Part 3 - Exclude flex item's margin-box at sticky position in flex container's scrollable overflow area.
Differential Revision: https://phabricator.services.mozilla.com/D208173
bugzilla-url: https://bugzilla.mozilla.org/show_bug.cgi?id=1748891
gecko-commit: 1f2bdb707f167eed5d98d8da88f511e00ab4c55d
gecko-reviewers: emilio
diff --git a/css/css-position/sticky/position-sticky-left-006.html b/css/css-position/sticky/position-sticky-left-006.html
new file mode 100644
index 0000000..63fa1eb
--- /dev/null
+++ b/css/css-position/sticky/position-sticky-left-006.html
@@ -0,0 +1,38 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Position Test: Test position:sticky element with 100% left in a flex container</title>
+<link rel="author" title="Ting-Yu Lin" href="mailto:tlin@mozilla.com">
+<link rel="author" title="Mozilla" href="https://www.mozilla.org/">
+<link rel="help" href="https://drafts.csswg.org/css-position/#sticky-pos">
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1748891">
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1835705">
+<link rel="match" href="../../reference/ref-filled-green-100px-square.xht">
+<meta name="assert" content="This test verifies that a position:sticky element with 100% left value does not cause the scrollbar to show when shrinking the width of its overflow container.">
+
+<style>
+#scroll {
+ display: flex;
+ width: 200px;
+ height: 100px;
+ overflow: auto;
+ background: red;
+}
+.sticky {
+ position: sticky;
+ width: 100px;
+ height: 100px;
+ left: 100%;
+ background: green;
+}
+</style>
+
+<p>Test passes if there is a filled green square and <strong>no red</strong>.</p>
+<div id="scroll">
+ <div class="sticky"></div>
+</div>
+
+<script>
+window.onload = () => {
+ document.getElementById("scroll").style.width = "100px";
+};
+</script>
diff --git a/css/css-position/sticky/position-sticky-top-006.html b/css/css-position/sticky/position-sticky-top-006.html
new file mode 100644
index 0000000..4ac5310
--- /dev/null
+++ b/css/css-position/sticky/position-sticky-top-006.html
@@ -0,0 +1,38 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Position Test: Test position:sticky element with 100% top in a flex container</title>
+<link rel="author" title="Ting-Yu Lin" href="mailto:tlin@mozilla.com">
+<link rel="author" title="Mozilla" href="https://www.mozilla.org/">
+<link rel="help" href="https://drafts.csswg.org/css-position/#sticky-pos">
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1748891">
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1835705">
+<link rel="match" href="../../reference/ref-filled-green-100px-square.xht">
+<meta name="assert" content="This test verifies that a position:sticky element with 100% top value does not cause the scrollbar to show when shrinking the height of its container.">
+
+<style>
+#scroll {
+ display: flex;
+ width: 100px;
+ height: 200px;
+ overflow: auto;
+ background: red;
+}
+.sticky {
+ position: sticky;
+ width: 100px;
+ height: 100px;
+ top: 100%;
+ background: green;
+}
+</style>
+
+<p>Test passes if there is a filled green square and <strong>no red</strong>.</p>
+<div id="scroll">
+ <div class="sticky"></div>
+</div>
+
+<script>
+window.onload = () => {
+ document.getElementById("scroll").style.height = "100px";
+};
+</script>
