 addTo: '200px',
}, [
  {at: -0.3, expect: '120px'},
  {at: 0, expect: '150px'},
  {at: 0.5, expect: '200px'},
  {at: 1, expect: '250px'},
  {at: 1.5, expect: '300px'},
]);

test_composition({
  property: 'max-width',
  underlying: '100px',
  addFrom: '10px',
  addTo: '2px',
}, [
  {at: -0.5, expect: '114px'},
  {at: 0, expect: '110px'},
  {at: 0.5, expect: '106px'},
  {at: 1, expect: '102px'},
  {at: 1.5, expect: '98px'}, // Value clamping should happen after composition.
]);

test_composition({
  property