},
  {at: 0.25, expect: 'rotateZ(65deg)'},
  {at: 0.5, expect: 'rotateZ(70deg)'},
  {at: 0.75, expect: 'rotateZ(75deg)'},
  {at: 1, expect: 'rotateZ(80deg)'},
  {at: 1.5, expect: 'rotateZ(90deg)'},
]);

// When testing rotate functions in isolation, the additive and accumulation
// behaviors are functionally identical. This test includes a skew to ensure
// both methods are implemented; add should append the from/to after the skew.
test_composition({
  property: 'transform',
  underlying: 'rotate(45deg) ske