Merge pull request #260 from retyui/add-use-dimensions-test

Add useDimensions tests

Author: LinusU

src/useDimensions.test.ts

@@ -0,0 +1,42 @@
+import {useDimensions} from './useDimensions'
+import {act, renderHook} from '@testing-library/react-hooks'
+
+// @ts-expect-error - untyped implementation
+import RCTDeviceEventEmitter from 'react-native/Libraries/EventEmitter/RCTDeviceEventEmitter'
+
+describe('useDimensions', () => {
+  const defaultDimensionsMock = {
+    screen: {fontScale: 2, height: 1334, scale: 2, width: 750},
+    window: {fontScale: 2, height: 1334, scale: 2, width: 750},
+  }
+
+  const emitChangeDimensions = ({
+    window = defaultDimensionsMock.window,
+    screen = defaultDimensionsMock.screen,
+  }) => RCTDeviceEventEmitter.emit('didUpdateDimensions', {window, screen})
+
+  it('should return device dimensions', () => {
+    const {result} = renderHook(() => useDimensions())
+
+    expect(result.current).toEqual(defaultDimensionsMock)
+  })
+
+  it('should update dimensions when they change', () => {
+    const newWindow = {...defaultDimensionsMock.window, height: 600}
+    const {result} = renderHook(() => useDimensions())
+
+    const {height: initialHeight} = result.current.window
+
+    act(() => emitChangeDimensions({window: newWindow}))
+
+    const {height: afterUpdateHeight} = result.current.window
+
+    expect({
+      initialHeight,
+      afterUpdateHeight,
+    }).toEqual({
+      initialHeight: 1334,
+      afterUpdateHeight: 600,
+    })
+  })
+})