Component testing

Same testing philosophy on both platforms; the runner and rendering harness differ. Read the shared conventions, then the section for the lib you're in (derive it from the path — see the Libraries table in AGENTS.md).

Shared conventions (both platforms)

• Import test globals explicitly — do not rely on ambient globals.
• Prefer callback/handler spies for interactions and assert with toHaveBeenCalledTimes, toHaveBeenCalledWith, not.toHaveBeenCalled.
• Cover the behaviour, not the implementation: rendering, interaction, controlled state, callbacks, and the disabled state.
• Structure: a single top-level describe('<ComponentName>'). Use flat it('should …') cases for simple components; nest describe blocks by concern (Rendering, Appearances, Sizes, Interactions, States, Styling) for richer components, and it.each([...]) for variant/size matrices.
• No snapshot tests unless there's a clear reason.

React web (libs/ui-react)

Runner: Vitest + React Testing Library.

• Globals: import { describe, it, expect, vi } from 'vitest'; and import '@testing-library/jest-dom';.
• Render: import { render, screen, fireEvent } from '@testing-library/react'; — render directly with render(<Component />), no wrapper.
• Queries: prefer accessible ones (getByRole, getByLabelText, getByText); data-testid only when nothing accessible applies.
• Interactions: fireEvent for simple click/change; userEvent from @testing-library/user-event for typing / keyboard / focus.
• Spies: vi.fn().

React Native (libs/ui-rnative)

Runner: Jest + React Native Testing Library.

• Globals: import { describe, it, expect, jest } from '@jest/globals';.
• Render: render, fireEvent, screen, waitFor from @testing-library/react-native. Every render must be wrapped in a ThemeProvider — components read theme tokens, so an unwrapped render throws. Use a small TestWrapper:

import { ledgerLiveThemes } from '@ledgerhq/lumen-design-core';
import { render, fireEvent, waitFor } from '@testing-library/react-native';
import { ThemeProvider } from '../ThemeProvider/ThemeProvider';

const TestWrapper = ({ children }: { children: React.ReactNode }) => (
  <ThemeProvider themes={ledgerLiveThemes} colorScheme='dark' locale='en'>
    {children}
  </ThemeProvider>
);

• Queries: target root elements via testID; text when testID doesn't fit; getByRole for semantic elements like switches.
• Interactions: fireEvent.press, fireEvent.changeText(input, 'text'), and the low-level fireEvent(element, '<eventName>') form for non-press events (longPress, onError). Use waitFor for state that updates after an interaction.
• Spies: jest.fn().

Review checks

Rules verifiable from a diff.

Check	Applies to	Detect	Skip
Wrong runner API for the lib	both	jest.fn()/@jest/globals in a ui-react test; vi.fn()/vitest in a ui-rnative test	—
RN render not wrapped in ThemeProvider	rnative	render(<…/>) without a themed wrapper	—
data-testid/testID used where an accessible query fits	both	getByTestId on a role-bearing element	root nodes with no accessible role
Snapshot test with no justification	both	toMatchSnapshot()	intentional, commented snapshots
Missing coverage of the disabled/controlled path on an interactive component	both	no test touching disabled/controlled state	non-interactive components