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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-21 11:44:51 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-21 11:44:51 +0000
commit9e3c08db40b8916968b9f30096c7be3f00ce9647 (patch)
treea68f146d7fa01f0134297619fbe7e33db084e0aa /layout/style/test/test_bug1490890.html
parentInitial commit. (diff)
downloadthunderbird-9e3c08db40b8916968b9f30096c7be3f00ce9647.tar.xz
thunderbird-9e3c08db40b8916968b9f30096c7be3f00ce9647.zip
Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1490890
+-->
+<head>
+ <meta charset="utf-8">
+ <title>Test for Bug 1490890</title>
+ <script src="/tests/SimpleTest/SimpleTest.js"></script>
+ <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+ <style>
+ #flex {
+ display: flex;
+ flex-direction: column;
+ height: 100px;
+ max-height: 100px;
+ overflow: hidden;
+ border: 1px solid black;
+ }
+ #overflowAuto {
+ overflow: auto;
+ white-space: pre-wrap;
+ }
+ </style>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1490890">Mozilla Bug 1490890</a>
+<div id="display">
+ <div id="content">
+ <div id="flex">
+ <div id="overflowAuto">
+ <!-- Populated by test JS below: -->
+ <div id="tall"></div>
+ </div>
+ <div id="testNode">abc</div>
+ </div>
+ </div>
+</div>
+<pre id="test">
+<script type="application/javascript">
+"use strict";
+
+/** Test for Bug 1490890 **/
+
+/**
+ * This test checks how many reflows are required, when we make a change inside
+ * a flex item, with a tall scrollable sibling flex item.
+ */
+
+const gUtils = SpecialPowers.getDOMWindowUtils(window);
+
+// The elements that we will modify here:
+const gTall = document.getElementById("tall");
+const gTestNode = document.getElementById("testNode");
+
+// Helper function to undo our modifications:
+function cleanup()
+{
+ gTall.firstChild.remove();
+ gTestNode.style = "";
+}
+
+// Flush layout & return the global frame-reflow-count
+function getReflowCount()
+{
+ let unusedVal = document.getElementById("flex").offsetHeight; // flush layout
+ return gUtils.framesReflowed;
+}
+
+// This function changes gTestNode to "display:none", and returns the number
+// of frames that need to be reflowed as a result of that tweak.
+function makeTweakAndCountReflows()
+{
+ let beforeCount = getReflowCount();
+ gTestNode.style.display = "none";
+ let afterCount = getReflowCount();
+
+ let numReflows = afterCount - beforeCount;
+ if (numReflows <= 0) {
+ ok(false, "something's wrong -- we should've reflowed *something*");
+ }
+ return numReflows;
+}
+
+// ACTUAL TEST LOGIC STARTS HERE
+// -----------------------------
+const testLineCount = 100;
+const refLineCount = 5000;
+
+// "Reference" measurement: put enough lines of text into gTall to trigger
+// a vertical scrollbar, and then see how many frames need to be reflowed
+// in response to a tweak in gTestNode:
+let text = document.createTextNode("a\n".repeat(testLineCount));
+gTall.appendChild(text);
+let numReferenceReflows = makeTweakAndCountReflows();
+cleanup();
+
+// "Test" measurement: put many more lines of text into gTall (many more than
+// for reference case), and then see how many frames need to be reflowed
+// in response to a tweak in gTestNode:
+text = document.createTextNode("a\n".repeat(refLineCount));
+gTall.appendChild(text);
+let numTestReflows = makeTweakAndCountReflows();
+cleanup();
+
+is(numTestReflows, numReferenceReflows,
+ "Tweak should trigger the same number of reflows regardless of " +
+ "how much content is present in descendant of sibling");
+</script>
+</pre>
+</body>
+</html>