margin-collapse-through-for-various-height-values.tentative.html

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This test has a WPT meta file that expects 19 subtest issues.
This WPT test may be referenced by the following Test IDs:
- /css/CSS2/normal-flow/margin-collapse-through-for-various-height-values.tentative.html - WPT Dashboard Interop Dashboard

<!DOCTYPE html>

<meta charset="utf-8">

<link rel="author" title="Oriol Brufau" href="obrufau@igalia.com">

<link rel="help" href="https://www.w3.org/TR/CSS22/box.html#collapsing-margins">

<link rel="help" href="https://github.com/w3c/csswg-drafts/issues/8919">

<link rel="help" href="https://github.com/servo/servo/pull/32064">

<meta name="assert" content="

  Margins can collapse through when the used height is zero, regardless of the computed values

  of `height`, `min-height` and `max-height`.

  Note that this test uses sizing values which didn't exist in CSS2, but since the expectations

  only depend on the used height, the test can still pass on implementations that don't support

  these values.

">

<style>

.before, .after {

  overflow: hidden;

.wrapper {

  border: 1px solid;

  margin-bottom: 2em;

.test {

  margin: 50px;

</style>

<div id="log"></div>

<script src="/resources/testharness.js"></script>

<script src="/resources/testharnessreport.js"></script>

<script>

let testcases = [

  // Tests for `height`

  { height: "auto" },

  { height: "0px" },

  { height: "1px" },

  { height: "0%", parentHeight: "auto" },

  { height: "0%", parentHeight: "0px" },

  { height: "0%", parentHeight: "100px" },

  { height: "1%", parentHeight: "auto" },

  { height: "1%", parentHeight: "0px" },

  { height: "1%", parentHeight: "100px" },

  { height: "calc(0px + 0%)", parentHeight: "auto" },

  { height: "calc(0px + 0%)", parentHeight: "0px" },

  { height: "calc(0px + 0%)", parentHeight: "100px" },

  { height: "calc(0px + 1%)", parentHeight: "auto" },

  { height: "calc(0px + 1%)", parentHeight: "0px" },

  { height: "calc(0px + 1%)", parentHeight: "100px" },

  { height: "calc(1px + 0%)", parentHeight: "auto" },

  { height: "calc(1px + 0%)", parentHeight: "0px" },

  { height: "calc(1px + 0%)", parentHeight: "100px" },

  { height: "calc(1px + 1%)", parentHeight: "auto" },

  { height: "calc(1px + 1%)", parentHeight: "0px" },

  { height: "calc(1px + 1%)", parentHeight: "100px" },

  { height: "stretch", parentHeight: "auto" },

  { height: "stretch", parentHeight: "0px" },

  { height: "stretch", parentHeight: "100px" },

  // Tests for `min-height` (with `height: auto`)

  { minHeight: "auto" },

  { minHeight: "0px" },

  { minHeight: "1px" },

  { minHeight: "0%", parentHeight: "auto" },

  { minHeight: "0%", parentHeight: "0px" },

  { minHeight: "0%", parentHeight: "100px" },

  { minHeight: "1%", parentHeight: "auto" },

  { minHeight: "1%", parentHeight: "0px" },

  { minHeight: "1%", parentHeight: "100px" },

  { minHeight: "calc(0px + 0%)", parentHeight: "auto" },

  { minHeight: "calc(0px + 0%)", parentHeight: "0px" },

  { minHeight: "calc(0px + 0%)", parentHeight: "100px" },

  { minHeight: "calc(0px + 1%)", parentHeight: "auto" },

  { minHeight: "calc(0px + 1%)", parentHeight: "0px" },

  { minHeight: "calc(0px + 1%)", parentHeight: "100px" },

  { minHeight: "calc(1px + 0%)", parentHeight: "auto" },

  { minHeight: "calc(1px + 0%)", parentHeight: "0px" },

  { minHeight: "calc(1px + 0%)", parentHeight: "100px" },

  { minHeight: "calc(1px + 1%)", parentHeight: "auto" },

  { minHeight: "calc(1px + 1%)", parentHeight: "0px" },

  { minHeight: "calc(1px + 1%)", parentHeight: "100px" },

  { minHeight: "stretch", parentHeight: "auto" },

  { minHeight: "stretch", parentHeight: "0px" },

  { minHeight: "stretch", parentHeight: "100px" },

  // Tests for `max-height` (with `height: 1px`)

  { height: "1px", maxHeight: "none" },

  { height: "1px", maxHeight: "0px" },

  { height: "1px", maxHeight: "1px" },

  { height: "1px", maxHeight: "0%", parentHeight: "auto" },

  { height: "1px", maxHeight: "0%", parentHeight: "0px" },

  { height: "1px", maxHeight: "0%", parentHeight: "100px" },

  { height: "1px", maxHeight: "1%", parentHeight: "auto" },

  { height: "1px", maxHeight: "1%", parentHeight: "0px" },

  { height: "1px", maxHeight: "1%", parentHeight: "100px" },

  { height: "1px", maxHeight: "calc(0px + 0%)", parentHeight: "auto" },

  { height: "1px", maxHeight: "calc(0px + 0%)", parentHeight: "0px" },

  { height: "1px", maxHeight: "calc(0px + 0%)", parentHeight: "100px" },

  { height: "1px", maxHeight: "calc(0px + 1%)", parentHeight: "auto" },

  { height: "1px", maxHeight: "calc(0px + 1%)", parentHeight: "0px" },

  { height: "1px", maxHeight: "calc(0px + 1%)", parentHeight: "100px" },

  { height: "1px", maxHeight: "calc(1px + 0%)", parentHeight: "auto" },

  { height: "1px", maxHeight: "calc(1px + 0%)", parentHeight: "0px" },

  { height: "1px", maxHeight: "calc(1px + 0%)", parentHeight: "100px" },

  { height: "1px", maxHeight: "calc(1px + 1%)", parentHeight: "auto" },

  { height: "1px", maxHeight: "calc(1px + 1%)", parentHeight: "0px" },

  { height: "1px", maxHeight: "calc(1px + 1%)", parentHeight: "100px" },

  { height: "1px", maxHeight: "stretch", parentHeight: "auto" },

  { height: "1px", maxHeight: "stretch", parentHeight: "0px" },

  { height: "1px", maxHeight: "stretch", parentHeight: "100px" },

];

function generate(testcase, serialization) {

  let { height, minHeight, maxHeight, parentHeight, ...unrecognized } = testcase;

  assert_array_equals(Object.keys(unrecognized), [], "No unrecognized key.");

  let wrapper = document.createElement("div");

  wrapper.className = "wrapper";

  wrapper.style.height = parentHeight || "";

  let before = document.createElement("div");

  before.className = "before";

  before.textContent = serialization;

  let after = document.createElement("div");

  after.className = "after";

  let test = document.createElement("div");

  test.className = "test";

  test.style.height = height || "";

  test.style.minHeight = minHeight || "";

  test.style.maxHeight = maxHeight || "";

  wrapper.append(before, test, after);

  document.body.append(wrapper);

  return [before, test, after];

function round(value) {

  return Math.round(value * 10) / 10;

let resolveDomReady;

let domReady = new Promise(resolve => {

  resolveDomReady = resolve;

});

for (let testcase of testcases) {

  let serialization = JSON.stringify(testcase);

  promise_test(async () => {

    let [before, test, after] = generate(testcase, serialization);

    // The checks below force layout, so as an optimization, run them asynchronously after generating all tests.

    await domReady;

    let height = round(test.getBoundingClientRect().height);

    let marginSum = round(after.getBoundingClientRect().top - before.getBoundingClientRect().bottom) - height;

    if (height === 0) {

      assert_equals(marginSum, 50, "margins should collapse through");

    } else {

      assert_equals(marginSum, 100, "margins should NOT collapse through when height is " + height);

  }, serialization);

resolveDomReady();

</script>