Update web-platform-tests to revision b'ee6da9d71d0268d7fdb04e8e5b26858f46ee0cc4'

tests/wpt/web-platform-tests/scroll-animations/scroll-timelines/testcommon.js

@@ -0,0 +1,132 @@
+'use strict';
+
+// Builds a generic structure that looks like:
+//
+// <div class="scroller">  // 100x100 viewport
+//   <div class="contents"></div>  // 500x500
+// </div>
+//
+// The |scrollerOverrides| and |contentOverrides| parameters are maps which
+// are applied to the scroller and contents style after basic setup.
+//
+// Appends the outer 'scroller' element to the document body, and returns it.
+function setupScrollTimelineTest(
+    scrollerOverrides = new Map(), contentOverrides = new Map()) {
+  let scroller = document.createElement('div');
+  scroller.style.width = '100px';
+  scroller.style.height = '100px';
+  // Hide the scrollbars, but maintain the ability to scroll. This setting
+  // ensures that variability in scrollbar sizing does not contribute to test
+  // failures or flakes.
+  scroller.style.overflow = 'hidden';
+  for (const [key, value] of scrollerOverrides) {
+    scroller.style[key] = value;
+  }
+
+  let contents = document.createElement('div');
+  contents.style.width = '500px';
+  contents.style.height = '500px';
+  for (const [key, value] of contentOverrides) {
+    contents.style[key] = value;
+  }
+
+  scroller.appendChild(contents);
+  document.body.appendChild(scroller);
+  return scroller;
+}
+
+// Helper method to calculate the current time, implementing only step 5 of
+// https://wicg.github.io/scroll-animations/#current-time-algorithm
+function calculateCurrentTime(
+    currentScrollOffset, startScrollOffset, endScrollOffset) {
+  return ((currentScrollOffset - startScrollOffset) /
+          (endScrollOffset - startScrollOffset)) *
+         100;
+}
+
+function createScroller(test) {
+  var scroller = createDiv(test);
+  scroller.innerHTML = "<div class='contents'></div>";
+  scroller.classList.add('scroller');
+  // Trigger layout run.
+  scroller.scrollTop;
+  return scroller;
+}
+
+function createScrollerWithStartAndEnd(test, orientationClass = 'vertical') {
+  var scroller = createDiv(test);
+  scroller.innerHTML =
+    `<div class='contents'>
+        <div id='start'></div>
+        <div id='end'></div>
+      </div>`;
+  scroller.classList.add('scroller');
+  scroller.classList.add(orientationClass);
+
+  return scroller;
+}
+
+function createScrollTimeline(test, options) {
+  options = options || {
+    source: createScroller(test)
+  }
+  return new ScrollTimeline(options);
+}
+
+function createScrollTimelineWithOffsets(test, startOffset, endOffset) {
+  return createScrollTimeline(test, {
+    source: createScroller(test),
+    orientation: "vertical",
+    scrollOffsets: [startOffset, endOffset]
+  });
+}
+
+function createScrollLinkedAnimation(test, timeline) {
+  return createScrollLinkedAnimationWithTiming(test, /* duration in ms*/ 1000, timeline);
+}
+
+function createScrollLinkedAnimationWithTiming(test, timing, timeline) {
+  if (timeline === undefined)
+    timeline = createScrollTimeline(test);
+  const KEYFRAMES = { opacity: [0, 1] };
+  return new Animation(
+    new KeyframeEffect(createDiv(test), KEYFRAMES, timing), timeline);
+}
+
+function assert_approx_equals_or_null(actual, expected, tolerance, name) {
+  if (actual === null || expected === null){
+    assert_equals(actual, expected, name);
+  }
+  else {
+    assert_approx_equals(actual, expected, tolerance, name);
+  }
+}
+
+function assert_percents_approx_equal(actual, expected, maxScroll,
+                                      description) {
+  // Base the tolerance on being out by up to half a pixel.
+  const tolerance = 0.5 / maxScroll * 100;
+  assert_equals(actual.unit, "percent", `'actual' unit type must be ` +
+      `'percent' for "${description}"`);
+  assert_true(actual instanceof CSSUnitValue, `'actual' must be of type ` +
+      `CSSNumberish for "${description}"`);
+  if (expected instanceof CSSUnitValue){
+    // Verify that when the expected in a CSSUnitValue, it is the correct unit
+    // type
+    assert_equals(expected.unit, "percent", `'expected' unit type must be ` +
+        `'percent' for "${description}"`);
+    assert_approx_equals(actual.value, expected.value, tolerance,
+        `values do not match for "${description}"`);
+  } else if (typeof expected, "number"){
+    assert_approx_equals(actual.value, expected, tolerance,
+        `values do not match for "${description}"`);
+  }
+}
+
+function assert_percents_equal(actual, expected, description) {
+  // Rough estimate of the default size of the scrollable area based on
+  // sizes in setupScrollTimelineTest.
+  const defaultScrollRange = 400;
+  return assert_percents_approx_equal(actual, expected, defaultScrollRange,
+                                      description);
+}