.attr matcher unexpected changes subject

[SevenOutman]

The following assertion with Chai .and chain should work

expect(container.firstChild)
  .to.have.attr('role', 'menubar')
  .and.to.have.attr('aria-orientation', 'vertical');

But it throws

TypeError: el.getAttribute is not a function

[nathanboktae]

Yes that is odd. Changing the subject to the attribute isn't interesting.