STEP 1:
Dependency Updates
Dependency Updates
Step 6: Testing Updates
Open Beta Documentation Amazon offers this technical
documentation as part of a pre-release, open beta. The features described might change as Amazon receives feedback
and iterates on the features. For the most current feature information, see the latest Release
Notes.
6.1 Update jest.config.js
The transformIgnorePatterns must include @amazon-devices/react-native-kepler. The package 4.0.0 uses ES module syntax in its jest/setup.js file. Without this pattern, Jest fails with SyntaxError: Cannot use import statement outside a module.
module.exports = {
preset: 'react-native',
setupFilesAfterEnv: ['<rootDir>/jest.setup.js'],
transformIgnorePatterns: [
'node_modules/(?!((jest-)?react-native|@react-native(-community)?|@amazon-devices/react-native-kepler)|react-native-safe-area-context)',
],
};
6.2 Create jest.setup.js for TV mocks
RN 0.83 changes how mocks work in the test environment. Create a setup file with TV-appropriate mocks, such as the example below.
// jest.setup.js
/**
* Mock Dimensions API for TV platform
* Fire TV devices use 1920x1080 (Full HD) resolution with scale factor 1
*/
jest.mock('react-native/Libraries/Utilities/Dimensions', () => ({
get: jest.fn().mockReturnValue({
width: 1920,
height: 1080,
scale: 1,
fontScale: 1,
}),
addEventListener: jest.fn(),
removeEventListener: jest.fn(),
}));
/**
* Mock PixelRatio API for TV platform
* TV devices use scale factor of 1 (no pixel doubling)
*/
jest.mock('react-native/Libraries/Utilities/PixelRatio', () => ({
default: {
get: jest.fn().mockReturnValue(1),
getFontScale: jest.fn().mockReturnValue(1),
getPixelSizeForLayoutSize: jest.fn((layoutSize) => layoutSize),
roundToNearestPixel: jest.fn((layoutSize) => layoutSize),
},
}));
/**
* Mock NativeAnimatedModule — RN 0.83 calls 23 specific methods.
* Required for any test that triggers navigation animations.
*/
jest.mock('react-native/Libraries/Animated/NativeAnimatedModule', () => ({
__esModule: true,
default: {
startOperationBatch: jest.fn(),
finishOperationBatch: jest.fn(),
createAnimatedNode: jest.fn(),
updateAnimatedNodeConfig: jest.fn(),
getValue: jest.fn(),
startListeningToAnimatedNodeValue: jest.fn(),
stopListeningToAnimatedNodeValue: jest.fn(),
connectAnimatedNodes: jest.fn(),
disconnectAnimatedNodes: jest.fn(),
startAnimatingNode: jest.fn(),
stopAnimation: jest.fn(),
setAnimatedNodeValue: jest.fn(),
setAnimatedNodeOffset: jest.fn(),
flattenAnimatedNodeOffset: jest.fn(),
extractAnimatedNodeOffset: jest.fn(),
connectAnimatedNodeToView: jest.fn(),
disconnectAnimatedNodeFromView: jest.fn(),
restoreDefaultValues: jest.fn(),
dropAnimatedNode: jest.fn(),
addAnimatedEventToView: jest.fn(),
removeAnimatedEventFromView: jest.fn(),
addListener: jest.fn(),
removeListeners: jest.fn(),
},
}));
6.3 Fix Jest mocks for .default exports
RN 0.83 changes many internal modules to use export default. Existing Jest mocks that return plain objects without a .default property break silently, where components receive undefined at runtime.
Symptom Cannot read properties of undefined (reading 'create') across multiple test suites.
Affected modules
react-native/Libraries/StyleSheet/StyleSheetreact-native/Libraries/StyleSheet/flattenStylereact-native/Libraries/EventEmitter/NativeEventEmitterreact-native/Libraries/Utilities/Platformreact-native/Libraries/Utilities/Dimensionsreact-native/Libraries/Utilities/PixelRatioreact-native/Libraries/Utilities/useWindowDimensionsreact-native/Libraries/BatchedBridge/NativeModules
Fix pattern for object-type exports
// ❌ BEFORE (breaks in RN 0.83)
jest.mock('react-native/Libraries/StyleSheet/StyleSheet', () => ({
create: (styles) => styles,
flatten: jest.fn(),
}));
// ✅ AFTER — include __esModule and default
jest.mock('react-native/Libraries/StyleSheet/StyleSheet', () => {
const impl = {
create: (styles) => styles,
flatten: jest.fn(),
};
return { __esModule: true, default: impl, ...impl };
});
Fix pattern for function-type exports:
// For function-type default exports, return the function as default directly
jest.mock('react-native/Libraries/StyleSheet/flattenStyle', () => {
const impl = jest.fn((style) => style);
return { __esModule: true, default: impl };
});
6.4 Update test files with act() wrapping
React 19 requires state updates in tests to be wrapped in act(), such as the example below.
// ❌ BEFORE (RN 0.72)
import 'react-native';
import React from 'react';
import App from '../App';
import renderer from 'react-test-renderer';
it('renders correctly', () => {
renderer.create(<App />);
});
// ✅ AFTER (RN 0.83) — using react-test-renderer directly
import React from 'react';
import ReactTestRenderer from 'react-test-renderer';
import App from '../App';
test('renders correctly', async () => {
await ReactTestRenderer.act(() => {
ReactTestRenderer.create(<App />);
});
});
@testing-library/react-native
If you use @testing-library/react-native, the testing library handles act() internally. Don't wrap render() in ReactTestRenderer.act() because this causes "Can't access .root on unmounted test renderer" errors.
// ✅ CORRECT with @testing-library/react-native
import { render, fireEvent } from '@testing-library/react-native';
test('renders correctly', () => {
const screen = render(<App />);
expect(screen).toMatchSnapshot();
});
test('handles button press', () => {
const screen = render(<App />);
fireEvent.press(screen.getByTestId('myButton'));
expect(screen).toMatchSnapshot();
});
6.5 Fix navigation stack timer leaks
If you use react-navigation__stack, its Card.tsx file uses animation setTimeout callbacks that fire after Jest tears down the test environment.
Symptom You are trying to import a file after the Jest environment has been torn down
Fix: add to affected test files
beforeEach(() => jest.useFakeTimers());
afterEach(() => {
jest.runOnlyPendingTimers();
jest.useRealTimers();
});
6.6 Fix isolatedModules type export errors
If TypeScript reports TS1205: Re-exporting a type when 'isolatedModules' is enabled requires using 'export type', update your export type like the example below.
// ❌ BEFORE
export { Cookie } from './types/CookieManagerTypes';
// ✅ AFTER
export type { Cookie } from './types/CookieManagerTypes';
6.7 Update snapshots
After all test fixes, regenerate snapshots.
# Run tests to see failures
npm test
# Update all snapshots
npm test -- -u
Review changes. Expected React 19 snapshot differences include:
- Component wrapper structure changes
- Attribute ordering differences
- Text node rendering modifications
- Async boundary updates
Use git diff to review snapshot changes before committing.
Last updated: Jul 09, 2026
