 },
                  { currentTime: 1249, progress: 1 },
                  { currentTime: 1250, progress: 0 },
                  { currentTime: 1749, progress: 0 },
                  { currentTime: 1750, progress: 1 },
                  { currentTime: 2000, progress: 1 },
                  { currentTime: 2500, progress: 1 }
                ]
  },
];

for (const options of gStepTimingFunctionTests) {
  test(t => {
    const target = createDiv(t);
    const animation = target.animate(null, options.effect);
 