px'},
  {at: 1.5, expect: 'rgb(0, 192, 0) 30px 30px 30px'},
]);

test_interpolation({
  property: 'text-shadow',
  from: 'inherit',
  to: 'green 20px 20px 20px',
}, [
  {at: -0.3, expect: 'rgb(255, 176, 0) 33px 7px 33px'},
  {at: 0, expect: 'rgb(255, 165, 0) 30px 10px 30px'},
  {at: 0.3, expect: 'rgb(179, 154, 0) 27px 13px 27px'},
  {at: 0.6, expect: 'rgb(102, 143, 0) 24px 16px 24px'},
  {at: 1, expect: 'rgb(0, 128, 0) 20px 20px 20px'},
  {at: 1.5, expect: 'rgb(0, 110, 0) 15px 25px 15px'},
]);

test_interpo