<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Elements not participating to the layout of their parent</title>
<link rel="help" href="https://w3c.github.io/mathml-core/#layout-algorithms">
<meta name="assert" content="Verify that display: none and out-of-flow positioned elements do not participate to layout of their parent.">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/mathml/support/feature-detection.js"></script>
<script src="/mathml/support/layout-comparison.js"></script>
<script src="/mathml/support/mathml-fragments.js"></script>
<script>
  var epsilon = 1;

  setup({ explicit_done: true });
  window.addEventListener("load", runTests);

  function runTests() {

    for (tag in MathMLFragments) {
        if (!FragmentHelper.isValidChildOfMrow(tag) ||
            FragmentHelper.isEmpty(tag))
            continue;
        ["display: none",
         "display: contents",
         "position: absolute",
         "position: fixed"
        ].forEach(style => {
            document.body.insertAdjacentHTML("beforeend", `<div style="position: absolute;">\
<div style="display: inline-block"><math>${MathMLFragments[tag]}</math></div>\
<div style="display: inline-block"><math>${MathMLFragments[tag]}</math></div>\
</div>`);
            var div = document.body.lastElementChild;

            var elementContainer = div.firstElementChild;
            var elementContainerWidth = elementContainer.getBoundingClientRect().width;
            var element = FragmentHelper.element(elementContainer);
            if (style === "display: contents" &&
                !element.classList.contains("mathml-container")) {
                // A "display: contents" MathML child is not participating to
                // parent layout because its computed style is "display: none".
                // If we cannot append a MathML child then skip that test.
                return;
            }
            FragmentHelper.forceNonEmptyElement(element);
            var allowInvalid = true;
            var child = FragmentHelper.appendChild(element, allowInvalid);
            child.setAttribute("style", style);

            var referenceContainer = div.lastElementChild;
            var referenceContainerWidth = referenceContainer.getBoundingClientRect().width;
            var reference = FragmentHelper.element(referenceContainer);
            FragmentHelper.forceNonEmptyElement(reference);

            test(function() {
                assert_true(MathMLFeatureDetection[`has_${tag}`](), `${tag} is supported`);
                assert_approx_equals(elementContainerWidth, referenceContainerWidth, epsilon);
            }, `${tag} preferred width calculation is not affected by children with "${style}" style`);

            test(function() {
                assert_true(MathMLFeatureDetection[`has_${tag}`](), `${tag} is supported`);
                compareLayout(element, reference, epsilon);
            }, `${tag} layout is not affected by children with "${style}" style`);

            div.style = "display: none;"; // Hide the div after measurement.
        });
    }

    done();
  }
</script>
</head>
<body>
  <div id="log"></div>
</body>
</html>
