function setup({ userAgent }: { userAgent: string }) {
  TestBed.overrideProvider(userAgentToken, { useValue: userAgent });

  const fixture = TestBed.createComponent(InternetExplorer11BannerComponent);
  fixture.detectChanges();

  const readBannerText = () =>
    (fixture.nativeElement as HTMLElement).textContent.trim();

  return {
    clickDismissButton() {
      const buttonDebug = fixture.debugElement.query(By.css('button'));

      buttonDebug.triggerEventHandler('click', {});
      fixture.detectChanges();
    },
    expectBannerToBeDisplayed() {
      expect(readBannerText().toLowerCase())
        .toContain('please upgrade', 'Expected banner to be displayed');
    },
    expectBannerToBeHidden() {
      expect(readBannerText()).toBe('', 'Expected banner to be hidden');
    },
  };
}