message: Add test for wrapper
diff: @@ -22,3 +22,8 @@ test('element is div', async () => {
  const div = await container(vlSpec);
  expect(div.tagName).toBe('DIV');
  });
  +
  +test('element is wrapper', async () => {
  + const div = await container(vlSpec);
  + expect(div.classList).toContain('vega-embed-wrapper');
  +});
  