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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 01:47:29 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 01:47:29 +0000
commit0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d (patch)
treea31f07c9bcca9d56ce61e9a1ffd30ef350d513aa /testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout
parentInitial commit. (diff)
downloadfirefox-esr-0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d.tar.xz
firefox-esr-0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d.zip
Adding upstream version 115.8.0esr.upstream/115.8.0esr
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout')
-rw-r--r--testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/adding-only-snap-area.html55
-rw-r--r--testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/adding-snap-area-while-snapped.html66
-rw-r--r--testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/changing-scroll-snap-align.html121
-rw-r--r--testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/changing-scroll-snap-type-on-root-element.html95
-rw-r--r--testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/changing-scroll-snap-type.html96
-rw-r--r--testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/focus-element-no-snap.html51
-rw-r--r--testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/move-current-target.html116
-rw-r--r--testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/not-resnap-outside-proximity-threshold.html66
-rw-r--r--testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/remove-current-target.html65
-rw-r--r--testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/resnap-to-focused.html82
-rw-r--r--testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/snap-to-different-targets.html92
11 files changed, 905 insertions, 0 deletions
diff --git a/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/adding-only-snap-area.html b/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/adding-only-snap-area.html
new file mode 100644
index 0000000000..53141707bb
--- /dev/null
+++ b/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/adding-only-snap-area.html
@@ -0,0 +1,55 @@
+<!DOCTYPE html>
+<title>
+ Adding a new snap area when there are none should make the scroller snap to it.
+</title>
+<link rel="help" href="https://drafts.csswg.org/css-scroll-snap/#re-snap" />
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<style>
+div {
+ position: absolute;
+ margin: 0;
+}
+
+#scroller {
+ height: 500px;
+ width: 500px;
+ overflow: hidden;
+ scroll-snap-type: both mandatory;
+}
+
+#target {
+ width: 300px;
+ height: 300px;
+ top: 100px;
+ left: 100px;
+ background-color: green;
+ scroll-snap-align: start;
+}
+
+.area {
+ width: 2000px;
+ height: 2000px;
+}
+</style>
+
+<div id="scroller">
+ <div class="area"></div>
+ <div id="target"></div>
+</div>
+
+<script>
+const target = document.getElementById("target");
+const scroller = document.getElementById("scroller");
+
+test(() => {
+ scroller.removeChild(target);
+ scroller.scrollTo(0,0);
+ assert_equals(scroller.scrollTop, 0);
+ assert_equals(scroller.scrollLeft, 0);
+
+ scroller.appendChild(target);
+ assert_equals(scroller.scrollTop, 100);
+ assert_equals(scroller.scrollLeft, 100);
+}, "Adding a new snap area when there are none should make the scroller snap to it.");
+</script>
diff --git a/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/adding-snap-area-while-snapped.html b/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/adding-snap-area-while-snapped.html
new file mode 100644
index 0000000000..d26359658f
--- /dev/null
+++ b/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/adding-snap-area-while-snapped.html
@@ -0,0 +1,66 @@
+<!DOCTYPE html>
+<title>
+ Adding a new snap area while already snapped should not make the scroller snap to it.
+</title>
+<link rel="help" href="https://drafts.csswg.org/css-scroll-snap/#re-snap" />
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<style>
+div {
+ position: absolute;
+ margin: 0;
+}
+
+#scroller {
+ height: 500px;
+ width: 500px;
+ overflow: hidden;
+ scroll-snap-type: both mandatory;
+}
+
+#initial-target {
+ width: 300px;
+ height: 300px;
+ top: 100px;
+ left: 100px;
+ background-color: green;
+ scroll-snap-align: start;
+}
+
+#other-target {
+ width: 300px;
+ height: 300px;
+ top: 300px;
+ left: 300px;
+ background-color: red;
+ scroll-snap-align: start;
+}
+
+.area {
+ width: 2000px;
+ height: 2000px;
+}
+</style>
+
+<div id="scroller">
+ <div class="area"></div>
+ <div id="initial-target"></div>
+ <div id="other-target"></div>
+</div>
+
+<script>
+const initial_target = document.getElementById("initial-target");
+const other_target = document.getElementById("other-target");
+const scroller = document.getElementById("scroller");
+
+test(() => {
+ scroller.removeChild(other_target);
+ scroller.scrollTo(0,0);
+ assert_equals(scroller.scrollTop, 100);
+ assert_equals(scroller.scrollLeft, 100);
+
+ scroller.appendChild(other_target);
+ assert_equals(scroller.scrollTop, 100);
+ assert_equals(scroller.scrollLeft, 100);
+}, "Adding a new snap area while already snapped should not make the scroller snap to it.");
+</script>
diff --git a/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/changing-scroll-snap-align.html b/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/changing-scroll-snap-align.html
new file mode 100644
index 0000000000..3be68fe841
--- /dev/null
+++ b/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/changing-scroll-snap-align.html
@@ -0,0 +1,121 @@
+<!DOCTYPE html>
+<title>
+ Updating the snap alignment of a snap container's content should make the snap
+ container resnap accordingly.
+</title>
+<link rel="help" href="https://drafts.csswg.org/css-scroll-snap/#re-snap" />
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<style>
+div {
+ position: absolute;
+ margin: 0;
+}
+
+#scroller {
+ height: 200px;
+ width: 200px;
+ overflow: hidden;
+ scroll-snap-type: both mandatory;
+}
+
+#initial-target {
+ width: 300px;
+ height: 300px;
+ top: 100px;
+ left: 100px;
+ background-color: green;
+ scroll-snap-align: start;
+}
+
+#other-target {
+ width: 300px;
+ height: 300px;
+ top: 300px;
+ left: 300px;
+ background-color: red;
+ scroll-snap-align: start;
+}
+
+.area {
+ width: 2000px;
+ height: 2000px;
+}
+
+.snap-area {
+ scroll-snap-align: start !important;
+}
+</style>
+
+<div id="scroller">
+ <div class="area"></div>
+ <div id="initial-target"></div>
+ <div id="other-target"></div>
+</div>
+
+<script>
+const initial_target = document.getElementById("initial-target");
+const other_target = document.getElementById("other-target");
+const scroller = document.getElementById("scroller");
+
+function cleanup() {
+ initial_target.style.setProperty("scroll-snap-align", "start");
+ other_target.style.setProperty("scroll-snap-align", "start");
+ initial_target.removeAttribute("class");
+}
+
+test(t => {
+ t.add_cleanup(cleanup);
+ scroller.scrollTo(0,0);
+ assert_equals(scroller.scrollTop, 100);
+ assert_equals(scroller.scrollLeft, 100);
+
+ initial_target.style.setProperty("scroll-snap-align", "end");
+ // target.top + target.height - scroller.height
+ assert_equals(scroller.scrollTop, 200);
+ assert_equals(scroller.scrollLeft, 200);
+}, "Changing the current target's snap alignment should make the scroller"
++ " resnap to it even if another snap position is closer to the current offset");
+
+test(t => {
+ t.add_cleanup(cleanup);
+ scroller.scrollTo(0,0);
+ assert_equals(scroller.scrollTop, 100);
+ assert_equals(scroller.scrollLeft, 100);
+
+ initial_target.style.setProperty("scroll-snap-align", "none");
+ assert_equals(scroller.scrollTop, 300);
+ assert_equals(scroller.scrollLeft, 300);
+}, "Removing the current target's snap alignment should make the scroller"
++ " resnap to a new snap area.");
+
+test(t => {
+ t.add_cleanup(cleanup);
+ initial_target.style.setProperty("scroll-snap-align", "none");
+ other_target.style.setProperty("scroll-snap-align", "none");
+
+ scroller.scrollTo(0,0);
+ assert_equals(scroller.scrollTop, 0);
+ assert_equals(scroller.scrollLeft, 0);
+
+ initial_target.style.setProperty("scroll-snap-align", "start");
+ assert_equals(scroller.scrollTop, 100);
+ assert_equals(scroller.scrollLeft, 100);
+}, "Changing an element snap alignment from none to start should make the"
++ "scroller resnap.");
+
+test(t => {
+ t.add_cleanup(cleanup);
+ initial_target.style.setProperty("scroll-snap-align", "none");
+ other_target.style.setProperty("scroll-snap-align", "none");
+
+ scroller.scrollTo(0,0);
+ assert_equals(scroller.scrollTop, 0);
+ assert_equals(scroller.scrollLeft, 0);
+
+ initial_target.classList.add("snap-area");
+ assert_equals(scroller.scrollTop, 100);
+ assert_equals(scroller.scrollLeft, 100);
+}, "Changing an element snap alignment from none to start by adding a class"
++ " should make the scroller resnap.");
+</script>
diff --git a/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/changing-scroll-snap-type-on-root-element.html b/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/changing-scroll-snap-type-on-root-element.html
new file mode 100644
index 0000000000..c86f39b9d6
--- /dev/null
+++ b/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/changing-scroll-snap-type-on-root-element.html
@@ -0,0 +1,95 @@
+<!DOCTYPE html>
+<html>
+<title>
+ Updating the scroll-snap-type of the root element should make it resnap accordingly.
+ This is another vairant of changing-scroll-snap-type.html for the root element.
+</title>
+<link rel="help" href="https://drafts.csswg.org/css-scroll-snap/#re-snap" />
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<style>
+div {
+ position: absolute;
+ margin: 0;
+}
+
+html {
+ overflow: hidden;
+ scroll-snap-type: none;
+}
+
+#y-target {
+ width: 300px;
+ height: 300px;
+ top: 100px;
+ left: 0;
+ background-color: green;
+ scroll-snap-align: start none;
+}
+
+#x-target {
+ width: 300px;
+ height: 300px;
+ top: 0;
+ left: 100px;
+ background-color: red;
+ scroll-snap-align: none start;
+}
+
+.area {
+ width: 1000vw;
+ height: 1000vh;
+}
+</style>
+
+<div class="area"></div>
+<div id="x-target"></div>
+<div id="y-target"></div>
+
+<script>
+const x_target = document.getElementById("x_target");
+const y_target = document.getElementById("y_target");
+const scroller = document.documentElement;
+
+function cleanup() {
+ scroller.style.setProperty("scroll-snap-type", "none");
+}
+
+test(t => {
+ t.add_cleanup(cleanup);
+ scroller.scrollTo(0,0);
+ assert_equals(scroller.scrollTop, 0);
+ assert_equals(scroller.scrollLeft, 0);
+
+ scroller.style.setProperty("scroll-snap-type", "y mandatory");
+ assert_equals(scroller.scrollTop, 100);
+ assert_equals(scroller.scrollLeft, 0);
+}, "Changing the scroller's snap type to y should make it resnap on the y-axis.");
+
+test(t => {
+ t.add_cleanup(cleanup);
+ scroller.scrollTo(0,0);
+ assert_equals(scroller.scrollTop, 0);
+ assert_equals(scroller.scrollLeft, 0);
+
+ scroller.style.setProperty("scroll-snap-type", "x mandatory");
+ assert_equals(scroller.scrollLeft, 100);
+ assert_equals(scroller.scrollTop, 0);
+}, "Changing the scroller's snap type to x should make it resnap on the x-axis.");
+
+
+test(t => {
+ t.add_cleanup(cleanup);
+ scroller.scrollTo(0,0);
+ assert_equals(scroller.scrollTop, 0);
+ assert_equals(scroller.scrollLeft, 0);
+
+ scroller.style.setProperty("scroll-snap-type", "x mandatory");
+ assert_equals(scroller.scrollLeft, 100);
+ assert_equals(scroller.scrollTop, 0);
+
+ scroller.style.setProperty("scroll-snap-type", "y mandatory");
+ assert_equals(scroller.scrollTop, 100);
+}, "Changing the scroller's snap type axis should make it resnap.");
+</script>
+</html>
diff --git a/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/changing-scroll-snap-type.html b/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/changing-scroll-snap-type.html
new file mode 100644
index 0000000000..70774b3d40
--- /dev/null
+++ b/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/changing-scroll-snap-type.html
@@ -0,0 +1,96 @@
+<!DOCTYPE html>
+<title>
+ Updating the scroll-snap-type of a snap container should make it resnap accordingly.
+</title>
+<link rel="help" href="https://drafts.csswg.org/css-scroll-snap/#re-snap" />
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<style>
+div {
+ position: absolute;
+ margin: 0;
+}
+
+#scroller {
+ height: 500px;
+ width: 500px;
+ overflow: hidden;
+ scroll-snap-type: none;
+}
+
+#y-target {
+ width: 300px;
+ height: 300px;
+ top: 100px;
+ left: 0;
+ background-color: green;
+ scroll-snap-align: start none;
+}
+
+#x-target {
+ width: 300px;
+ height: 300px;
+ top: 0;
+ left: 100px;
+ background-color: red;
+ scroll-snap-align: none start;
+}
+
+.area {
+ width: 2000px;
+ height: 2000px;
+}
+</style>
+
+<div id="scroller">
+ <div class="area"></div>
+ <div id="x-target"></div>
+ <div id="y-target"></div>
+</div>
+
+<script>
+const x_target = document.getElementById("x_target");
+const y_target = document.getElementById("y_target");
+const scroller = document.getElementById("scroller");
+
+function cleanup() {
+ scroller.style.setProperty("scroll-snap-type", "none");
+}
+
+test(t => {
+ t.add_cleanup(cleanup);
+ scroller.scrollTo(0,0);
+ assert_equals(scroller.scrollTop, 0);
+ assert_equals(scroller.scrollLeft, 0);
+
+ scroller.style.setProperty("scroll-snap-type", "y mandatory");
+ assert_equals(scroller.scrollTop, 100);
+ assert_equals(scroller.scrollLeft, 0);
+}, "Changing the scroller's snap type to y should make it resnap on the y-axis.");
+
+test(t => {
+ t.add_cleanup(cleanup);
+ scroller.scrollTo(0,0);
+ assert_equals(scroller.scrollTop, 0);
+ assert_equals(scroller.scrollLeft, 0);
+
+ scroller.style.setProperty("scroll-snap-type", "x mandatory");
+ assert_equals(scroller.scrollLeft, 100);
+ assert_equals(scroller.scrollTop, 0);
+}, "Changing the scroller's snap type to x should make it resnap on the x-axis.");
+
+
+test(t => {
+ t.add_cleanup(cleanup);
+ scroller.scrollTo(0,0);
+ assert_equals(scroller.scrollTop, 0);
+ assert_equals(scroller.scrollLeft, 0);
+
+ scroller.style.setProperty("scroll-snap-type", "x mandatory");
+ assert_equals(scroller.scrollLeft, 100);
+ assert_equals(scroller.scrollTop, 0);
+
+ scroller.style.setProperty("scroll-snap-type", "y mandatory");
+ assert_equals(scroller.scrollTop, 100);
+}, "Changing the scroller's snap type axis should make it resnap.");
+</script>
diff --git a/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/focus-element-no-snap.html b/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/focus-element-no-snap.html
new file mode 100644
index 0000000000..9ec004c628
--- /dev/null
+++ b/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/focus-element-no-snap.html
@@ -0,0 +1,51 @@
+<!doctype html>
+<title>Resnap to focused element after relayout</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<style>
+
+#snapper {
+ width: 100px;
+ height: 200px;
+ overflow-x: scroll;
+ scroll-snap-type: x mandatory;
+ color: white;
+ background-color: oldlace;
+ display: flex;
+ align-items: center;
+}
+.child {
+ margin-right: 0.5rem;
+ height: 90%;
+ scroll-snap-align: start;
+ padding: 1rem;
+ display: flex;
+ align-items: center;
+ justify-content: center;
+ text-align: center;
+ width: 100px;
+ height: 100px;
+ background-color: indigo;
+}
+</style>
+
+<link rel="help" href="https://drafts.csswg.org/css-scroll-snap/#re-snap">
+
+<div id=snapper>
+ <div class="child no-snap" tabindex=-1></div>
+ <div class=child></div>
+ <div class="child" id ="focus" tabindex=-1></div>
+ <div class="child" tabindex=-1></div>
+ <div class=child></div>
+ <div class=child></div>
+</div>
+
+<script>
+
+test(t => {
+ document.getElementById("focus").focus();
+ const element = document.getElementById("snapper");
+ element.style.width = "101px";
+ assert_equals(element.scrollLeft, 0);
+});
+</script>
diff --git a/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/move-current-target.html b/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/move-current-target.html
new file mode 100644
index 0000000000..ccadc884c5
--- /dev/null
+++ b/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/move-current-target.html
@@ -0,0 +1,116 @@
+<!DOCTYPE html>
+<title>
+ Moving the current snap target should make the scroller resnap to it.
+</title>
+<link rel="help" href="https://drafts.csswg.org/css-scroll-snap/#re-snap" />
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<style>
+div {
+ position: relative;
+ margin: 0;
+}
+
+#block {
+ height: 100px;
+ width: 100px;
+}
+
+#scroller {
+ height: 500px;
+ width: 500px;
+ overflow: hidden;
+ scroll-snap-type: both mandatory;
+}
+
+#initial-target {
+ width: 300px;
+ height: 300px;
+ left: 100px;
+ top: 0;
+ transform: none;
+ background-color: green;
+ scroll-snap-align: start;
+}
+
+#other-target {
+ width: 300px;
+ height: 300px;
+ left: 300px;
+ background-color: red;
+ scroll-snap-align: start;
+}
+
+.area {
+ width: 2000px;
+ height: 2000px;
+}
+</style>
+
+<div id="scroller">
+ <div id="block"></div>
+ <div id="initial-target"></div>
+ <div id="other-target"></div>
+ <div class="area"></div>
+</div>
+
+<script>
+const initial_target = document.getElementById("initial-target");
+const other_target = document.getElementById("other-target");
+const block = document.getElementById("block");
+const scroller = document.getElementById("scroller");
+
+function cleanup() {
+ initial_target.style.setProperty("transform", "none");
+ initial_target.style.setProperty("top", "0");
+ block.style.setProperty("height", "100px");
+}
+
+test(t => {
+ t.add_cleanup(cleanup);
+ scroller.scrollTo(0,0);
+ assert_equals(scroller.scrollTop, 100);
+ assert_equals(scroller.scrollLeft, 100);
+
+ initial_target.style.setProperty("top", "300px");
+ assert_equals(scroller.scrollTop, 400);
+ assert_equals(scroller.scrollLeft, 100);
+}, "Moving the current snap target should make the scroller resnap to it.");
+
+test(t => {
+ t.add_cleanup(cleanup);
+ scroller.scrollTo(0,0);
+ assert_equals(scroller.scrollTop, 100);
+ assert_equals(scroller.scrollLeft, 100);
+
+ block.style.setProperty("height", "200px");
+ assert_equals(scroller.scrollTop, 200);
+ assert_equals(scroller.scrollLeft, 100);
+}, "Changing the layout of other elements should be able to cause resnapping to \
+the target.");
+
+test(t => {
+ t.add_cleanup(cleanup);
+ scroller.scrollTo(0,0);
+ assert_equals(scroller.scrollTop, 100);
+ assert_equals(scroller.scrollLeft, 100);
+
+ initial_target.style.setProperty("transform", "translate(0,100px)");
+ assert_equals(scroller.scrollTop, 200);
+ assert_equals(scroller.scrollLeft, 100);
+}, "Transforming the current snap target should make the scroller resnap to it.");
+
+test(t => {
+ t.add_cleanup(cleanup);
+ initial_target.style.setProperty("top", "100px");
+ scroller.scrollTo(0,0);
+ assert_equals(scroller.scrollTop, 200);
+ assert_equals(scroller.scrollLeft, 100);
+
+ initial_target.style.setProperty("transform", "translate(0,100px)");
+ initial_target.style.setProperty("top", "0");
+ assert_equals(scroller.scrollTop, 200);
+ assert_equals(scroller.scrollLeft, 100);
+}, "Applying two property changes that do not change the visual offset of the \
+target should not change the scroll offset.");
+</script>
diff --git a/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/not-resnap-outside-proximity-threshold.html b/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/not-resnap-outside-proximity-threshold.html
new file mode 100644
index 0000000000..b2c5720efb
--- /dev/null
+++ b/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/not-resnap-outside-proximity-threshold.html
@@ -0,0 +1,66 @@
+<!DOCTYPE html>
+<title>
+ Not re-snap once after a scroll operation has finished without snapping
+ because the scroll destination was outside of the snap proximity threshold.
+</title>
+<!-- This test assumes that all major browsers' default scroll-snap proximity
+ thresholds are greater than 200px. -->
+<link rel="help" href="https://drafts.csswg.org/css-scroll-snap/#re-snap" />
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1780154">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<style>
+div {
+ position: absolute;
+ margin: 0;
+}
+
+#scroller {
+ height: 600px;
+ width: 600px;
+ overflow: hidden;
+ scroll-snap-type: y proximity;
+}
+
+.snap {
+ width: 300px;
+ height: 300px;
+ background-color: green;
+ scroll-snap-align: start;
+}
+
+.area {
+ width: 2000px;
+ height: 2000px;
+}
+</style>
+
+<div id="scroller">
+ <div class="area"></div>
+ <div class="snap" style="top: 0px;"></div>
+ <div class="snap" style="top: 500px;"></div>
+</div>
+
+<script>
+test(() => {
+ // The initial snap position is at (0, 0).
+ assert_equals(scroller.scrollTop, 0);
+ assert_equals(scroller.scrollLeft, 0);
+
+ // Scroll to a position where it's outside of the scroll-snap proximity
+ // threshold, so that it won't trigger snapping.
+ scroller.scrollTo(0, 250);
+
+ assert_equals(scroller.scrollTop, 250);
+ assert_equals(scroller.scrollLeft, 0);
+
+ // Changing the initial snap target position, but still it's outside of the
+ // threshold.
+ document.querySelectorAll(".snap")[0].style.top = "10px";
+
+ // Not re-snap to the last snap point.
+ assert_equals(scroller.scrollTop, 250);
+ assert_equals(scroller.scrollLeft, 0);
+}, "Not re-snap once after a scroll operation has finished without snapping " +
+ "because the scroll destination was outside of the snap proximity threshold.");
+</script>
diff --git a/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/remove-current-target.html b/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/remove-current-target.html
new file mode 100644
index 0000000000..82bddf8074
--- /dev/null
+++ b/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/remove-current-target.html
@@ -0,0 +1,65 @@
+<!DOCTYPE html>
+<title>
+ Removing the current snap target should make the scroller snap to a new target.
+</title>
+<link rel="help" href="https://drafts.csswg.org/css-scroll-snap/#re-snap" />
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<style>
+div {
+ position: absolute;
+ margin: 0;
+}
+
+#scroller {
+ height: 500px;
+ width: 500px;
+ overflow: hidden;
+ scroll-snap-type: both mandatory;
+}
+
+#initial-target {
+ width: 300px;
+ height: 300px;
+ top: 100px;
+ left: 100px;
+ background-color: red;
+ scroll-snap-align: start;
+}
+
+#other-target {
+ width: 300px;
+ height: 300px;
+ top: 300px;
+ left: 300px;
+ background-color: green;
+ scroll-snap-align: start;
+}
+
+.area {
+ width: 2000px;
+ height: 2000px;
+}
+</style>
+
+<div id="scroller">
+ <div class="area"></div>
+ <div id="initial-target"></div>
+ <div id="other-target"></div>
+</div>
+
+<script>
+const initial_target = document.getElementById("initial-target");
+const other_target = document.getElementById("other-target");
+const scroller = document.getElementById("scroller");
+
+test(() => {
+ scroller.scrollTo(0,0);
+ assert_equals(scroller.scrollTop, 100);
+ assert_equals(scroller.scrollLeft, 100);
+
+ scroller.removeChild(initial_target);
+ assert_equals(scroller.scrollTop, 300);
+ assert_equals(scroller.scrollLeft, 300);
+}, "Removing the current snap target should make the scroller snap to a new target.");
+</script>
diff --git a/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/resnap-to-focused.html b/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/resnap-to-focused.html
new file mode 100644
index 0000000000..637c578a85
--- /dev/null
+++ b/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/resnap-to-focused.html
@@ -0,0 +1,82 @@
+<!doctype html>
+<title>Resnap to focused element after relayout</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<style>
+
+#snapper {
+ counter-reset: child 0;
+ width: 200px;
+ scroll-snap-type: block mandatory;
+ overflow:hidden;
+ height: 100px;
+}
+.child {
+ width: 100px;
+ height: 100px;
+ background:red;
+ text-align: center;
+ box-sizing: border-box;
+ counter-increment: child;
+ float: left;
+}
+.child.f {
+ background: green;
+ scroll-snap-align: center;
+}
+.child::before {
+ content: counter(child);
+}
+
+</style>
+
+<link rel=author title="Tab Atkins-Bittner" href="https://www.xanthir.com/contact/">
+<link rel="help" href="https://drafts.csswg.org/css-scroll-snap/#re-snap">
+<!--
+When re-snapping after a layout change,
+if multiple elements were capable of being the snap target previously,
+and one of them is focused,
+you must resnap to the focused one.
+-->
+<div id=snapper>
+ <div class="child no-snap" tabindex=-1></div>
+ <div class=child></div>
+ <div class="child f" tabindex=-1></div>
+ <div class="child f" tabindex=-1></div>
+ <div class=child></div>
+ <div class=child></div>
+</div>
+
+<script>
+
+var container = document.querySelector("#snapper");
+var [one,two] = document.querySelectorAll(".child.f");
+var unsnappable = document.querySelector(".child.no-snap");
+
+async_test(t=>{
+ requestAnimationFrame(()=>{
+ testSnap(t, one, 3);
+ requestAnimationFrame(()=>{
+ testSnap(t, two, 4);
+ requestAnimationFrame(()=>{
+ testSnap(t, one, 3);
+ t.done();
+ });
+ });
+ });
+});
+
+function testSnap(t, child, expectedRow) {
+ t.step(()=>{
+ unsnappable.focus();
+ container.style.width = "200px";
+ var startingRow = container.scrollTop/100 + 1;
+ assert_equals(startingRow, 2, "Initially snapped to row 2");
+ child.focus();
+ container.style.width = "100px";
+ var endingRow = container.scrollTop/100 + 1;
+ assert_equals(endingRow, expectedRow, `After resize, should snap to row ${expectedRow}.`);
+ });
+}
+
+</script>
diff --git a/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/snap-to-different-targets.html b/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/snap-to-different-targets.html
new file mode 100644
index 0000000000..7ad659d8a6
--- /dev/null
+++ b/testing/web-platform/tests/css/css-scroll-snap/snap-after-relayout/snap-to-different-targets.html
@@ -0,0 +1,92 @@
+<!DOCTYPE html>
+<title>
+ The scroller should try to resnap to targets for both axes if possible.
+</title>
+<link rel="help" href="https://drafts.csswg.org/css-scroll-snap/#re-snap" />
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<style>
+div {
+ position: absolute;
+ margin: 0;
+}
+
+#scroller {
+ height: 500px;
+ width: 500px;
+ overflow: hidden;
+ scroll-snap-type: both mandatory;
+}
+
+#x-axis-target {
+ scroll-snap-align: none start;
+ background-color: blue;
+ width: 100px;
+ height: 100px;
+ top: 400px;
+ left: 200px;
+}
+
+#y-axis-target {
+ scroll-snap-align: start none;
+ background-color: green;
+ width: 100px;
+ height: 100px;
+ top: 200px;
+ left: 400px;
+}
+
+#far-x-axis-target {
+ scroll-snap-align: none start;
+ background-color: blue;
+ width: 100px;
+ height: 100px;
+ top: 1200px;
+ left: 300px;
+}
+
+#far-y-axis-target {
+ scroll-snap-align: start none;
+ background-color: green;
+ width: 100px;
+ height: 100px;
+ top: 300px;
+ left: 1200px;
+}
+
+.area {
+ width: 2000px;
+ height: 2000px;
+}
+</style>
+
+<div id="scroller">
+ <div class="area"></div>
+ <div id="x-axis-target"></div>
+ <div id="y-axis-target"></div>
+ <div id="far-x-axis-target"></div>
+ <div id="far-y-axis-target"></div>
+</div>
+
+<script>
+
+const x_target = document.getElementById("x-axis-target");
+const y_target = document.getElementById("y-axis-target");
+const scroller = document.getElementById("scroller");
+
+test(t => {
+ // The scroller should be snapped to the two closest points on first layout.
+ assert_equals(scroller.scrollTop, 200);
+ assert_equals(scroller.scrollLeft, 200);
+ x_target.style.setProperty("left", "1000px");
+ y_target.style.setProperty("top", "1000px");
+
+ // The style change makes it impossible for the scroller to snap to both
+ // targets, but at least one of the targets should be preserved. The scroller
+ // should then re-evaluate the snap point for the other axis.
+ const snapped_to_x = scroller.scrollLeft == 1000 && scroller.scrollTop == 300;
+ const snapped_to_y = scroller.scrollTop == 1000 && scroller.scrollLeft == 300;
+ assert_true(snapped_to_x || snapped_to_y);
+}, "Scroller should snap to at least one of the targets if unable to snap to\
+both after a layout change.");
+</script>