message: PanelHeader: allow to be fixed for VKCOM platform
diff: import { baselineComponent } from '../../testing/utils';
  +import { render } from '@testing-library/react';
  import PanelHeader from './PanelHeader';
  +import ConfigProvider from '../ConfigProvider/ConfigProvider';
  +import { Platform } from '../../lib/platform';
  describe('PanelHeader', () => {
  baselineComponent(PanelHeader);
  +
  + it('resolves isFixed if fixed prop if it passed', () => {
  + const { container, rerender } = render(<PanelHeader fixed />);
  + expect((container.firstChild as HTMLElement).classList.contains('PanelHeader--fixed')).toEqual(true);
  + rerender(<PanelHeader fixed={false} />);
  + expect((container.firstChild as HTMLElement).classList.contains('PanelHeader--fixed')).toEqual(false);
  + });
  +
  + it('resolves isFixed if fixed prop is undefined', () => {
  + const { container } = render(<PanelHeader />);
  + expect((container.firstChild as HTMLElement).classList.contains('PanelHeader--fixed')).toEqual(true);
  + });
  +
  + it('resolves isFixed if platform is VKCOM', () => {
  + const { container, rerender } = render(
  + <ConfigProvider platform={Platform.VKCOM}>
  + <PanelHeader />
  + </ConfigProvider>,
  + );
  +
  + expect((container.firstChild as HTMLElement).classList.contains('PanelHeader--fixed')).toEqual(false);
  +
  + rerender(
  + <ConfigProvider platform={Platform.VKCOM}>
  + <PanelHeader fixed={true} />
  + </ConfigProvider>,
  + );
  +
  + expect((container.firstChild as HTMLElement).classList.contains('PanelHeader--fixed')).toEqual(true);
  + });
  });
  