<!doctype html>
<!--
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     http://creativecommons.org/publicdomain/zero/1.0/
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<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>