 expect: 'visible'},
  {at: 0.1, expect: 'visible'},
  {at: 0.9, expect: 'visible'},
  {at: 1, expect: 'hidden'},
  {at: 1.5, expect: 'hidden'},
]);

test_interpolation({
  property: 'content-visibility',
  from: 'hidden',
  to: 'visible',
  // transition:all is not supposed to allow content-visibility to be transitioned.
  'CSS Transitions with transition: all': alwaysVisible,
}, [
  {at: -1, expect: 'hidden'},
  {at: 0, expect: 'hidden'},
  {at: 0.1, expect: 'visible'},
  {at: 0.9, expect: 'visible'},
  {