init.spec.ts

// Polyfills
import 'core-js/es6/symbol';
import 'core-js/es6/object';
import 'core-js/es6/function';
import 'core-js/es6/parse-int';
import 'core-js/es6/parse-float';
import 'core-js/es6/number';
import 'core-js/es6/math';
import 'core-js/es6/string';
import 'core-js/es6/date';
import 'core-js/es6/array';
import 'core-js/es6/regexp';
import 'core-js/es6/map';
import 'core-js/es6/weak-map';
import 'core-js/es6/set';
import 'core-js/es6/reflect';
import 'core-js/es7/reflect';
import '@webcomponents/webcomponentsjs/custom-elements-es5-adapter';
import '@webcomponents/webcomponentsjs/webcomponents-bundle';
import 'zone.js/dist/zone';
import 'zone.js/dist/long-stack-trace-zone';
import 'zone.js/dist/proxy.js';
import 'zone.js/dist/sync-test';
import 'zone.js/dist/jasmine-patch';
import 'zone.js/dist/async-test';
import 'zone.js/dist/fake-async-test';

import { getTestBed } from '@angular/core/testing';
import {
  BrowserDynamicTestingModule,
  platformBrowserDynamicTesting
} from '@angular/platform-browser-dynamic/testing';

let karmaStyles: Element[];

beforeAll(() => {
  karmaStyles = Array.from(
    document.querySelectorAll('style,link[rel=stylesheet]')
  );
  getTestBed().initTestEnvironment(
    BrowserDynamicTestingModule,
    platformBrowserDynamicTesting()
  );
});

afterEach(() => {
  Array.from(document.querySelectorAll('style,link[rel=stylesheet]')).forEach(
    style => {
      if (karmaStyles.indexOf(style) === -1) {
        style.parentNode!.removeChild(style);
      }
    }
  );

  karmaStyles.forEach(style => {
    if (!style.parentNode) {
      document.head!.appendChild(style);
    }
  });
});