Test for calc() rounding error.
bugzilla-url: https://bugzilla.mozilla.org/show_bug.cgi?id=1323735
gecko-commit: fdac7a88a2c099144e6587f45e07c838b9136c92
gecko-integration-branch: autoland
gecko-reviewers: mats
diff --git a/css/css-values/calc-rounding-001.html b/css/css-values/calc-rounding-001.html
new file mode 100644
index 0000000..dfd03a6
--- /dev/null
+++ b/css/css-values/calc-rounding-001.html
@@ -0,0 +1,43 @@
+<!doctype html>
+<!--
+ Any copyright is dedicated to the Public Domain.
+ http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<meta charset="utf-8">
+<title>CSS Test: calc rounding doesn't accumulate a lot of error.</title>
+<link rel="author" href="mailto:mats@mozilla.com" title="Mats Palmgren">
+<link rel="author" href="mailto:emilio@crisal.io" title="Emilio Cobos Álvarez">
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1323735">
+<link rel="help" href="https://drafts.csswg.org/css-values/#funcdef-calc">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<style>
+body {
+ background: #f3f5f6;
+}
+
+div {
+ font-size: 15px;
+ width: 401px;
+ margin: 20px;
+ background: #fff;
+ display: flex;
+ flex-wrap: wrap;
+}
+
+b {
+ height: 50px;
+ background: red;
+ width: calc((100% - 4.5em) / 4); /* .5em gutters */
+}
+
+b:not(:last-child) {
+ margin-right: 1.5em;
+}
+</style>
+<div><b></b><b></b><b></b><b></b></div>
+<script>
+ test(function() {
+ assert_equals(document.querySelector("div").offsetHeight, 50);
+ }, "calc() doesn't accumulate much error that makes flex items overflow");
+</script>
