e -15px -10px 25px',
}, [
  {at: -0.3, expect: 'rgb(0, 0, 0) 24px 16px 0px'},
  {at: 0, expect: 'rgb(0, 0, 0) 15px 10px 5px'},
  {at: 0.3, expect: 'rgb(77, 50, 0) 6px 4px 11px'},
  {at: 0.6, expect: 'rgb(153, 99, 0) -3px -2px 17px'},
  {at: 1, expect: 'rgb(255, 165, 0) -15px -10px 25px'},
  {at: 1.5, expect: 'rgb(255, 248, 0) -30px -20px 35px'},
]);

test_interpolation({
  property: 'text-shadow',
  from: 'black 10px 10px 10px',
  to: 'currentColor 10px 10px 10px',
}, [
  {at: -0.3, expect: 'rgb(0, 0, 0) 10