@applicaster/zapp-react-native-utils/reactHooks/layout/useDimensions/helpers/__tests__/getInitialDimensions.native.test.js

Applicaster Zapp React Native utilities package

import * as ReactNative from "react-native";
import NativeDeviceInfo from "react-native/Libraries/Utilities/NativeDeviceInfo";

const mockDimensions = {
  window: { width: 1, height: 1 },
  screen: { width: 360, height: 540 },
};

const mockDimensionsGet = jest.fn((type) => mockDimensions[type]);

ReactNative.Dimensions.get = mockDimensionsGet;

const { Platform, Dimensions } = ReactNative;

Platform.OS = "android";

const { getInitialDimensions } = require("../getInitialDimensions.native.ts");

describe("useDimensions > helpers ( native )", () => {
  beforeEach(() => {
    jest.clearAllMocks();
  });

  it("should call Dimensions.get for window context", () => {
    getInitialDimensions("window");
    expect(Dimensions.get).toHaveBeenCalled();
  });

  it("should call Dimensions.get for screen context", () => {
    getInitialDimensions("screen");
    expect(Dimensions.get).toHaveBeenCalled();
  });

  it("should call NativeDeviceInfo.getConstants for ios when width === height", () => {
    Platform.OS = "ios";

    const mockGetConstants = jest
      .spyOn(NativeDeviceInfo, "getConstants")
      .mockReturnValue({ Dimensions: mockDimensions });

    getInitialDimensions("window");

    expect(Dimensions.get).toHaveBeenCalled();
    expect(mockGetConstants).toHaveBeenCalled();
  });
});