s', progress: null },
                  { fill: 'both', progress: 0 } ];
  for (const test of tests) {
    const anim = createDiv(t).animate(null, { delay: 1, fill: test.fill });
    assert_equals(anim.effect.getComputedTiming().progress, test.progress,
                  `Progress in before phase when using '${test.fill}' fill`);
  }
}, 'Active time in before phase');

test(t => {
  const anim = createDiv(t).animate(null, 1000);
  anim.currentTime = 500;
  assert_time_equals_literal(anim.effect.getComputedT