text: import { FullscreenButton } from "../../Source/Cesium.js";
  
  describe("Widgets/FullscreenButton/FullscreenButton", function () {
    it("constructor sets default values", function () {
      var fullscreenButton = new FullscreenButton(document.body);
      expect(fullscreenButton.container).toBe(document.body);
      expect(fullscreenButton.viewModel.fullscreenElement).toBe(document.body);
      expect(fullscreenButton.isDestroyed()).toEqual(false);
      fullscreenButton.destroy();
      expect(fullscreenButton.isDestroyed()).toEqual(true);
    });
  
    it("constructor sets expected values", function () {
      var testElement = document.createElement("span");
      var fullscreenButton = new FullscreenButton(document.body, testElement);
      expect(fullscreenButton.container).toBe(document.body);
      expect(fullscreenButton.viewModel.fullscreenElement).toBe(testElement);
      fullscreenButton.destroy();
    });
  
    it("constructor works with string id container", function () {
      var testElement = document.createElement("span");
      testElement.id = "testElement";
      document.body.appendChild(testElement);
      var fullscreenButton = new FullscreenButton("testElement");
      expect(fullscreenButton.container).toBe(testElement);
      document.body.removeChild(testElement);
      fullscreenButton.destroy();
    });
  
    it("throws if container is undefined", function () {
      expect(function () {
        return new FullscreenButton(undefined);
      }).toThrowDeveloperError();
    });
  
    it("throws if container string is undefined", function () {
      expect(function () {
        return new FullscreenButton("testElement");
      }).toThrowDeveloperError();
    });
  });
  