217 lines
8 KiB
JavaScript
217 lines
8 KiB
JavaScript
// Here's how waitForNotification works:
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//
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// - myTestFunction0()
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// - waitForNotification(myTestFunction1)
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// - requestAnimationFrame()
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// - Modify DOM in a way that should trigger an IntersectionObserver callback.
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// - BeginFrame
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// - requestAnimationFrame handler runs
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// - Second requestAnimationFrame()
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// - Style, layout, paint
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// - IntersectionObserver generates new notifications
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// - Posts a task to deliver notifications
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// - Task to deliver IntersectionObserver notifications runs
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// - IntersectionObserver callbacks run
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// - Second requestAnimationFrameHandler runs
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// - step_timeout()
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// - step_timeout handler runs
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// - myTestFunction1()
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// - [optional] waitForNotification(myTestFunction2)
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// - requestAnimationFrame()
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// - Verify newly-arrived IntersectionObserver notifications
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// - [optional] Modify DOM to trigger new notifications
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//
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// Ideally, it should be sufficient to use requestAnimationFrame followed
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// by two step_timeouts, with the first step_timeout firing in between the
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// requestAnimationFrame handler and the task to deliver notifications.
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// However, the precise timing of requestAnimationFrame, the generation of
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// a new display frame (when IntersectionObserver notifications are
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// generated), and the delivery of these events varies between engines, making
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// this tricky to test in a non-flaky way.
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//
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// In particular, in WebKit, requestAnimationFrame and the generation of
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// a display frame are two separate tasks, so a step_timeout called within
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// requestAnimationFrame can fire before a display frame is generated.
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//
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// In Gecko, on the other hand, requestAnimationFrame and the generation of
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// a display frame are a single task, and IntersectionObserver notifications
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// are generated during this task. However, the task posted to deliver these
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// notifications can fire after the following requestAnimationFrame.
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//
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// This means that in general, by the time the second requestAnimationFrame
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// handler runs, we know that IntersectionObservations have been generated,
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// and that a task to deliver these notifications has been posted (though
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// possibly not yet delivered). Then, by the time the step_timeout() handler
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// runs, these notifications have been delivered.
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//
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// Since waitForNotification uses a double-rAF, it is now possible that
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// IntersectionObservers may have generated more notifications than what is
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// under test, but have not yet scheduled the new batch of notifications for
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// delivery. As a result, observer.takeRecords should NOT be used in tests:
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//
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// - myTestFunction0()
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// - waitForNotification(myTestFunction1)
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// - requestAnimationFrame()
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// - Modify DOM in a way that should trigger an IntersectionObserver callback.
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// - BeginFrame
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// - requestAnimationFrame handler runs
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// - Second requestAnimationFrame()
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// - Style, layout, paint
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// - IntersectionObserver generates a batch of notifications
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// - Posts a task to deliver notifications
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// - Task to deliver IntersectionObserver notifications runs
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// - IntersectionObserver callbacks run
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// - BeginFrame
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// - Second requestAnimationFrameHandler runs
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// - step_timeout()
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// - IntersectionObserver generates another batch of notifications
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// - Post task to deliver notifications
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// - step_timeout handler runs
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// - myTestFunction1()
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// - At this point, observer.takeRecords will get the second batch of
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// notifications.
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function waitForNotification(t, f) {
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return new Promise(resolve => {
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requestAnimationFrame(function() {
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requestAnimationFrame(function() {
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let callback = function() {
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resolve();
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if (f) {
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f();
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}
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};
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if (t) {
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t.step_timeout(callback);
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} else {
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setTimeout(callback);
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}
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});
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});
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});
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}
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// If you need to wait until the IntersectionObserver algorithm has a chance
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// to run, but don't need to wait for delivery of the notifications...
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function waitForFrame(t, f) {
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return new Promise(resolve => {
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requestAnimationFrame(function() {
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t.step_timeout(function() {
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resolve();
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if (f) {
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f();
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}
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});
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});
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});
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}
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// The timing of when runTestCycle is called is important. It should be
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// called:
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//
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// - Before or during the window load event, or
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// - Inside of a prior runTestCycle callback, *before* any assert_* methods
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// are called.
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//
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// Following these rules will ensure that the test suite will not abort before
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// all test steps have run.
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//
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// If the 'delay' parameter to the IntersectionObserver constructor is used,
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// tests will need to add the same delay to their runTestCycle invocations, to
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// wait for notifications to be generated and delivered.
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function runTestCycle(f, description, delay) {
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async_test(function(t) {
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if (delay) {
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step_timeout(() => {
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waitForNotification(t, t.step_func_done(f));
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}, delay);
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} else {
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waitForNotification(t, t.step_func_done(f));
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}
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}, description);
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}
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// Root bounds for a root with an overflow clip as defined by:
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// http://wicg.github.io/IntersectionObserver/#intersectionobserver-root-intersection-rectangle
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function contentBounds(root) {
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var left = root.offsetLeft + root.clientLeft;
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var right = left + root.clientWidth;
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var top = root.offsetTop + root.clientTop;
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var bottom = top + root.clientHeight;
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return [left, right, top, bottom];
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}
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// Root bounds for a root without an overflow clip as defined by:
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// http://wicg.github.io/IntersectionObserver/#intersectionobserver-root-intersection-rectangle
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function borderBoxBounds(root) {
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var left = root.offsetLeft;
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var right = left + root.offsetWidth;
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var top = root.offsetTop;
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var bottom = top + root.offsetHeight;
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return [left, right, top, bottom];
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}
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function clientBounds(element) {
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var rect = element.getBoundingClientRect();
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return [rect.left, rect.right, rect.top, rect.bottom];
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}
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function rectArea(rect) {
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return (rect.left - rect.right) * (rect.bottom - rect.top);
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}
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function checkRect(actual, expected, description, epsilon = 0) {
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if (!expected.length)
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return;
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assert_approx_equals(actual.left, expected[0], epsilon, description + '.left');
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assert_approx_equals(actual.right, expected[1], epsilon, description + '.right');
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assert_approx_equals(actual.top, expected[2], epsilon, description + '.top');
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assert_approx_equals(actual.bottom, expected[3], epsilon, description + '.bottom');
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}
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function checkLastEntry(entries, i, expected, epsilon = 0) {
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assert_equals(entries.length, i + 1, 'entries.length');
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if (expected) {
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checkRect(
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entries[i].boundingClientRect, expected.slice(0, 4),
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'entries[' + i + '].boundingClientRect', epsilon);
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checkRect(
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entries[i].intersectionRect, expected.slice(4, 8),
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'entries[' + i + '].intersectionRect', epsilon);
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checkRect(
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entries[i].rootBounds, expected.slice(8, 12),
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'entries[' + i + '].rootBounds', epsilon);
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if (expected.length > 12) {
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assert_equals(
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entries[i].isIntersecting, expected[12],
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'entries[' + i + '].isIntersecting');
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}
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}
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}
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function checkJsonEntry(actual, expected) {
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checkRect(
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actual.boundingClientRect, expected.boundingClientRect,
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'entry.boundingClientRect');
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checkRect(
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actual.intersectionRect, expected.intersectionRect,
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'entry.intersectionRect');
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if (actual.rootBounds == 'null')
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assert_equals(expected.rootBounds, 'null', 'rootBounds is null');
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else
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checkRect(actual.rootBounds, expected.rootBounds, 'entry.rootBounds');
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assert_equals(actual.isIntersecting, expected.isIntersecting);
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assert_equals(actual.target, expected.target);
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}
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function checkJsonEntries(actual, expected, description) {
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test(function() {
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assert_equals(actual.length, expected.length);
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for (var i = 0; i < actual.length; i++)
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checkJsonEntry(actual[i], expected[i]);
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}, description);
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}
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function checkIsIntersecting(entries, i, expected) {
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assert_equals(entries[i].isIntersecting, expected,
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'entries[' + i + '].target.isIntersecting equals ' + expected);
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}
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