renderHook`, and `act` are async. Forgetting `await` causes subtle bugs where tests pass but assertions run before operations complete.

```tsx
// BAD: missing await on render (v14)
render(<Component />);
expect(screen.getByText('Hello')).toBeOnTheScreen(); // may fail intermittently

// GOOD: await render (v14)
await render(<Component />);
expect(screen.getByText('Hello')).toBeOnTheScreen();

// BAD: missing await on fireEvent (v14)
fireEvent.press(screen.getByRole('button'));
// state updates may not have flushed yet

// GOOD: await fireEvent (v14)
await fireEvent.press(screen.getByRole('button'));

// BAD: missing await on act (v14)
act(() => {
result.current.increment();
});

// GOOD: await act (v14)
await act(() => {
result.current.increment();
});
```

## Using removed APIs (v14)

These APIs exist in v13 but are removed in v14. Using them will cause import or runtime errors.

```tsx
// BAD: using renderAsync in v14 (removed — render is already async)
import { renderAsync } from '@testing-library/react-native';
await renderAsync(<Component />);

// GOOD: use render in v14
import { render } from '@testing-library/react-native';
await render(<Component />);

// BAD: using fireEventAsync in v14 (removed — fireEvent is already async)
import { fireEventAsync } from '@testing-library/react-native';
await fireEventAsync.press(button);

// GOOD: use fireEvent in v14
import { fireEvent } from '@testing-library/react-native';
await fireEvent.press(button);

// BAD: using UNSAFE_root in v14 (removed)
screen.UNSAFE_root;

// GOOD: use container or root in v14
screen.container;
screen.root;

// BAD: using concurrentRoot option in v14 (removed — always on)
render(<Component />, { concurrentRoot: false });

// GOOD: just render without concurrentRoot
await render(<Component />);

// BAD: using update() in v14 (removed)
screen.update(<Component newProp />);

// GOOD: use rerender in v14
await screen.rerender(<Component newProp />);
```
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