Test Helpers

vitest-native ships a small set of helpers for controlling device state inside a test — platform, dimensions, color scheme, and native modules. Import them from vitest-native/helpers.

import {
  setPlatform,
  setDimensions,
  setColorScheme,
  mockNativeModule,
  resetAllMocks,
} from 'vitest-native/helpers'

setPlatform(os)

Switch the platform for a test. Affects Platform.OS and platform-specific behavior.

setPlatform('android')

setDimensions(dimensions)

Override the screen dimensions reported by Dimensions and useWindowDimensions.

setDimensions({ width: 768, height: 1024 })

setColorScheme(scheme)

Switch the color scheme reported by Appearance and useColorScheme.

setColorScheme('dark')

mockNativeModule(name, impl)

Provide a mock implementation for a native module.

mockNativeModule('MyNativeModule', {
  getValue: () => Promise.resolve(42),
  doSomething: () => {},
})

resetAllMocks()

Reset everything back to defaults — iOS, 390×844, light mode — and clear all spies. Call it in an afterEach to keep tests isolated:

import { afterEach } from 'vitest'
import { resetAllMocks } from 'vitest-native/helpers'

afterEach(() => resetAllMocks())

This also resets the Keyboard and AppState helper state described below.

Keyboard & AppState helpers

The Keyboard and AppState mocks include internal helpers for simulating state changes, useful for testing listeners:

import { Keyboard, AppState } from 'react-native'

// Simulate keyboard show/hide (fires keyboardDidShow / keyboardDidHide listeners)
;(Keyboard as any)._show(336) // height in pixels
;(Keyboard as any)._hide()

// Simulate app state change (fires 'change' listeners)
;(AppState as any)._setState('background')

These are reset automatically by resetAllMocks().

Next: jest-compat Layer or the API Coverage reference.