Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
author: Daniel Baumann <daniel.baumann@progress-linux.org> 2024-04-19 00:47:55 +0000
committer: Daniel Baumann <daniel.baumann@progress-linux.org> 2024-04-19 00:47:55 +0000
commit: 26a029d407be480d791972afb5975cf62c9360a6 (patch)
tree: f435a8308119effd964b339f76abb83a57c29483 /testing/web-platform/tests/css/css-display
parent: Initial commit. (diff)
download: firefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz
firefox-26a029d407be480d791972afb5975cf62c9360a6.zip
384 files changed, 11571 insertions, 0 deletions
diff --git a/testing/web-platform/tests/css/css-display/META.yml b/testing/web-platform/tests/css/css-display/META.yml
new file mode 100644
index 0000000000..4e70cb4630
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/META.yml
@@ -0,0 +1,5 @@
+spec: https://drafts.csswg.org/css-display/
+suggested_reviewers:
+  - kojiishi
+  - tabatkins
+  - fantasai
diff --git a/testing/web-platform/tests/css/css-display/accessibility/display-contents-role-and-label.html b/testing/web-platform/tests/css/css-display/accessibility/display-contents-role-and-label.html
new file mode 100644
index 0000000000..4a06d0ff5b
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/accessibility/display-contents-role-and-label.html
@@ -0,0 +1,302 @@
+<!doctype html>
+<html>
+<head>
+  <title>Testing accessibility of display: contents</title>
+  <link rel="help" href="https://drafts.csswg.org/css-display-4/#box-generation">
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/resources/testdriver.js"></script>
+  <script src="/resources/testdriver-vendor.js"></script>
+  <script src="/resources/testdriver-actions.js"></script>
+  <script src="/wai-aria/scripts/aria-utils.js"></script>
+</head>
+<body>
+
+  <!-- Dec 2023 notes for "display: contents" testing:
+  - Per CSS spec, setting "display: contents" must not alter an element's semantics (https://www.w3.org/TR/css-display-3/#valdef-display-contents):
+  "As only the box tree is affected, any semantics based on the document tree, such as selector-matching, event handling, and
+  property inheritance, are not affected."
+
+   - As of December 2023, the current state of cross-browser, automated web accessibility testing is limited to retrieving the following
+  accessibility object properties with planned future enhancements (https://github.com/WICG/aom/issues/203):
+      - computedRole
+      - computedLabel
+  -->
+
+  <h1>Testing accessibility of display: contents</h1>
+
+  <p>Verifies accessibility behavior of the <a href="https://www.w3.org/TR/css-display-3/#box-generation">contents</a> keyword for the CSS display property</p>
+
+  <h2>Accname</h2>
+
+  <button aria-labelledby="b2" style="display: contents;" data-expectedlabel="hidden label" data-expectedrole="button" data-testname="button with display: contents is labelled via referenced hidden span" class="ex-role-and-label">
+      <span aria-hidden="true" id="b2">hidden label</span>
+      <span hidden>hidden from all users</span>
+      <span>visible to all users</span>
+  </button>
+
+  <span id="a1">label</span>
+  <a href="#" aria-labelledby="a1" style="display: contents;" data-expectedlabel="label" data-expectedrole="link" data-testname="link with display: contents is labelled via aria-labelledby" class="ex-role-and-label">x</a>
+  <nav aria-labelledby="a1" style="display: contents;" data-expectedlabel="label" data-expectedrole="navigation" data-testname="nav with display: contents is labelled via aria-labelledby" class="ex-role-and-label">x</nav>
+
+  <button aria-label="label" style="display: contents;" data-expectedlabel="label" data-expectedrole="button" data-testname="button with display: contents is labelled via aria-label" class="ex-role-and-label">x</button>
+  <div role="group" aria-label="label" style="display: contents;" data-expectedlabel="label" data-expectedrole="group" data-testname="div with role group with display: contents is labelled via aria-label" class="ex-role-and-label">x</div>
+
+  <!-- <img> renders "display: contents" the same as "display:none", see: https://www.w3.org/TR/css-display-3/#unbox-html-->
+  <label for="label-for-button">label</label>
+  <button id="label-for-button" style="display: contents;" data-expectedlabel="label" data-expectedrole="button" data-testname="button with display: contents is labelled via label for/id association" class="ex-role-and-label">x</button>
+  <!-- SVG and display: contents behavior: https://github.com/w3c/svgwg/issues/305-->
+  <svg viewbox="0 0 100 50">
+    <g style="display: contents;" fill="silver" stroke="blue" data-expectedlabel="group label" data-expectedrole="group" data-testname="g element with display: contents, as child of svg, is labelled via title element" class="ex-role-and-label">
+      <title>group label</title>
+      <circle cx="20" cy="20" r="10" />
+      <circle cx="20" cy="20" r="10" />
+    </g>
+  </svg>
+
+  <a href="#" style="display: contents;" data-expectedlabel="label" data-expectedrole="link" data-testname="link with display: contents is labelled via name from contents" class="ex-role-and-label">label</a>
+  <button style="display: contents;" data-expectedlabel="label" data-expectedrole="button" data-testname="button with display: contents is labelled via name from contents" class="ex-role-and-label">label</button>
+  <h3 style="display: contents;" data-expectedlabel="label" data-expectedrole="heading" data-testname="h3 with display: contents is labelled via name from contents" class="ex-role-and-label">label</h3>
+
+  <h2>Accessibility roles</h2>
+  <!-- Buttons -->
+  <button style="display: contents;" data-expectedrole="button" data-expectedlabel="x" data-testname="button with display: contents has button role" class="ex-role-and-label">x</button>
+  <button role="button" style="display: contents;" data-expectedrole="button" data-expectedlabel="x" data-testname="button with explicit button role and display: contents has button role" class="ex-role-and-label">x</button>
+  <div role="button" style="display: contents;" data-expectedrole="button" data-expectedlabel="x" data-testname="div with button role and display: contents has button role" class="ex-role-and-label">x</div>
+  <div role="button" tabindex="0" style="display: contents;" data-expectedrole="button" data-expectedlabel="x" data-testname="div with button role, tabindex=0 and display: contents has button role" class="ex-role-and-label">x</div>
+
+  <!-- Display: Flex -->
+  <table style="display: flex; flex-flow: column nowrap;" data-expectedrole="table">
+    <thead>
+      <tr style="display: contents;" data-expectedrole="row" data-testname="tr with display: contents, within table with display: flex, has row role" class="ex-role">
+        <th data-expectedrole="columnheader" data-expectedlabel="x" data-testname="th as child of tr with display: contents, within table with display: flex, has columnheader role" class="ex-role-and-label">x</th>
+        <th>x</th>
+      </tr>
+    </thead>
+    <tbody>
+      <tr style="display: contents;">
+        <td data-expectedrole="cell" data-expectedlabel="x" data-testname="td as child of tr with display: contents, within table with display: flex, has cell role" class="ex-role-and-label">x</td>
+        <td>x</td>
+      </tr>
+    </tbody>
+  </table>
+
+  <table role="table" style="display: flex; flex-flow: column nowrap;" data-expectedrole="table">
+    <thead>
+      <tr style="display: contents;" data-expectedrole="row" data-testname="tr with display: contents, within table with role=table with display: flex, has row role" class="ex-role">
+        <th data-expectedrole="columnheader" data-expectedlabel="x" data-testname="th as child of tr with display: contents, within table with role=table with display: flex, has columnheader role" class="ex-role-and-label">x</th>
+        <th>x</th>
+      </tr>
+    </thead>
+    <tbody>
+      <tr style="display: contents;">
+        <td data-expectedrole="cell" data-expectedlabel="x" data-testname="td as child of tr with display: contents, within table with role=table with display: flex, has cell role" class="ex-role-and-label">x</td>
+        <td>x</td>
+      </tr>
+    </tbody>
+  </table>
+
+  <table role="grid" style="display: flex; flex-flow: column nowrap;" data-expectedrole="grid">
+    <thead>
+      <tr style="display: contents;" data-expectedrole="row" data-testname="tr with display: contents, within table with role=grid with display: flex, has row role" class="ex-role">
+        <th data-expectedrole="columnheader" data-expectedlabel="x" data-testname="th as child of tr with display: contents, within table with role=grid with display: flex, has columnheader role" class="ex-role-and-label">x</th>
+        <th>x</th>
+      </tr>
+    </thead>
+    <tbody>
+      <tr style="display: contents;">
+        <td data-expectedrole="gridcell" data-expectedlabel="x" data-testname="td (no explicit role) as child of tr with display: contents, within table with role=grid with display: flex, has gridcell role" class="ex-role-and-label">x</td>
+        <td>x</td>
+      </tr>
+    </tbody>
+  </table>
+
+  <!-- Display: Grid -->
+  <div style="display: grid; grid-template-columns: 1fr 100px; grid-gap: 1em;">
+    <h2>x</h2>
+    <ul style="display: contents" data-expectedrole="list" data-testname="ul with display: contents, as child of div with display: grid, has list role" class="ex-role">
+      <li>x</li>
+      <li data-expectedrole="listitem" data-expectedlabel="x" data-testname="listitem within ul with display: contents, as child of div with display: grid, has listitem role" class="ex-role-and-label">x</li>
+    </ul>
+  </div>
+
+  <!-- Generics -->
+  <div style="display: contents;" data-testname="div with display: contents has generic role" class="ex-generic">x</div>
+  <span style="display: contents;" data-testname="span with display: contents has generic role" class="ex-generic">x</span>
+
+  <!-- Headings -->
+  <h3 style="display: contents;" data-expectedrole="heading" data-expectedlabel="x" data-testname="h3 with display: contents has heading role" class="ex-role-and-label">x</h3>
+  <div role="heading" aria-level="3" style="display: contents;" data-expectedrole="heading" data-expectedlabel="x" data-testname="div with heading role, aria-level=3 and display: contents has heading role" class="ex-role-and-label">x</div>
+  <span role="heading" aria-level="1" style="display: contents;" data-expectedrole="heading" data-expectedlabel="x" data-testname="span with heading role, aria-level=1 and display: contents has heading role" class="ex-role-and-label">x</span>
+
+  <!-- Landmarks and regions -->
+  <header style="display: contents;" data-expectedrole="banner" data-testname="header with display: contents has banner role" class="ex-role">x</header>
+  <nav style="display: contents;" aria-label="label" data-expectedrole="navigation" data-testname="nav with display: contents and aria-label has navigation role" class="ex-role-and-label">x</nav>
+  <aside style="display: contents;" aria-label="label" data-expectedrole="complementary" data-testname="aside with display: contents and aria-label has complementary role" class="ex-role-and-label">x</aside>
+  <main style="display: contents;" data-expectedrole="main" data-testname="main with display: contents has main role" class="ex-role">x</main>
+  <footer style="display: contents;" data-expectedrole="contentinfo" data-testname="footer with display: contents has contentinfo role" class="ex-role">x</footer>
+  <form aria-label="label" style="display: contents;" data-expectedrole="form" data-expectedlabel="label" data-testname="form with display: contents has form role" class="ex-role-and-label">x</form>
+  <search style="display: contents;" data-expectedrole="search" data-testname="search with display: contents has search role" class="ex-role">x</search>
+  <section aria-label="label" style="display: contents;" data-expectedrole="region" data-expectedlabel="label" data-testname="section with aria-label and display: contents has region role" class="ex-role-and-label"></section>
+
+  <div role="banner" style="display: contents;" data-expectedrole="banner" data-testname="div with role banner and display: contents has banner role" class="ex-role">x</div>
+  <div role="navigation" aria-label="label" style="display: contents;" data-expectedrole="navigation" data-testname="div with role navigation, aria-label and display: contents has navigation role" class="ex-role-and-label">x</div>
+  <div role="complementary" aria-label="label" style="display: contents;" data-expectedrole="complementary" data-testname="div with role complementary, aria-label and display: contents has complementary role" class="ex-role-and-label">x</div>
+  <div role="main" style="display: contents;" data-expectedrole="main" data-testname="div with role main and display: contents has main role" class="ex-role">x</div>
+  <div role="contentinfo" style="display: contents;" data-expectedrole="contentinfo" data-testname="div with role contentinfo and display: contents has contentinfo role" class="ex-role">x</div>
+  <div role="form" aria-label="label" style="display: contents;" data-expectedrole="form" data-expectedlabel="label" data-testname="div with role form, aria-label and display: contents has form role" class="ex-role-and-label">x</div>
+  <div role="search" aria-label="label" style="display: contents;" data-expectedrole="search" data-testname="div with role search and display: contents has search role" class="ex-role-and-label">x</div>
+  <div role="region" aria-label="label" style="display: contents;" data-expectedrole="region" data-expectedlabel="label" data-testname="div with role region, aria-label and display: contents has region role" class="ex-role-and-label">x</div>
+
+  <!-- Links -->
+  <a href="#" style="display: contents;" data-expectedrole="link" data-expectedlabel="x" data-testname="link with display: contents has link role" class="ex-role-and-label">x</a>
+  <a href="#" role="link" style="display: contents;" data-expectedrole="link" data-expectedlabel="x" data-testname="link with explicit link role and display: contents has link role" class="ex-role-and-label">x</a>
+  <div role="link" style="display: contents;" data-expectedrole="link" data-expectedlabel="x" data-testname="div with link role and display: contents has link role" class="ex-role-and-label">x</div>
+  <div role="link" tabindex="0" style="display: contents;" data-expectedrole="link" data-expectedlabel="x" data-testname="div with link role, tabindex=0 and display: contents has link role" class="ex-role-and-label">x</div>
+
+  <!-- Lists -->
+  <ul role="list" style="display: contents;" data-expectedrole="list" data-testname="ul with role list and display: contents (child li has display: contents) has list role" class="ex-role">
+    <li style="display: contents;" data-expectedrole="listitem" data-expectedlabel="x" data-testname="li as child of ul with role list, both with display: contents, has listitem role" class="ex-role-and-label">x</li>
+    <li>y</li>
+  </ul>
+
+  <ul role="list" style="display: contents;" data-expectedrole="list" data-testname="ul with role list and display: contents has list role" class="ex-role">
+    <li>x</li>
+    <li data-expectedrole="listitem" data-expectedlabel="y" data-testname="li, as child of ul with role list and display: contents, has listitem role" class="ex-role-and-label">y</li>
+  </ul>
+
+  <ul role="list">
+    <li>x</li>
+    <li style="display: contents;" data-expectedrole="listitem" data-expectedlabel="y" data-testname="li with display: contents, as child of ul with role list, has listitem role" class="ex-role-and-label">y</li>
+  </ul>
+
+  <ol role="list" style="display: contents;" data-expectedrole="list" data-testname="ol with role list and display: contents has list role (child li has display: contents)" class="ex-role">
+    <li style="display: contents;" data-expectedrole="listitem" data-expectedlabel="x" data-testname="li as child of ol with role list, both with display: contents, has listitem role" class="ex-role-and-label">x</li>
+    <li>y</li>
+  </ol>
+
+  <ol role="list" style="display: contents;" data-expectedrole="list" data-testname="ol with role list and display: contents has list role" class="ex-role">
+    <li>x</li>
+    <li data-expectedrole="listitem" data-expectedlabel="y" data-testname="li, as child of ol with role list and display: contents, has listitem role" class="ex-role-and-label">y</li>
+  </ol>
+
+  <ol role="list">
+    <li>x</li>
+    <li style="display: contents;" data-expectedrole="listitem" data-expectedlabel="y" data-testname="li with display: contents, as child of ol with role list, has listitem role" class="ex-role-and-label">y</li>
+  </ol>
+
+  <div role="list" style="display: contents;" data-expectedrole="list" data-testname="div with list role and display: contents has list role" class="ex-role">
+    <div role="listitem" data-expectedrole="listitem" data-expectedlabel="x" data-testname="div with listitem role, as child of div with display: contents, has listitem role" class="ex-role-and-label">x</div>
+    <div>y</div>
+  </div>
+
+  <div role="list" style="display: contents;" data-expectedrole="list" data-testname="div with list role and display: contents has list role (child div with listitem role has display: contents)" class="ex-role">
+    <div>x</div>
+    <div role="listitem" style="display: contents;" data-expectedrole="listitem" data-expectedlabel="y" data-testname="div with listitem role (as child of div with list role), both with display: contents, has listitem role" class="ex-role-and-label">y</div>
+  </div>
+
+  <div role="list">
+    <div>x</div>
+    <div role="listitem" style="display: contents;" data-expectedrole="listitem" data-expectedlabel="y" data-testname="div with listitem role with display: contents, as child of div with list role, has listitem role" class="ex-role-and-label">y</div>
+  </div>
+
+  <!-- Lists: description/definition lists -> wpt/html-aam/roles.html -->
+
+  <!-- Tables (including grids/treegrids) -->
+  <table role="table" style="display: contents;" data-expectedrole="table" data-testname="table with role table and display: contents has table role" class="ex-role">
+    <thead>
+      <tr style="display: contents;" data-expectedrole="row" data-testname="tr in table with role table and display: contents has row role" class="ex-role">
+        <th style="display: contents;" data-expectedrole="columnheader" data-expectedlabel="x" data-testname="td within tr both with display: contents, in table with role table and display: contents, has columnheader role" class="ex-role-and-label">x</th>
+        <th>x</th>
+      </tr>
+    </thead>
+    <tbody>
+      <tr>
+        <td style="display: contents;" data-expectedrole="cell" data-expectedlabel="x" data-testname="td within tr in table with role table, all with display: contents, has cell role" class="ex-role-and-label">x</td>
+        <td>x</td>
+      </tr>
+    </tbody>
+  </table>
+
+  <div role="table" style="display: contents;" data-expectedrole="table" data-testname="div with role table with display: contents has table role" class="ex-role">
+    <div role="rowgroup" style="display: contents;" data-expectedrole="rowgroup" data-testname="div with role rowgroup in div with role table, both with display: contents, has rowgroup role" class="ex-role">
+      <div role="row">
+        <div role="columnheader" style="display: contents;" data-expectedrole="columnheader" data-expectedlabel="x" data-testname="div with role columnheader with display: contents, in div with role rowgroup within div with table role both with display: contents, has columnheader role" class="ex-role-and-label">x</div>
+        <div role="columnheader">x</div>
+      </div>
+    </div>
+    <div role="rowgroup">
+      <div role="row">
+        <div role="cell">x</div>
+        <div role="cell">x</div>
+      </div>
+    </div>
+  </div>
+
+  <table role="grid" style="display: contents;" data-expectedrole="grid" data-testname="table with role grid and display: contents has grid role">
+    <thead>
+      <tr style="display: contents;" data-expectedrole="row" data-testname="tr within table with role grid, both with display: contents, has row role">
+        <th style="display: contents;" data-expectedrole="columnheader" data-expectedlabel="x" data-testname="th within table with role grid, both with display: contents, has columnheader role" class="ex-role-and-label">x</th>
+        <th>x</th>
+      </tr>
+    </thead>
+    <tbody>
+      <tr>
+        <td style="display: contents;" data-expectedrole="gridcell" data-expectedlabel="x" data-testname="td within table with role grid, both with display: contents, has gridcell role" class="ex-role-and-label">x</td>
+        <td>x</td>
+      </tr>
+    </tbody>
+  </table>
+
+  <div role="grid" style="display: contents;" data-expectedrole="grid" data-testname="div with role grid with display: contents has grid role" class="ex-role">
+    <div role="rowgroup" style="display: contents;" data-expectedrole="rowgroup" data-testname="div with role rowgroup in div with role grid, both with display: contents, has rowgroup role" class="ex-role">
+      <div role="row">
+        <div role="columnheader" style="display: contents;" data-expectedrole="columnheader" data-expectedlabel="x" data-testname="div with role columnheader with display: contents, in div with role rowgroup within div with grid role both with display: contents, has rowgroup role" class="ex-role-and-label">x</div>
+        <div role="columnheader">x</div>
+      </div>
+    </div>
+    <div role="rowgroup">
+      <div role="row">
+        <div role="gridcell"></div>
+        <div role="gridcell" style="display: contents;" data-expectedrole="gridcell" data-expectedlabel="x" data-testname="div with gridcell role and display: contents, within div with role row contained in a div with role grid both with display: contents, has gridcell role" class="ex-role-and-label">x</div>
+      </div>
+    </div>
+  </div>
+
+  <table role="grid" tabindex="0" style="display: contents;" data-expectedrole="grid" data-testname="div with role grid, tabindex=0 and display: contents has grid role" >
+    <thead>
+      <tr>
+        <th>x</th>
+        <th>x</th>
+      </tr>
+    </thead>
+    <tbody>
+      <tr>
+        <td>x</td>
+        <td>x</td>
+      </tr>
+    </tbody>
+  </table>
+
+  <table role="treegrid" style="display: contents;" data-expectedrole="treegrid" data-testname="table with role treegrid and display: contents has treegrid role" class="ex-role"></table>
+  <div role="treegrid" style="display: contents;" data-expectedrole="treegrid" data-testname="div with role treegrid and display: contents has treegrid role" class="ex-role"></div>
+
+  <ul role="tree" style="display: contents;" data-expectedrole="tree" data-testname="ul with role tree and display: contents has tree role" class="ex-role">
+    <li role="treeitem" aria-expanded="true" style="display: contents;" data-expectedrole="treeitem" data-expectedlabel="x" data-testname="li with role treeitem and display: contents, within ul with role tree and display: contents, has treeitem role" class="ex-role-and-label">
+      <span>x</span>
+      <ul role="group">
+        <li role="treeitem" aria-expanded="false" style="display: contents;" data-expectedrole="treeitem" data-expectedlabel="x" data-testname="li with role treeitem and display: contents, within ul with role=group (within ul with role tree and display: contents), has treeitem role" class="ex-role-and-label">
+          <span>x</span>
+        </li>
+      </ul>
+    </li>
+  </ul>
+
+<script>
+  AriaUtils.verifyRolesBySelector(".ex-role");
+  AriaUtils.verifyRolesAndLabelsBySelector(".ex-role-and-label");
+  AriaUtils.verifyGenericRolesBySelector(".ex-generic");
+</script>
+
+</body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/animations/display-interpolation.html b/testing/web-platform/tests/css/css-display/animations/display-interpolation.html
new file mode 100644
index 0000000000..6bf3dcc5a4
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/animations/display-interpolation.html
@@ -0,0 +1,20 @@
+<!DOCTYPE html>
+<meta charset="UTF-8">
+<title>display interpolation</title>
+<link rel="help" href="https://www.w3.org/TR/CSS2/visuren.html#display-prop">
+<meta name="assert" content="display supports animation">
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/css/support/interpolation-testcommon.js"></script>
+
+<body>
+<script>
+test_not_animatable({
+  property: 'display',
+  from: 'none',
+  to: 'flex',
+  underlying: 'block'
+});
+</script>
+</body>
diff --git a/testing/web-platform/tests/css/css-display/animations/display-interpolation.tentative.html b/testing/web-platform/tests/css/css-display/animations/display-interpolation.tentative.html
new file mode 100644
index 0000000000..b6b58ee45e
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/animations/display-interpolation.tentative.html
@@ -0,0 +1,21 @@
+<!DOCTYPE html>
+<meta charset="UTF-8">
+<title>display interpolation</title>
+<link rel="help" href="https://www.w3.org/TR/CSS2/visuren.html#display-prop">
+<meta name="assert" content="display supports animation">
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/css/support/interpolation-testcommon.js"></script>
+
+<body>
+  <script>
+    test_no_interpolation({
+      property: 'display',
+      from: 'grid',
+      to: 'flex',
+      underlying: 'block',
+      target_names: ['CSS Animations', 'Web Animations']
+    });
+  </script>
+</body>
diff --git a/testing/web-platform/tests/css/css-display/display-change-iframe.html b/testing/web-platform/tests/css/css-display/display-change-iframe.html
new file mode 100644
index 0000000000..5fc53274e2
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-change-iframe.html
@@ -0,0 +1,27 @@
+<!DOCTYPE html>
+<html class="reftest-wait">
+  <link rel="author" title="Morten Stenshorne" href="mailto:mstensho@chromium.org">
+  <link rel="help" href="https://www.w3.org/TR/css-display-3/#outer-role">
+  <link rel="help" href="https://html.spec.whatwg.org/multipage/rendering.html#replaced-elements">
+  <link rel="match" href="../reference/ref-filled-green-100px-square.xht">
+  <p>Test passes if there is a filled green square and <strong>no red</strong>.</p>
+  <iframe id="victim" src="support/red-square.html" style="width:100px; height:100px; border:none;"></iframe>
+  <script>
+    var loaded_once = false;
+    victim.onload = function() {
+        // The child document should only load once. It should not be reloaded
+        // by changing the display type of the IFRAME.
+        if (loaded_once)
+            return;
+        loaded_once = true;
+        var childDoc = victim.contentWindow.document;
+        // Change the red background to green. This will revert back to red if
+        // the document gets reloaded (which shouldn't happen) when re-attaching
+        // #victim.
+        childDoc.getElementById("square").style.background = "green";
+        document.offsetTop;
+        victim.style.display = "block";
+        document.documentElement.className = "";
+    }
+  </script>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/display-change-object-iframe.html b/testing/web-platform/tests/css/css-display/display-change-object-iframe.html
new file mode 100644
index 0000000000..a44cfde79e
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-change-object-iframe.html
@@ -0,0 +1,27 @@
+<!DOCTYPE html>
+<html class="reftest-wait">
+  <link rel="author" title="Morten Stenshorne" href="mailto:mstensho@chromium.org">
+  <link rel="help" href="https://www.w3.org/TR/css-display-3/#outer-role">
+  <link rel="help" href="https://html.spec.whatwg.org/multipage/rendering.html#replaced-elements">
+  <link rel="match" href="../reference/ref-filled-green-100px-square.xht">
+  <p>Test passes if there is a filled green square and <strong>no red</strong>.</p>
+  <object id="victim" data="support/red-square.html" style="width:100px; height:100px;"></object>
+  <script>
+    var loaded_once = false;
+    victim.onload = function() {
+        // The child document should only load once. It should not be reloaded
+        // by changing the display type of the OBJECT.
+        if (loaded_once)
+            return;
+        loaded_once = true;
+        var childDoc = victim.contentWindow.document;
+        // Change the red background to green. This will revert back to red if
+        // the document gets reloaded (which shouldn't happen) when re-attaching
+        // #victim.
+        childDoc.getElementById("square").style.background = "green";
+        document.offsetTop;
+        victim.style.display = "block";
+        document.documentElement.className = "";
+    }
+  </script>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-001-crash.html b/testing/web-platform/tests/css/css-display/display-contents-001-crash.html
new file mode 100644
index 0000000000..376c3b549a
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-001-crash.html
@@ -0,0 +1,13 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="UTF-8">
+<link rel="author" title="Daniel Holbert" href="mailto:dholbert@mozilla.com">
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1144434">
+</head>
+<body onload="c.style.display = 'inline-block';">
+
+<div style="display: table-cell;"></div><div style="display: contents;"><div id="c"></div></div>
+
+</body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-alignment-001-ref.html b/testing/web-platform/tests/css/css-display/display-contents-alignment-001-ref.html
new file mode 100644
index 0000000000..595aa7f7e5
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-alignment-001-ref.html
@@ -0,0 +1,23 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test Reference</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<style>
+  .container {
+    display: flex;
+    width: 300px;
+    height: 300px;
+    align-items: center;
+    border: 2px solid purple;
+  }
+  .container > div {
+    width: 100px;
+    height: 100px;
+    background: blue;
+    align-self: auto;
+  }
+</style>
+<p>Test passes if there's a blue square vertically centered inside the box.</p>
+<div class="container">
+  <div></div>
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-alignment-001.html b/testing/web-platform/tests/css/css-display/display-contents-alignment-001.html
new file mode 100644
index 0000000000..6a6bf8c748
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-alignment-001.html
@@ -0,0 +1,32 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: flex container align-items is used for flex item regardless of intermediate display: contents ancestors</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="help" href="https://drafts.csswg.org/css-align/#align-items-property">
+<link rel="match" href="display-contents-alignment-001-ref.html">
+<style>
+  .container {
+    display: flex;
+    width: 300px;
+    height: 300px;
+    align-items: center;
+    border: 2px solid purple;
+  }
+  .contents {
+    display: contents;
+    align-items: flex-start;
+  }
+  .contents > div {
+    width: 100px;
+    height: 100px;
+    background: blue;
+    align-self: auto;
+  }
+</style>
+<p>Test passes if there's a blue square vertically centered inside the box.</p>
+<div class="container">
+  <div class="contents">
+    <div></div>
+  </div>
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-alignment-002-ref.html b/testing/web-platform/tests/css/css-display/display-contents-alignment-002-ref.html
new file mode 100644
index 0000000000..f58ccf04b6
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-alignment-002-ref.html
@@ -0,0 +1,23 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test Reference</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<style>
+  .container {
+    display: grid;
+    width: 300px;
+    height: 300px;
+    justify-items: center;
+    border: 2px solid purple;
+  }
+  .container > div {
+    width: 100px;
+    height: 100px;
+    background: blue;
+    justify-self: auto;
+  }
+</style>
+<p>Test passes if there's a blue square horizontally centered inside the box.</p>
+<div class="container">
+  <div></div>
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-alignment-002.html b/testing/web-platform/tests/css/css-display/display-contents-alignment-002.html
new file mode 100644
index 0000000000..d8fa0d9efe
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-alignment-002.html
@@ -0,0 +1,32 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: grid container justify-items is used for grid item regardless of intermediate display: contents ancestors</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="help" href="https://drafts.csswg.org/css-align/#justify-items-property">
+<link rel="match" href="display-contents-alignment-002-ref.html">
+<style>
+  .container {
+    display: grid;
+    width: 300px;
+    height: 300px;
+    justify-items: center;
+    border: 2px solid purple;
+  }
+  .contents {
+    display: contents;
+    justify-items: start;
+  }
+  .contents > div {
+    width: 100px;
+    height: 100px;
+    background: blue;
+    justify-self: auto;
+  }
+</style>
+<p>Test passes if there's a blue square horizontally centered inside the box.</p>
+<div class="container">
+  <div class="contents">
+    <div></div>
+  </div>
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-before-after-001.html b/testing/web-platform/tests/css/css-display/display-contents-before-after-001.html
new file mode 100644
index 0000000000..65fc9fee84
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-before-after-001.html
@@ -0,0 +1,21 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: Generated ::before and ::after on display:contents</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:rune@opera.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-pass-ref.html">
+<style>
+    /* Disable kerning because kerning may differ for different node tree. */
+    html { font-kerning: none; font-feature-settings: "kern" off; }
+    div { display: contents }
+    .p::before { content: "P" }
+    .a::before { content: "A" }
+    .s::after { content: "S" }
+</style>
+<p>You should see the word PASS below.</p>
+<div><!--
+ --><div><div class="p"></div></div><!--
+ --><div></div><!--
+ --><div class="a"></div><!--
+ --><div>S<div class="s"></div></div>
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-before-after-002.html b/testing/web-platform/tests/css/css-display/display-contents-before-after-002.html
new file mode 100644
index 0000000000..5860a73c3d
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-before-after-002.html
@@ -0,0 +1,22 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: Generated ::before and ::after with display:contents</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:rune@opera.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-pass-ref.html">
+<style>
+    /* Disable kerning because kerning may differ for different node tree. */
+    html { font-kerning: none; font-feature-settings: "kern" off; }
+    div::before {
+        display: contents;
+        border: 100px solid red;
+        content: "P"
+    }
+    div::after {
+        display: contents;
+        border: 100px solid red;
+        content: "S"
+    }
+</style>
+<p>You should see the word PASS below.</p>
+<div>A<span>S</span></div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-before-after-003.html b/testing/web-platform/tests/css/css-display/display-contents-before-after-003.html
new file mode 100644
index 0000000000..30451426cf
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-before-after-003.html
@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: Generated ::before and ::after with display:contents inside flex</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:futhark@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-pass-ref.html">
+<style>
+    /* Disable kerning because kerning may differ for different node tree. */
+    html { font-kerning: none; font-feature-settings: "kern" off; }
+    .flex { display: inline-flex; flex-direction: column }
+    .flex::before { display: contents; content: "A" }
+    .flex::after { display: contents; content: "S" }
+</style>
+<!-- The before and after pseudo elements do not generate boxes due to
+     display:contents, so that their generated text content constitutes a
+     contiguous sequence of child text runs which means they end up in the same
+     flex item. -->
+<p>You should see the word PASS below.</p>
+P<div class="flex"></div>S
diff --git a/testing/web-platform/tests/css/css-display/display-contents-block-001.html b/testing/web-platform/tests/css/css-display/display-contents-block-001.html
new file mode 100644
index 0000000000..5a5a4f9e6c
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-block-001.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: display:contents in block layout</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:rune@opera.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-pass-no-red-ref.html">
+<style>
+    #contents {
+        display: contents;
+        border: 10px solid red
+    }
+</style>
+<p>You should see the word PASS and no red below.</p>
+<div>
+    <div id="contents">
+        <div id="inner">P<span>A</span>S<span>S</span></div>
+    </div>
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-block-002-ref.html b/testing/web-platform/tests/css/css-display/display-contents-block-002-ref.html
new file mode 100644
index 0000000000..2e7105f919
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-block-002-ref.html
@@ -0,0 +1,6 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Reftest Reference</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:rune@opera.com">
+<p>You should see the word PASS with a 300px top margin below.</p>
+<div style="margin-top: 300px">PASS</div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-block-002.html b/testing/web-platform/tests/css/css-display/display-contents-block-002.html
new file mode 100644
index 0000000000..2dd8a10b5e
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-block-002.html
@@ -0,0 +1,20 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: margin collapsing through display:contents</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:rune@opera.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-block-002-ref.html">
+<style>
+    #outer { margin-top: 100px }
+    #inner { margin-top: 300px }
+    #contents {
+        display: contents;
+        margin-top: 2000px
+    }
+</style>
+<p>You should see the word PASS with a 300px top margin below.</p>
+<div id="outer">
+    <div id="contents">
+        <div id="inner">PASS</div>
+    </div>
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-blockify-dynamic.html b/testing/web-platform/tests/css/css-display/display-contents-blockify-dynamic.html
new file mode 100644
index 0000000000..a1e09affc8
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-blockify-dynamic.html
@@ -0,0 +1,34 @@
+<!doctype html>
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1561283">
+<link rel="help" href="https://drafts.csswg.org/css-display/#valdef-display-contents">
+<link rel="help" href="https://drafts.csswg.org/css-grid/#grid-item-display">
+<link rel="author" href="https://mozilla.org" title="Mozilla">
+<link rel="author" href="mailto:emilio@crisal.io" title="Emilio Cobos Álvarez">
+<link rel="author" href="mailto:obrufau@igalia.com" title="Oriol Brufau">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<style>
+  .grid { display: grid }
+</style>
+<div style="display: grid">
+  <span id="grid-child">
+    <span></span>
+  </div>
+</div>
+<script>
+function display(el) {
+  return getComputedStyle(el).display;
+}
+test(function() {
+  let child = document.getElementById("grid-child");
+  let grandChild = child.firstElementChild;
+  assert_equals(display(child), "block", "Grid child should get blockified");
+  assert_equals(display(grandChild), "inline", "Grid grand-child should not get initially blockified");
+  child.style.display = "contents";
+  assert_equals(display(child), "contents", "No reason for it not to become display: contents");
+  assert_equals(display(grandChild), "block", "Grid grand-child with display: contents parent should get blockified");
+  child.style.display = "";
+  assert_equals(display(child), "block", "Grid child should get blockified");
+  assert_equals(display(grandChild), "inline", "Grid grand-child should get un-blockified when its parent's display stops being `contents`");
+}, "Dynamic changes to `display` causing blockification of children are handled correctly");
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-button.html b/testing/web-platform/tests/css/css-display/display-contents-button.html
new file mode 100644
index 0000000000..3711972a27
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-button.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: display:contents and HTML button element</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:futhark@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-display/#unbox-html">
+<link rel="match" href="display-contents-pass-ref.html">
+<style>
+  /* Disable kerning because kerning may differ for different node tree. */
+  html { font-kerning: none; font-feature-settings: "kern" off; }
+  button {
+    all: initial;
+    font-kerning: none; font-feature-settings: "kern" off;
+    border: 10px solid red;
+    display: contents;
+  }
+</style>
+<p>You should see the word PASS below.</p>
+<button>P<!---->A<!---->S<!---->S</button>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-computed-style.html b/testing/web-platform/tests/css/css-display/display-contents-computed-style.html
new file mode 100644
index 0000000000..2bc63701f6
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-computed-style.html
@@ -0,0 +1,61 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: Computed style for display:contents</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:rune@opera.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#transformations">
+<link rel="help" href="https://drafts.csswg.org/cssom-1/#resolved-values">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<style>
+    html, .contents { display: contents }
+
+    #t2 .contents { background-color: green }
+    #t2 span { background-color: inherit }
+
+    #t3 .contents { color: green }
+
+    #t4 {
+        width: auto;
+        height: 50%;
+        margin-left: 25%;
+        padding-top: 10%;
+    }
+</style>
+<div id="t1" class="contents"></div>
+<div id="t2">
+    <div class="contents">
+        <span></span>
+    </div>
+</div>
+<div id="t3">
+    <div class="contents">
+        <span></span>
+    </div>
+</div>
+<div id="t4" class="contents"></div>
+<script>
+    test(function(){
+        assert_equals(getComputedStyle(document.querySelector("#t1")).display, "contents");
+    }, "Serialization of computed style value for display:contents");
+
+    test(function(){
+        assert_equals(getComputedStyle(document.querySelector("#t2 span")).backgroundColor, "rgb(0, 128, 0)");
+    }, "display:contents element as inherit parent - explicit inheritance");
+
+    test(function(){
+        assert_equals(getComputedStyle(document.querySelector("#t3 span")).color, "rgb(0, 128, 0)");
+    }, "display:contents element as inherit parent - implicit inheritance");
+
+    test(function(){
+        var computed = getComputedStyle(document.querySelector("#t4"));
+        assert_equals(computed.width, "auto");
+        assert_equals(computed.height, "50%");
+        assert_equals(computed.marginLeft, "25%");
+        assert_equals(computed.paddingTop, "10%");
+    }, "Resolved value should be computed value, not used value, for display:contents");
+
+    test(function(){
+        assert_equals(getComputedStyle(document.documentElement).display, "block");
+    }, "display:contents is blockified for root elements");
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-details-001-ref.html b/testing/web-platform/tests/css/css-display/display-contents-details-001-ref.html
new file mode 100644
index 0000000000..fc078b8150
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-details-001-ref.html
@@ -0,0 +1,10 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test Reference</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
+<details>
+  <div>
+    <summary>summary</summary>
+    details
+  </div>
+</details>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-details-001.html b/testing/web-platform/tests/css/css-display/display-contents-details-001.html
new file mode 100644
index 0000000000..b1cefa6ffd
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-details-001.html
@@ -0,0 +1,12 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: display: contents under a details element doesn't prevent content from getting suppressed</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-details-001-ref.html">
+<details>
+  <div style="display:contents">
+    <summary>summary</summary>
+    details
+  </div>
+</details>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-details.html b/testing/web-platform/tests/css/css-display/display-contents-details.html
new file mode 100644
index 0000000000..0dcda91ab3
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-details.html
@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: display:contents and HTML details and summary elements</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:futhark@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-display/#unbox-html">
+<link rel="match" href="display-contents-pass-ref.html">
+<style>
+  html { font-kerning: none; font-feature-settings: "kern" off; }
+  details, summary {
+    all: initial;
+    border: 10px solid red;
+    display: contents;
+  }
+</style>
+<p>You should see the word PASS below.</p>
+P<details open><summary>A</summary><span>S</span></details>S
diff --git a/testing/web-platform/tests/css/css-display/display-contents-dynamic-before-after-001.html b/testing/web-platform/tests/css/css-display/display-contents-dynamic-before-after-001.html
new file mode 100644
index 0000000000..b8dc4ba1e8
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-dynamic-before-after-001.html
@@ -0,0 +1,25 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: Dynamic changes to ::before and ::after on display:contents</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-pass-green-no-red-ref.html">
+<style>
+    div { display: contents; color: green; }
+    .p::before { content: "P" }
+    .a::before { content: "A" }
+    .s::after { content: "S" }
+    div::before { color: red; display: contents; border: 1px solid red; }
+    .active div::before { color: green; }
+</style>
+<p>You should see the word PASS in green and no red below.</p>
+<div><!--
+ --><div><div class="p"></div></div><!--
+ --><div></div><!--
+ --><div class="a"></div><!--
+ --><div>S<div class="s"></div></div>
+</div>
+<script>
+document.body.offsetTop;
+document.body.className = "active";
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-dynamic-before-after-first-letter-001.html b/testing/web-platform/tests/css/css-display/display-contents-dynamic-before-after-first-letter-001.html
new file mode 100644
index 0000000000..7684a4b900
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-dynamic-before-after-first-letter-001.html
@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: Dynamic changes to ::before and ::after on display:contents when ::first-letter is in effect</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-pass-green-no-red-ref.html">
+<style>
+    div { color: blue; }
+    div::first-letter { color: red; }
+    div::before { display: contents; content: "PASS"; border: 1px solid red; }
+    .active div::before,
+    .active div::first-letter { color: green; }
+</style>
+<p>You should see the word PASS in green and no red below.</p>
+<div></div>
+<script>
+document.body.offsetTop;
+document.body.className = "active";
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-dynamic-fieldset-legend-001-ref.html b/testing/web-platform/tests/css/css-display/display-contents-dynamic-fieldset-legend-001-ref.html
new file mode 100644
index 0000000000..a3998524f9
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-dynamic-fieldset-legend-001-ref.html
@@ -0,0 +1,83 @@
+<!doctype html>
+<title>Reference: display:contents on fieldset/legend</title>
+<link rel="author" title="Mats Palmgren" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1694459">
+<style>
+  body { font-size: 10px; }
+  fieldset {
+    border:1px solid;
+    padding: 1px 0;
+  }
+</style>
+<fieldset>
+<fieldset id='test1'>
+<legend>LEGEND</legend>
+</fieldset>
+</fieldset>
+
+<fieldset>
+<fieldset id='test2'>
+<legend>LEGEND</legend>
+</fieldset>
+</fieldset>
+
+<fieldset>
+<legend>OUTER LEGEND</legend>
+<fieldset id='test3'>
+<legend>INNER LEGEND</legend>
+</fieldset>
+</fieldset>
+
+<fieldset>
+<legend id='test4'>LEGEND</legend>
+<legend>NOT LEGEND</legend>
+</fieldset>
+
+<fieldset>
+<legend>LEGEND</legend>
+<legend id='test5'>NOT LEGEND</legend>
+</fieldset>
+
+<fieldset>
+<legend id='test6'>LEGEND</legend>
+<legend>NOT LEGEND</legend>
+</fieldset>
+
+<fieldset>
+<legend>LEGEND</legend>
+<legend>NOT LEGEND</legend>
+</fieldset>
+
+<fieldset>
+<legend>LEGEND</legend>
+</fieldset>
+
+<fieldset>
+<div id='test9'><legend>NOT LEGEND</legend></div>
+</fieldset>
+
+<fieldset>
+<legend>LEGEND</legend>
+<div>NOT LEGEND</div>
+</fieldset>
+
+<fieldset id='test11'>
+<legend>LEGEND</legend>
+<legend>NOT LEGEND</legend>
+</fieldset>
+
+<fieldset>
+<legend id='test12'>LEGEND</legend>
+</fieldset>
+
+<fieldset>
+<legend id='test13'>LEGEND</legend>
+</fieldset>
+
+<fieldset>
+    <legend>LEGEND</legend>
+    <legend>NOT LEGEND</legend>
+</fieldset>
+
+<fieldset>
+    <legend>LEGEND</legend>
+</fieldset>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-dynamic-fieldset-legend-001.html b/testing/web-platform/tests/css/css-display/display-contents-dynamic-fieldset-legend-001.html
new file mode 100644
index 0000000000..a17828bd7a
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-dynamic-fieldset-legend-001.html
@@ -0,0 +1,171 @@
+<!doctype html>
+<title>CSS Display Module Test: display:contents on fieldset/legend</title>
+<link rel="author" title="Mats Palmgren" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1694459">
+<link rel="help" href="https://drafts.csswg.org/css-display/#box-generation">
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1694459">
+<link rel="match" href="display-contents-dynamic-fieldset-legend-001-ref.html">
+<style>
+  body { font-size: 10px; }
+  fieldset {
+    border:1px solid;
+    padding: 1px 0;
+  }
+  #test10 { padding: 0; }
+</style>
+<script>
+window.onload = () => {
+  document.body.getClientRects();
+  o = document.getElementById("test1")
+  o.setAttribute("style", "display:contents")
+  o.getClientRects()
+  o.style.cssText = ""
+  o.getClientRects()
+
+  o = document.getElementById("test2")
+  o.setAttribute("style", "")
+  o.getClientRects()
+
+  o = document.getElementById("test3")
+  o.setAttribute("style", "")
+  o.getClientRects()
+
+  o = document.getElementById("test4")
+  o.setAttribute("style", "")
+  o.getClientRects()
+
+  o = document.getElementById("test5")
+  o.setAttribute("style", "")
+  o.getClientRects()
+
+  o = document.getElementById("test6")
+  o.setAttribute("style", "")
+  o.getClientRects()
+
+  o = document.getElementById("test7")
+  o.setAttribute("style", "display:contents")
+  o.getClientRects()
+
+  o = document.getElementById("test8")
+  o.setAttribute("style", "display:contents")
+  o.getClientRects()
+
+  o = document.getElementById("test9")
+  o.setAttribute("style", "display:contents")
+  o.getClientRects()
+  o.style.cssText = ""
+  o.getClientRects()
+
+  o = document.getElementById("test10")
+  o.setAttribute("style", "display:contents")
+  o.getClientRects()
+
+  o = document.getElementById("test11")
+  set = document.createDocumentFragment()
+  set.append(document.createElement("div"))
+  legend = document.createElement("legend")
+  legend.append(document.createTextNode("LEGEND"))
+  set.append(legend)
+  legend = document.createElement("legend")
+  legend.append(document.createTextNode("NOT LEGEND"))
+  set.append(legend)
+  o.append(set)
+  o.getClientRects()
+
+  o = document.getElementById("test12")
+  o.setAttribute("style", "")
+  o.getClientRects()
+
+  o = document.getElementById("test13")
+  o.setAttribute("style", "")
+  o.getClientRects()
+
+  o = document.getElementById("test14");
+  o.appendChild(document.createElement('legend')).textContent = "LEGEND";
+  o.getClientRects();
+
+  o = document.getElementById("test15");
+  o.textContent = "";
+  o.getClientRects()
+}
+</script>
+<fieldset>
+<fieldset id='test1'>
+<legend>LEGEND</legend>
+</fieldset>
+</fieldset>
+
+<fieldset>
+<fieldset id='test2' style="display:contents">
+<legend>LEGEND</legend>
+</fieldset>
+</fieldset>
+
+<fieldset>
+<legend>OUTER LEGEND</legend>
+<fieldset id='test3' style="display:contents">
+<legend>INNER LEGEND</legend>
+</fieldset>
+</fieldset>
+
+<fieldset>
+<fieldset style="display:contents">
+<legend id='test4' style="display:contents">LEGEND</legend>
+<legend>NOT LEGEND</legend>
+</fieldset>
+</fieldset>
+
+<fieldset>
+<legend>LEGEND</legend>
+<fieldset style="display:contents">
+<legend id='test5' style="display:contents">NOT LEGEND</legend>
+</fieldset>
+</fieldset>
+
+<fieldset>
+<legend id='test6' style="display:contents">LEGEND</legend>
+<fieldset style="display:contents">
+<legend>NOT LEGEND</legend>
+</fieldset>
+</fieldset>
+
+<fieldset>
+<div id='test7'><legend>LEGEND</legend></div>
+<legend>NOT LEGEND</legend>
+</fieldset>
+
+<fieldset>
+<fieldset style="display:contents">
+<div id='test8'><legend>LEGEND</legend></div>
+</fieldset>
+</fieldset>
+
+<fieldset>
+<fieldset style="display:contents">
+<div id='test9'><legend>NOT LEGEND</legend></div>
+</fieldset>
+</fieldset>
+
+<fieldset>
+<div style="display:contents"><legend id='test10'>NOT LEGEND</legend></div>
+<legend>LEGEND</legend>
+</fieldset>
+
+<fieldset id='test11'></fieldset>
+
+<fieldset>
+    <legend id='test12' style="display:none">LEGEND</legend>
+</fieldset>
+
+<fieldset>
+    <div style="display:contents"><legend id='test13' style="display:none">LEGEND</legend></div>
+</fieldset>
+
+<fieldset>
+    <div style="display:contents"><div style="display:contents" id="test14"></div></div>
+    <legend>NOT LEGEND</legend>
+</fieldset>
+
+<fieldset>
+    <div style="display:contents"><div style="display:contents" id="test15"><legend>NOT LEGEND</legend></div></div>
+    <legend>LEGEND</legend>
+</fieldset>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-dynamic-flex-001-inline.html b/testing/web-platform/tests/css/css-display/display-contents-dynamic-flex-001-inline.html
new file mode 100644
index 0000000000..2d797795b0
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-dynamic-flex-001-inline.html
@@ -0,0 +1,39 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display 3: Display contents reattachment works well in a flex container</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-flex-001-ref.html">
+<script src="support/util.js"></script>
+<style>
+.flex {
+  display: flex;
+}
+.inline {
+  display: inline;
+}
+.contents {
+  display: contents;
+  border: 1px solid red;
+}
+</style>
+<p>Test passes if you see the word "PASS", with a "0" under the first "S", and no red</p>
+<div class="flex">
+P
+  <div class="contents">
+    <div>A</div>
+  </div>
+  <div class="contents">
+    <div class="inline">S<div>0</div></div>
+  </div>
+  <div class="contents">
+    S
+  </div>
+</div>
+<script>
+window.onload = function() {
+  eachDisplayContentsElementIn(document, window,
+      function(e) { e.style.display = 'inline'; },
+      function(e) { e.style.display = ''; })
+}
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-dynamic-flex-001-none.html b/testing/web-platform/tests/css/css-display/display-contents-dynamic-flex-001-none.html
new file mode 100644
index 0000000000..bf2af1a5b2
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-dynamic-flex-001-none.html
@@ -0,0 +1,39 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display 3: Display contents reattachment works well in a flex container</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-flex-001-ref.html">
+<script src="support/util.js"></script>
+<style>
+.flex {
+  display: flex;
+}
+.inline {
+  display: inline;
+}
+.contents {
+  display: contents;
+  border: 1px solid red;
+}
+</style>
+<p>Test passes if you see the word "PASS", with a "0" under the first "S", and no red</p>
+<div class="flex">
+P
+  <div class="contents">
+    <div>A</div>
+  </div>
+  <div class="contents">
+    <div class="inline">S<div>0</div></div>
+  </div>
+  <div class="contents">
+    S
+  </div>
+</div>
+<script>
+window.onload = function() {
+  eachDisplayContentsElementIn(document, window,
+      function(e) { e.style.display = 'none'; },
+      function(e) { e.style.display = ''; })
+}
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-dynamic-flex-002-inline.html b/testing/web-platform/tests/css/css-display/display-contents-dynamic-flex-002-inline.html
new file mode 100644
index 0000000000..a31d923150
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-dynamic-flex-002-inline.html
@@ -0,0 +1,33 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: CSS display: contents in flex layout</title>
+<!-- Imported from: https://bugzilla.mozilla.org/show_bug.cgi?id=907396 -->
+<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-flex-002-ref.html">
+<link rel="stylesheet" href="support/acid.css">
+<script src="support/util.js"></script>
+<div class="flex c1">
+  0
+  <div class="contents c1">x</div>
+  <div class="contents c1"><div class="contents c2">y</div></div>
+  <div class="contents c1"><div class="contents c2"><div>1<span class="b">1</span></div></div></div>
+  <div class="contents c2"><div class="inline">2a<div>2<div class="contents c2">b<span class="b">b</span></div></div></div></div>
+  <div class="contents c3"><div class="inline">3</div></div>
+  <div class="inline"><div class="contents c4">4</div></div>
+  <div><div class="contents c5">5a</div></div>
+  <div class="c5">5b</div>
+  <div class="contents c6"><div>6</div></div>
+  <div class="ib"><div class="contents c7"><div class="contents c2">7<span class="b">a</span></div></div></div>
+  <div class="contents c9"><div>8</div></div>
+  <div class="contents c9"><div class="contents">9<div class="contents c2">a<span class="b">b</span>c</div></div></div>
+  <div class="contents c10"><div>10</div></div>
+</div>
+<script>
+window.onload = function() {
+  eachDisplayContentsElementIn(document, window,
+      function(e) { e.style.display = 'inline'; },
+      function(e) { e.style.display = ''; })
+}
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-dynamic-flex-002-none.html b/testing/web-platform/tests/css/css-display/display-contents-dynamic-flex-002-none.html
new file mode 100644
index 0000000000..64fbf03b8a
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-dynamic-flex-002-none.html
@@ -0,0 +1,33 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: CSS display: contents in flex layout</title>
+<!-- Imported from: https://bugzilla.mozilla.org/show_bug.cgi?id=907396 -->
+<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-flex-002-ref.html">
+<link rel="stylesheet" href="support/acid.css">
+<script src="support/util.js"></script>
+<div class="flex c1">
+  0
+  <div class="contents c1">x</div>
+  <div class="contents c1"><div class="contents c2">y</div></div>
+  <div class="contents c1"><div class="contents c2"><div>1<span class="b">1</span></div></div></div>
+  <div class="contents c2"><div class="inline">2a<div>2<div class="contents c2">b<span class="b">b</span></div></div></div></div>
+  <div class="contents c3"><div class="inline">3</div></div>
+  <div class="inline"><div class="contents c4">4</div></div>
+  <div><div class="contents c5">5a</div></div>
+  <div class="c5">5b</div>
+  <div class="contents c6"><div>6</div></div>
+  <div class="ib"><div class="contents c7"><div class="contents c2">7<span class="b">a</span></div></div></div>
+  <div class="contents c9"><div>8</div></div>
+  <div class="contents c9"><div class="contents">9<div class="contents c2">a<span class="b">b</span>c</div></div></div>
+  <div class="contents c10"><div>10</div></div>
+</div>
+<script>
+window.onload = function() {
+  eachDisplayContentsElementIn(document, window,
+      function(e) { e.style.display = 'none'; },
+      function(e) { e.style.display = ''; })
+}
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-dynamic-flex-003-inline.html b/testing/web-platform/tests/css/css-display/display-contents-dynamic-flex-003-inline.html
new file mode 100644
index 0000000000..435a10a724
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-dynamic-flex-003-inline.html
@@ -0,0 +1,33 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: CSS display: contents in flex layout</title>
+<!-- Imported from: https://bugzilla.mozilla.org/show_bug.cgi?id=907396 -->
+<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-flex-002-ref.html">
+<link rel="stylesheet" href="support/acid.css">
+<script src="support/util.js"></script>
+<div class="flex"><div class="contents c1">
+  0
+  <div class="contents c1">x</div>
+  <div class="contents c1"><div class="contents c2">y</div></div>
+  <div class="contents c1"><div class="contents c2"><div>1<span class="b">1</span></div></div></div>
+  <div class="contents c2"><div class="inline">2a<div>2<div class="contents c2">b<span class="b">b</span></div></div></div></div>
+  <div class="contents c3"><div class="inline">3</div></div>
+  <div><div class="contents c4">4</div></div>
+  <div><div class="contents c5">5a</div></div>
+  <div class="c5">5b</div>
+  <div class="contents c6"><div>6</div></div>
+  <div class="ib"><div class="contents c7"><div class="contents c2">7<span class="b">a</span></div></div></div>
+  <div class="contents c9"><div>8</div></div>
+  <div class="contents c9"><div class="contents">9<div class="contents c2">a<span class="b">b</span>c</div></div></div>
+  <div class="contents c10"><div>10</div></div>
+</div></div>
+<script>
+window.onload = function() {
+  eachDisplayContentsElementIn(document, window,
+      function(e) { e.style.display = 'inline'; },
+      function(e) { e.style.display = ''; })
+}
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-dynamic-flex-003-none.html b/testing/web-platform/tests/css/css-display/display-contents-dynamic-flex-003-none.html
new file mode 100644
index 0000000000..5c357c1632
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-dynamic-flex-003-none.html
@@ -0,0 +1,33 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: CSS display: contents in flex layout</title>
+<!-- Imported from: https://bugzilla.mozilla.org/show_bug.cgi?id=907396 -->
+<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-flex-002-ref.html">
+<link rel="stylesheet" href="support/acid.css">
+<script src="support/util.js"></script>
+<div class="flex"><div class="contents c1">
+  0
+  <div class="contents c1">x</div>
+  <div class="contents c1"><div class="contents c2">y</div></div>
+  <div class="contents c1"><div class="contents c2"><div>1<span class="b">1</span></div></div></div>
+  <div class="contents c2"><div class="inline">2a<div>2<div class="contents c2">b<span class="b">b</span></div></div></div></div>
+  <div class="contents c3"><div class="inline">3</div></div>
+  <div><div class="contents c4">4</div></div>
+  <div><div class="contents c5">5a</div></div>
+  <div class="c5">5b</div>
+  <div class="contents c6"><div>6</div></div>
+  <div class="ib"><div class="contents c7"><div class="contents c2">7<span class="b">a</span></div></div></div>
+  <div class="contents c9"><div>8</div></div>
+  <div class="contents c9"><div class="contents">9<div class="contents c2">a<span class="b">b</span>c</div></div></div>
+  <div class="contents c10"><div>10</div></div>
+</div></div>
+<script>
+window.onload = function() {
+  eachDisplayContentsElementIn(document, window,
+      function(e) { e.style.display = 'none'; },
+      function(e) { e.style.display = ''; })
+}
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-dynamic-generated-content-fieldset-001-ref.html b/testing/web-platform/tests/css/css-display/display-contents-dynamic-generated-content-fieldset-001-ref.html
new file mode 100644
index 0000000000..651bc19b83
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-dynamic-generated-content-fieldset-001-ref.html
@@ -0,0 +1,16 @@
+<!doctype html>
+<meta charset="utf-8">
+<title>CSS Reftest Reference</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
+<style>
+div {
+  display: contents;
+  border: 10px solid red;
+}
+</style>
+<p>
+  Test passes if there is no red text and no red border.
+</p>
+<fieldset>
+  <div></div>
+</fieldset>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-dynamic-generated-content-fieldset-001.html b/testing/web-platform/tests/css/css-display/display-contents-dynamic-generated-content-fieldset-001.html
new file mode 100644
index 0000000000..8f8a0ba479
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-dynamic-generated-content-fieldset-001.html
@@ -0,0 +1,26 @@
+<!doctype html>
+<meta charset="utf-8">
+<title>CSS Test: Dynamic changes to display: contents generated content in fieldsets.</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-dynamic-generated-content-fieldset-001-ref.html">
+<style>
+.after::after {
+  content: "FAIL";
+  color: red;
+}
+div {
+  display: contents;
+  border: 10px solid red;
+}
+</style>
+<p>
+  Test passes if there is no red text and no red border.
+</p>
+<fieldset>
+  <div class="after"></div>
+</fieldset>
+<script>
+document.body.offsetHeight;
+document.querySelector("div").classList.remove("after");
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-dynamic-inline-flex-001-inline.html b/testing/web-platform/tests/css/css-display/display-contents-dynamic-inline-flex-001-inline.html
new file mode 100644
index 0000000000..f14e133a04
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-dynamic-inline-flex-001-inline.html
@@ -0,0 +1,47 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: CSS display: contents in inline-flex layout</title>
+<!-- Imported from: https://bugzilla.mozilla.org/show_bug.cgi?id=907396 -->
+<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-inline-flex-001-ref.html">
+<link rel="stylesheet" href="support/acid.css">
+<script src="support/util.js"></script>
+<div style="color: red">
+  <div class="iflex"><div class="contents c2">
+  0
+  </div></div>
+  <div class="iflex"><div class="contents c2">
+  0
+  <div class="contents c1">1</div>
+  2
+  </div></div>
+  <div class="iflex"><div class="contents c2">
+  0
+  <div class="c1">1</div>
+  2
+  </div></div>
+  <div class="iflex c3">
+  0
+  <div class="contents c2"><div class="c1">1</div></div>
+  2
+  </div>
+  <div class="iflex c3">
+  <div class="contents c2">0</div>
+  <div class="contents c2"><div class="c1">1</div></div>
+  <div class="contents c2">2</div>
+  </div>
+  <div class="iflex c3">
+  <div class="inline">0</div>
+  <div class="contents"><div class="inline c1">1</div></div>
+  <div class="inline">2</div>
+  </div>
+</div>
+<script>
+window.onload = function() {
+  eachDisplayContentsElementIn(document, window,
+      function(e) { e.style.display = 'none'; },
+      function(e) { e.style.display = ''; })
+}
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-dynamic-inline-flex-001-none.html b/testing/web-platform/tests/css/css-display/display-contents-dynamic-inline-flex-001-none.html
new file mode 100644
index 0000000000..f14e133a04
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-dynamic-inline-flex-001-none.html
@@ -0,0 +1,47 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: CSS display: contents in inline-flex layout</title>
+<!-- Imported from: https://bugzilla.mozilla.org/show_bug.cgi?id=907396 -->
+<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-inline-flex-001-ref.html">
+<link rel="stylesheet" href="support/acid.css">
+<script src="support/util.js"></script>
+<div style="color: red">
+  <div class="iflex"><div class="contents c2">
+  0
+  </div></div>
+  <div class="iflex"><div class="contents c2">
+  0
+  <div class="contents c1">1</div>
+  2
+  </div></div>
+  <div class="iflex"><div class="contents c2">
+  0
+  <div class="c1">1</div>
+  2
+  </div></div>
+  <div class="iflex c3">
+  0
+  <div class="contents c2"><div class="c1">1</div></div>
+  2
+  </div>
+  <div class="iflex c3">
+  <div class="contents c2">0</div>
+  <div class="contents c2"><div class="c1">1</div></div>
+  <div class="contents c2">2</div>
+  </div>
+  <div class="iflex c3">
+  <div class="inline">0</div>
+  <div class="contents"><div class="inline c1">1</div></div>
+  <div class="inline">2</div>
+  </div>
+</div>
+<script>
+window.onload = function() {
+  eachDisplayContentsElementIn(document, window,
+      function(e) { e.style.display = 'none'; },
+      function(e) { e.style.display = ''; })
+}
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-dynamic-list-001-inline.html b/testing/web-platform/tests/css/css-display/display-contents-dynamic-list-001-inline.html
new file mode 100644
index 0000000000..f44ee28fd2
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-dynamic-list-001-inline.html
@@ -0,0 +1,35 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: CSS display: contents in list layout</title>
+<!-- Imported from: https://bugzilla.mozilla.org/show_bug.cgi?id=907396 -->
+<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-list-001-ref.html">
+<link rel="stylesheet" href="support/acid.css">
+<script src="support/util.js"></script>
+<div style="color: red">
+  <ul><li class="c1"><div class="contents c2">
+  0
+  <div class="contents c1">x</div>
+  <div class="contents c1"><div class="contents c2">y</div></div>
+  <div class="contents c1"><div class="contents c2"><div>1<span class="b">1</span></div></div></div>
+  <div class="contents c2"><div class="inline">2a<div>2<div class="contents c2">b<span class="b">b</span></div></div></div></div>
+  <div class="contents c3"><div class="inline">3</div></div>
+  <div class="inline"><div class="contents c4">4</div></div>
+  <div><div class="contents c5">5a</div></div>
+  <div class="c5">5b</div>
+  <div class="contents c6"><div>6</div></div>
+  <div class="ib"><div class="contents c7"><div class="contents c2">7<span class="b">a</span></div></div></div>
+  <div class="contents c9"><div>8</div></div>
+  <div class="contents c9"><div class="contents">9<div class="contents c2">a<span class="b">b</span>c</div></div></div>
+  <div class="contents c10"><div>10</div></div>
+  </div></li></ul>
+</div>
+<script>
+window.onload = function() {
+  eachDisplayContentsElementIn(document, window,
+      function(e) { e.style.display = 'inline'; },
+      function(e) { e.style.display = ''; })
+}
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-dynamic-list-001-none.html b/testing/web-platform/tests/css/css-display/display-contents-dynamic-list-001-none.html
new file mode 100644
index 0000000000..f44ee28fd2
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-dynamic-list-001-none.html
@@ -0,0 +1,35 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: CSS display: contents in list layout</title>
+<!-- Imported from: https://bugzilla.mozilla.org/show_bug.cgi?id=907396 -->
+<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-list-001-ref.html">
+<link rel="stylesheet" href="support/acid.css">
+<script src="support/util.js"></script>
+<div style="color: red">
+  <ul><li class="c1"><div class="contents c2">
+  0
+  <div class="contents c1">x</div>
+  <div class="contents c1"><div class="contents c2">y</div></div>
+  <div class="contents c1"><div class="contents c2"><div>1<span class="b">1</span></div></div></div>
+  <div class="contents c2"><div class="inline">2a<div>2<div class="contents c2">b<span class="b">b</span></div></div></div></div>
+  <div class="contents c3"><div class="inline">3</div></div>
+  <div class="inline"><div class="contents c4">4</div></div>
+  <div><div class="contents c5">5a</div></div>
+  <div class="c5">5b</div>
+  <div class="contents c6"><div>6</div></div>
+  <div class="ib"><div class="contents c7"><div class="contents c2">7<span class="b">a</span></div></div></div>
+  <div class="contents c9"><div>8</div></div>
+  <div class="contents c9"><div class="contents">9<div class="contents c2">a<span class="b">b</span>c</div></div></div>
+  <div class="contents c10"><div>10</div></div>
+  </div></li></ul>
+</div>
+<script>
+window.onload = function() {
+  eachDisplayContentsElementIn(document, window,
+      function(e) { e.style.display = 'inline'; },
+      function(e) { e.style.display = ''; })
+}
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-dynamic-multicol-001-inline.html b/testing/web-platform/tests/css/css-display/display-contents-dynamic-multicol-001-inline.html
new file mode 100644
index 0000000000..b8b2c6bb10
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-dynamic-multicol-001-inline.html
@@ -0,0 +1,32 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: CSS display:contents in multicolumn layout</title>
+<!-- Imported from: https://bugzilla.mozilla.org/show_bug.cgi?id=907396 -->
+<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-multicol-001-ref.html">
+<link rel="stylesheet" href="support/acid.css">
+<script src="support/util.js"></script>
+<div style="color: red">
+  <div class="columns">
+  <div class="contents c1"><div class="contents c2"><div>1<span class="b">1</span></div></div></div>
+  <div class="contents c2"><div>2</div></div>
+  <div class="contents c3"><div>3</div></div>
+  </div>
+
+  <div class="columns">
+  <div class="columns contents">
+  <div class="contents c1"><div class="contents c2"><div>1<span class="b">1</span></div></div></div>
+  <div class="contents c2"><div>2</div></div>
+  <div class="contents c3"><div>3</div></div>
+  </div>
+  </div>
+</div>
+<script>
+window.onload = function() {
+  eachDisplayContentsElementIn(document, window,
+      function(e) { e.style.display = 'inline'; },
+      function(e) { e.style.display = ''; })
+}
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-dynamic-multicol-001-none.html b/testing/web-platform/tests/css/css-display/display-contents-dynamic-multicol-001-none.html
new file mode 100644
index 0000000000..f171fc09fc
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-dynamic-multicol-001-none.html
@@ -0,0 +1,32 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: CSS display:contents in multicolumn layout</title>
+<!-- Imported from: https://bugzilla.mozilla.org/show_bug.cgi?id=907396 -->
+<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-multicol-001-ref.html">
+<link rel="stylesheet" href="support/acid.css">
+<script src="support/util.js"></script>
+<div style="color: red">
+  <div class="columns">
+  <div class="contents c1"><div class="contents c2"><div>1<span class="b">1</span></div></div></div>
+  <div class="contents c2"><div>2</div></div>
+  <div class="contents c3"><div>3</div></div>
+  </div>
+
+  <div class="columns">
+  <div class="columns contents">
+  <div class="contents c1"><div class="contents c2"><div>1<span class="b">1</span></div></div></div>
+  <div class="contents c2"><div>2</div></div>
+  <div class="contents c3"><div>3</div></div>
+  </div>
+  </div>
+</div>
+<script>
+window.onload = function() {
+  eachDisplayContentsElementIn(document, window,
+      function(e) { e.style.display = 'none'; },
+      function(e) { e.style.display = ''; })
+}
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-dynamic-pseudo-insertion-001-ref.html b/testing/web-platform/tests/css/css-display/display-contents-dynamic-pseudo-insertion-001-ref.html
new file mode 100644
index 0000000000..38dd74a744
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-dynamic-pseudo-insertion-001-ref.html
@@ -0,0 +1,5 @@
+<!doctype html>
+<meta charset="utf-8">
+<title>CSS Test Reference</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
+P<span>A</span>SS
diff --git a/testing/web-platform/tests/css/css-display/display-contents-dynamic-pseudo-insertion-001.html b/testing/web-platform/tests/css/css-display/display-contents-dynamic-pseudo-insertion-001.html
new file mode 100644
index 0000000000..f35c3cc47b
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-dynamic-pseudo-insertion-001.html
@@ -0,0 +1,26 @@
+<!doctype html>
+<meta charset="utf-8">
+<title>CSS Test: Dynamic insertion on empty display: contents element with pseudo-elements</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel=match href="display-contents-dynamic-pseudo-insertion-001-ref.html">
+<style>
+.contents {
+  display: contents;
+  border: 10px solid red;
+}
+.contents::before {
+  content: "A";
+}
+.contents::after {
+  content: "SS";
+}
+</style>
+<div class="contents"></div>
+<script>
+document.body.offsetTop;
+let span = document.createElement('span');
+span.innerHTML = "P";
+let contents = document.querySelector('.contents');
+contents.parentNode.insertBefore(span, contents);
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-dynamic-table-001-inline.html b/testing/web-platform/tests/css/css-display/display-contents-dynamic-table-001-inline.html
new file mode 100644
index 0000000000..4f2578cbb0
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-dynamic-table-001-inline.html
@@ -0,0 +1,33 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: CSS display:contents</title>
+<!-- Imported from: https://bugzilla.mozilla.org/show_bug.cgi?id=907396 -->
+<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-table-001-ref.html">
+<link rel="stylesheet" href="support/acid.css">
+<script src="support/util.js"></script>
+<div style="color: red">
+  <div class="contents c1"><div class="contents c2"><div class="caption">1<span class="b">1</span></div></div></div>
+  <div class="contents c2"><div class="row">2a<div class="cell">2<div class="contents c2">b<span class="b">b</span></div></div></div></div>
+  <div class="contents c3"><div class="cell">3</div></div>
+  <div class="contents c4"><div class="rowg">4</div></div>
+  <div class="contents c5"><div class="cell">5a</div></div>
+  <div class="cell c5">5b</div>
+  <div class="contents c6"><div class="head">6</div></div>
+  <div class="contents c7"><div class="cell"><div class="contents c2">7<span class="b">a</span></div></div></div>
+  <div class="contents c8"><div class="cell">7b</div></div>
+  <div class="contents c9"><div class="foot">8</div></div>
+  <div class="contents c9"><div class="foot">9<div class="contents c2">a<span class="b">b</span>c</div></div></div>
+  <div class="contents c10"><div class="cell">10</div></div>
+</div>
+<script>
+window.onload = function() {
+  eachDisplayContentsElementIn(
+      document,
+      window,
+      function(e) { e.style.display = 'inline'; },
+      function(e) { e.style.display = 'contents'; });
+}
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-dynamic-table-001-none.html b/testing/web-platform/tests/css/css-display/display-contents-dynamic-table-001-none.html
new file mode 100644
index 0000000000..eb4297d431
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-dynamic-table-001-none.html
@@ -0,0 +1,33 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: CSS display:contents</title>
+<!-- Imported from: https://bugzilla.mozilla.org/show_bug.cgi?id=907396 -->
+<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-table-001-ref.html">
+<link rel="stylesheet" href="support/acid.css">
+<script src="support/util.js"></script>
+<div style="color: red">
+  <div class="contents c1"><div class="contents c2"><div class="caption">1<span class="b">1</span></div></div></div>
+  <div class="contents c2"><div class="row">2a<div class="cell">2<div class="contents c2">b<span class="b">b</span></div></div></div></div>
+  <div class="contents c3"><div class="cell">3</div></div>
+  <div class="contents c4"><div class="rowg">4</div></div>
+  <div class="contents c5"><div class="cell">5a</div></div>
+  <div class="cell c5">5b</div>
+  <div class="contents c6"><div class="head">6</div></div>
+  <div class="contents c7"><div class="cell"><div class="contents c2">7<span class="b">a</span></div></div></div>
+  <div class="contents c8"><div class="cell">7b</div></div>
+  <div class="contents c9"><div class="foot">8</div></div>
+  <div class="contents c9"><div class="foot">9<div class="contents c2">a<span class="b">b</span>c</div></div></div>
+  <div class="contents c10"><div class="cell">10</div></div>
+</div>
+<script>
+window.onload = function() {
+  eachDisplayContentsElementIn(
+      document,
+      window,
+      function(e) { e.style.display = 'none'; },
+      function(e) { e.style.display = 'contents'; });
+}
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-dynamic-table-002-inline.html b/testing/web-platform/tests/css/css-display/display-contents-dynamic-table-002-inline.html
new file mode 100644
index 0000000000..e7a9d200d7
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-dynamic-table-002-inline.html
@@ -0,0 +1,35 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: CSS display:contents in table layout</title>
+<!-- Imported from: https://bugzilla.mozilla.org/show_bug.cgi?id=907396 -->
+<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-table-002-ref.html">
+<link rel="stylesheet" href="support/acid.css">
+<script src="support/util.js"></script>
+<div style="color: red">
+  <div class="table" style="float:right">
+    <div class="contents c1"><div class="contents c2"><div class="caption">1<span class="b">1</span></div></div></div>
+    <div class="contents c2"><div class="row">2a<div class="cell">2<div class="contents c2">b<span class="b">b</span></div></div></div></div>
+    <div class="contents c3"><div class="cell">3</div></div>
+    <div class="contents c4"><div class="rowg">4</div></div>
+    <div class="contents c5"><div class="cell">5a</div></div>
+    <div class="cell c5">5b</div>
+    <div class="contents c6"><div class="head">6</div></div>
+    <div class="contents c7"><div class="cell"><div class="contents c2">7<span class="b">a</span></div></div></div>
+    <div class="contents c8"><div class="cell">7b</div></div>
+    <div class="contents c9"><div class="foot">8</div></div>
+    <div class="contents c9"><div class="foot">9<div class="contents c2">a<span class="b">b</span>c</div></div></div>
+    <div class="contents c10"><div class="cell">10</div></div>
+  </div>
+</div>
+<script>
+window.onload = function() {
+  eachDisplayContentsElementIn(
+      document,
+      window,
+      function(e) { e.style.display = 'inline'; },
+      function(e) { e.style.display = 'contents'; });
+}
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-dynamic-table-002-none.html b/testing/web-platform/tests/css/css-display/display-contents-dynamic-table-002-none.html
new file mode 100644
index 0000000000..964b6d72f0
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-dynamic-table-002-none.html
@@ -0,0 +1,35 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: CSS display:contents in table layout</title>
+<!-- Imported from: https://bugzilla.mozilla.org/show_bug.cgi?id=907396 -->
+<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-table-002-ref.html">
+<link rel="stylesheet" href="support/acid.css">
+<script src="support/util.js"></script>
+<div style="color: red">
+  <div class="table" style="float:right">
+    <div class="contents c1"><div class="contents c2"><div class="caption">1<span class="b">1</span></div></div></div>
+    <div class="contents c2"><div class="row">2a<div class="cell">2<div class="contents c2">b<span class="b">b</span></div></div></div></div>
+    <div class="contents c3"><div class="cell">3</div></div>
+    <div class="contents c4"><div class="rowg">4</div></div>
+    <div class="contents c5"><div class="cell">5a</div></div>
+    <div class="cell c5">5b</div>
+    <div class="contents c6"><div class="head">6</div></div>
+    <div class="contents c7"><div class="cell"><div class="contents c2">7<span class="b">a</span></div></div></div>
+    <div class="contents c8"><div class="cell">7b</div></div>
+    <div class="contents c9"><div class="foot">8</div></div>
+    <div class="contents c9"><div class="foot">9<div class="contents c2">a<span class="b">b</span>c</div></div></div>
+    <div class="contents c10"><div class="cell">10</div></div>
+  </div>
+</div>
+<script>
+window.onload = function() {
+  eachDisplayContentsElementIn(
+      document,
+      window,
+      function(e) { e.style.display = 'none'; },
+      function(e) { e.style.display = 'contents'; });
+}
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-fieldset-002-ref.html b/testing/web-platform/tests/css/css-display/display-contents-fieldset-002-ref.html
new file mode 100644
index 0000000000..ff8fd9dea7
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-fieldset-002-ref.html
@@ -0,0 +1,60 @@
+<!DOCTYPE HTML>
+<html><head>
+<link rel="author" title="Mats Palmgren" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1140160">
+<style>
+fieldset { padding:0; }
+span { display:block; width:10px; height:10px; background:lime; }
+.contents { }
+legend { border: 1px solid; }
+.test2 legend { }
+.test2 legend::after, .test3 legend::after { content:"legend"; }
+.test2 legend.static, .test3 legend.static { display:block; }
+.test2 legend.static::before, .test3 legend.static::before { content:"static "; }
+.test2 legend.static::before { content:"static "; }
+.after::after { content:"::after"; }
+.before::before { content:"::before"; }
+.nb legend.static  { border: 1px solid; }
+.nb legend { border-style:none; }
+</style>
+</head>
+<body>
+<fieldset><div class="test contents"></div></fieldset>
+<fieldset><div class="test contents">x</div></fieldset>
+<fieldset><div class="test contents after"></div></fieldset>
+<fieldset><div class="test contents before"></div></fieldset>
+<fieldset><div class="test contents before after"></div></fieldset>
+<fieldset><span></span></fieldset>
+<fieldset><span></span></fieldset>
+<fieldset><span></span></fieldset>
+<fieldset class="test2"></fieldset>
+<fieldset class="test2 after"></fieldset>
+<fieldset class="test2"><legend class="static"></legend></fieldset>
+<fieldset class="test2"><legend class="static contents"></legend></fieldset>
+<fieldset class="test2"><legend class="static"></legend></fieldset>
+<fieldset class="test2"></fieldset>
+<fieldset class="test3"></fieldset>
+<fieldset class="test2"><legend class="static"></legend></fieldset>
+<fieldset class="test3"><legend class="static"></legend></fieldset>
+<script>
+document.body.offsetHeight;
+var tests = document.querySelectorAll('.test');
+for (i=0; i < tests.length; ++i) {
+  test = tests[i];
+  test.appendChild(document.createElement('span'));
+}
+var tests = document.querySelectorAll('.test2');
+for (i=0; i < tests.length; ++i) {
+  test = tests[i];
+  let span = document.createElement('dummy-inline');
+  span.innerHTML = "legend";
+  test.appendChild(span);
+}
+
+var tests = document.querySelectorAll('.test3');
+for (i=0; i < tests.length; ++i) {
+  test = tests[i];
+  test.appendChild(document.createElement('legend'));
+}
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-fieldset-002.html b/testing/web-platform/tests/css/css-display/display-contents-fieldset-002.html
new file mode 100644
index 0000000000..612d483d7c
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-fieldset-002.html
@@ -0,0 +1,52 @@
+<!DOCTYPE HTML>
+<html><head>
+<link rel="author" title="Mats Palmgren" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1140160">
+<link rel="help" href="https://drafts.csswg.org/css-display/#box-generation">
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1140160">
+<link rel="match" href="display-contents-fieldset-002-ref.html">
+<style>
+fieldset { padding:0; }
+span { display:block; width:10px; height:10px; background:lime; }
+.contents { display: contents; }
+legend { border: 1px solid; }
+.test2 legend { display:contents; }
+.test2 legend::after, .test3 legend::after { content:"legend"; }
+.test2 legend.static, .test3 legend.static { display:block; }
+.test2 legend.static::before, .test3 legend.static::before { content:"static "; }
+.after::after { content:"::after"; }
+.before::before { content:"::before"; }
+</style>
+</head>
+<body>
+<fieldset><div class="test contents"></div></fieldset>
+<fieldset><div class="test contents">x</div></fieldset>
+<fieldset><div class="test contents after"></div></fieldset>
+<fieldset><div class="test contents before"></div></fieldset>
+<fieldset><div class="test contents before after"></div></fieldset>
+<fieldset><legend class="test contents"></legend></fieldset>
+<fieldset><div class="contents"><legend class="test contents"></legend></div></fieldset>
+<fieldset><legend class="contents"><div class="test contents"></div></legend></fieldset>
+<fieldset class="test2"></fieldset>
+<fieldset class="test2 after"></fieldset>
+<fieldset class="test2"><legend class="static"></legend></fieldset>
+<fieldset class="test2"><legend class="static contents"></legend></fieldset>
+<fieldset class="test2"><div class="contents"><legend class="static"></legend></div></fieldset>
+<fieldset><div class="test2 contents"></div></fieldset>
+<fieldset><div class="test3 contents"></div></fieldset>
+<fieldset><div class="test2 contents"><legend class="static"></legend></div></fieldset>
+<fieldset><div class="test3 contents"><legend class="static"></legend></div></fieldset>
+<script>
+document.body.offsetHeight;
+var tests = document.querySelectorAll('.test');
+for (i=0; i < tests.length; ++i) {
+  test = tests[i];
+  test.appendChild(document.createElement('span'));
+}
+var tests = document.querySelectorAll('.test2,.test3');
+for (i=0; i < tests.length; ++i) {
+  test = tests[i];
+  test.appendChild(document.createElement('legend'));
+}
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-fieldset-nested-legend-ref.html b/testing/web-platform/tests/css/css-display/display-contents-fieldset-nested-legend-ref.html
new file mode 100644
index 0000000000..c4afe0e53b
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-fieldset-nested-legend-ref.html
@@ -0,0 +1,6 @@
+<!doctype html>
+<meta charset="utf-8">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
+<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+<title>CSS Test Reference</title>
+<fieldset style="color: green">P<legend>legend</legend>ASS</fieldset>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-fieldset-nested-legend.html b/testing/web-platform/tests/css/css-display/display-contents-fieldset-nested-legend.html
new file mode 100644
index 0000000000..abda0ad32d
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-fieldset-nested-legend.html
@@ -0,0 +1,25 @@
+<!doctype html>
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<meta charset="utf-8">
+<link rel="match" href="display-contents-fieldset-nested-legend-ref.html">
+<link rel="help" href="https://drafts.csswg.org/css-display/#unbox">
+<link rel="help" href="https://drafts.csswg.org/css-display/#valdef-display-contents">
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1427292">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
+<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+<title>CSS Test: display: contents on legend</title>
+<style>
+fieldset {
+  color: red;
+}
+.contents {
+  display: contents;
+  color: green;
+  border: 10px solid red;
+  unicode-bidi: normal;
+}
+</style>
+<fieldset><legend class="contents">P<legend>legend</legend>ASS</legend></fieldset>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-fieldset.html b/testing/web-platform/tests/css/css-display/display-contents-fieldset.html
new file mode 100644
index 0000000000..f38a3763cf
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-fieldset.html
@@ -0,0 +1,17 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: display:contents and HTML fieldset and legend elements</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:futhark@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-display/#unbox-html">
+<link rel="match" href="display-contents-pass-ref.html">
+<style>
+  /* Disable kerning because kerning may differ for different node tree. */
+  html { font-kerning: none; font-feature-settings: "kern" off; }
+  fieldset, legend {
+    all: initial;
+    border: 10px solid red;
+    display: contents;
+  }
+</style>
+<p>You should see the word PASS below.</p>
+P<fieldset>A<legend>S</legend>S</fieldset>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-first-letter-001.html b/testing/web-platform/tests/css/css-display/display-contents-first-letter-001.html
new file mode 100644
index 0000000000..eb645c9ee7
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-first-letter-001.html
@@ -0,0 +1,17 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: display:contents and ::first-letter</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:rune@opera.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="help" href="https://drafts.csswg.org/css-pseudo-4/#first-letter-pseudo">
+<link rel="match" href="display-contents-pass-green-no-red-ref.html">
+<style>
+    #contents { display: contents }
+    #contents::first-letter { background-color: red }
+    #container::first-letter { color: green }
+    span { color: green }
+</style>
+<p>You should see the word PASS in green and no red below.</p>
+<div id="container">
+    <div id="contents">P<span>ASS</span></div>
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-first-letter-002.html b/testing/web-platform/tests/css/css-display/display-contents-first-letter-002.html
new file mode 100644
index 0000000000..8d1d8572ac
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-first-letter-002.html
@@ -0,0 +1,14 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: display:contents and ::first-letter inheritance</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:futhark@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="help" href="https://drafts.csswg.org/css-pseudo-4/#first-letter-pseudo">
+<link rel="match" href="display-contents-pass-green-no-red-ref.html">
+<style>
+  div { color: red }
+  div::first-letter { background: transparent /* To trigger first-letter pseudo element */ }
+  span { color: green; display: contents; background-color: red }
+</style>
+<p>You should see the word PASS in green and no red below.</p>
+<div><span>PASS</span></div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-first-line-001.html b/testing/web-platform/tests/css/css-display/display-contents-first-line-001.html
new file mode 100644
index 0000000000..7fbd4b3bff
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-first-line-001.html
@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: display:contents and ::first-line</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:rune@opera.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="help" href="https://drafts.csswg.org/css-pseudo-4/#first-line-pseudo">
+<link rel="match" href="display-contents-pass-green-no-red-ref.html">
+<style>
+    #contents { display: contents }
+    #contents::first-line { background-color: red }
+    #container::first-line { color: green }
+</style>
+<p>You should see the word PASS in green and no red below.</p>
+<div id="container">
+    <div id="contents"><span>P</span>ASS</div>
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-first-line-002.html b/testing/web-platform/tests/css/css-display/display-contents-first-line-002.html
new file mode 100644
index 0000000000..ae900235a5
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-first-line-002.html
@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: display:contents and ::first-line inheritance</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:futhark@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="help" href="https://drafts.csswg.org/css-pseudo-4/#first-line-pseudo">
+<link rel="match" href="display-contents-pass-green-no-red-ref.html">
+<style>
+  span { color: green }
+  .contents { display: contents }
+  #container::first-line { color: red }
+</style>
+<p>You should see the word PASS in green and no red below.</p>
+<div id="container">
+  <span class="contents">P</span><span>ASS</span>
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-flex-001-ref.html b/testing/web-platform/tests/css/css-display/display-contents-flex-001-ref.html
new file mode 100644
index 0000000000..144af7cf9e
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-flex-001-ref.html
@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test Reference</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<style>
+.flex {
+  display: flex;
+}
+.inline {
+  display: inline;
+}
+</style>
+<p>Test passes if you see the word "PASS", with a "0" under the first "S", and no red</p>
+<div class="flex">
+P
+  <div>A</div>
+  <div class="inline">S<div>0</div></div>
+  S
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-flex-001.html b/testing/web-platform/tests/css/css-display/display-contents-flex-001.html
new file mode 100644
index 0000000000..da4cd72008
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-flex-001.html
@@ -0,0 +1,31 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: display: contents inside a flex container</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-flex-001-ref.html">
+<style>
+.flex {
+  display: flex;
+}
+.inline {
+  display: inline;
+}
+.contents {
+  display: contents;
+  border: 1px solid red;
+}
+</style>
+<p>Test passes if you see the word "PASS", with a "0" under the first "S", and no red</p>
+<div class="flex">
+P
+  <div class="contents">
+    <div>A</div>
+  </div>
+  <div class="contents">
+    <div class="inline">S<div>0</div></div>
+  </div>
+  <div class="contents">
+    S
+  </div>
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-flex-002-ref.html b/testing/web-platform/tests/css/css-display/display-contents-flex-002-ref.html
new file mode 100644
index 0000000000..3624bb782d
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-flex-002-ref.html
@@ -0,0 +1,27 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Reftest Reference</title>
+<!-- Imported from: https://bugzilla.mozilla.org/show_bug.cgi?id=907396 -->
+<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="stylesheet" href="support/acid.css">
+<div style="color: red" class="ref">
+  <div class="flex c1">
+    0&nbsp;
+    <div class="inline c1">x&nbsp;</div>
+    <div class="inline c1"><div class="inline c2">y</div></div>
+    <div class="inline c1"><div class="inline c2"><div>1<span>1</span></div></div></div>
+    <div class="inline c2"><div class="inline">2a<div>2<div class="inline c2">b<span class="b">b</span></div></div></div></div>
+    <div class="c3">3</div>
+    <div class="inline"><div class="inline c4">4</div></div>
+    <div><div class="inline c5">5a</div></div>
+    <div class="c5">5b</div>
+    <div class="inline c6"><div>6</div></div>
+    <div class="ib"><div class="inline c7"><div class="inline c2">7<span class="b">a</span></div></div></div>
+    <div class="inline c9"><div>8</div></div>
+    <div class="inline c9"><div class="inline">9<div class="inline c2">a</div></div></div>
+    <span class="c2 b">b</span>
+    <div class="inline c2">c</div>
+    <div class="inline c10"><div>10</div></div>
+  </div>
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-flex-002.html b/testing/web-platform/tests/css/css-display/display-contents-flex-002.html
new file mode 100644
index 0000000000..869ca00b72
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-flex-002.html
@@ -0,0 +1,25 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: CSS display: contents in flex layout</title>
+<!-- Imported from: https://bugzilla.mozilla.org/show_bug.cgi?id=907396 -->
+<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-flex-002-ref.html">
+<link rel="stylesheet" href="support/acid.css">
+<div class="flex c1">
+  0
+  <div class="contents c1">x</div>
+  <div class="contents c1"><div class="contents c2">y</div></div>
+  <div class="contents c1"><div class="contents c2"><div>1<span class="b">1</span></div></div></div>
+  <div class="contents c2"><div class="inline">2a<div>2<div class="contents c2">b<span class="b">b</span></div></div></div></div>
+  <div class="contents c3"><div class="inline">3</div></div>
+  <div class="inline"><div class="contents c4">4</div></div>
+  <div><div class="contents c5">5a</div></div>
+  <div class="c5">5b</div>
+  <div class="contents c6"><div>6</div></div>
+  <div class="ib"><div class="contents c7"><div class="contents c2">7<span class="b">a</span></div></div></div>
+  <div class="contents c9"><div>8</div></div>
+  <div class="contents c9"><div class="contents">9<div class="contents c2">a<span class="b">b</span>c</div></div></div>
+  <div class="contents c10"><div>10</div></div>
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-flex-003.html b/testing/web-platform/tests/css/css-display/display-contents-flex-003.html
new file mode 100644
index 0000000000..6425db9421
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-flex-003.html
@@ -0,0 +1,25 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: CSS display: contents in flex layout</title>
+<!-- Imported from: https://bugzilla.mozilla.org/show_bug.cgi?id=907396 -->
+<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-flex-002-ref.html">
+<link rel="stylesheet" href="support/acid.css">
+<div class="flex"><div class="contents c1">
+  0
+  <div class="contents c1">x</div>
+  <div class="contents c1"><div class="contents c2">y</div></div>
+  <div class="contents c1"><div class="contents c2"><div>1<span class="b">1</span></div></div></div>
+  <div class="contents c2"><div class="inline">2a<div>2<div class="contents c2">b<span class="b">b</span></div></div></div></div>
+  <div class="contents c3"><div class="inline">3</div></div>
+  <div><div class="contents c4">4</div></div>
+  <div><div class="contents c5">5a</div></div>
+  <div class="c5">5b</div>
+  <div class="contents c6"><div>6</div></div>
+  <div class="ib"><div class="contents c7"><div class="contents c2">7<span class="b">a</span></div></div></div>
+  <div class="contents c9"><div>8</div></div>
+  <div class="contents c9"><div class="contents">9<div class="contents c2">a<span class="b">b</span>c</div></div></div>
+  <div class="contents c10"><div>10</div></div>
+</div></div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-float-001.html b/testing/web-platform/tests/css/css-display/display-contents-float-001.html
new file mode 100644
index 0000000000..d51e7c1d4a
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-float-001.html
@@ -0,0 +1,15 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: display:contents works on floated elements</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-pass-no-red-ref.html">
+<style>
+  div {
+    display: contents;
+    float: right;
+    background: red;
+  }
+</style>
+<p>You should see the word PASS and no red below.</p>
+<div>P<span>A</span>S<span>S</span></div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-focusable-001.html b/testing/web-platform/tests/css/css-display/display-contents-focusable-001.html
new file mode 100644
index 0000000000..3f64718587
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-focusable-001.html
@@ -0,0 +1,45 @@
+<!DOCTYPE html>
+<title>CSS Test (Display): Elements with display:contents should be focusable</title>
+<link rel="author" title="L. David Baron" href="https://dbaron.org/">
+<link rel="author" title="Google" href="http://www.google.com/">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#box-generation">
+<link rel="help" href="https://github.com/w3c/csswg-drafts/issues/2632">
+<link rel="help" href="https://github.com/whatwg/html/issues/1837">
+<link rel="help" href="https://github.com/whatwg/html/pull/9425">
+<link rel="help" href="https://bugs.chromium.org/p/chromium/issues/detail?id=1366037">
+<!--
+
+  This requirement may not be crystal-clear from CSS specs, but
+  discussion in https://github.com/w3c/csswg-drafts/issues/2632
+  concluded it was correct and that no spec changes were needed.
+
+  https://github.com/whatwg/html/pull/9425 makes this clearer in the
+  HTML spec.
+
+-->
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<style>
+
+#test       { --test-var: test-not-focused; }
+#test:focus { --test-var: test-focused; }
+
+</style>
+
+<div id="test" style="display: contents" tabindex="1">Hello</div>
+
+<script>
+
+  test(
+    function() {
+      var e = document.getElementById("test");
+      var cs = getComputedStyle(e);
+      assert_not_equals(document.activeElement, e, "precondition");
+      assert_equals(cs.getPropertyValue("--test-var"), "test-not-focused", "precondition (style)");
+      e.focus();
+      assert_equals(document.activeElement, e, "e is now focused");
+      assert_equals(cs.getPropertyValue("--test-var"), "test-focused", "e is now focused (style)");
+    }, "element with display:contents is focusable");
+
+</script>
+
diff --git a/testing/web-platform/tests/css/css-display/display-contents-inline-001.html b/testing/web-platform/tests/css/css-display/display-contents-inline-001.html
new file mode 100644
index 0000000000..9527382e8b
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-inline-001.html
@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: display:contents in inline layout</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:rune@opera.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-pass-no-red-ref.html">
+<style>
+    #contents {
+        display: contents;
+        border: 10px solid red
+    }
+</style>
+<p>You should see the word PASS and no red below.</p>
+<span>
+    P<div id="contents">A<span>S</span></div>S
+</span>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-inline-flex-001-ref.html b/testing/web-platform/tests/css/css-display/display-contents-inline-flex-001-ref.html
new file mode 100644
index 0000000000..20ec437a51
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-inline-flex-001-ref.html
@@ -0,0 +1,31 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Reftest Reference</title>
+<!-- Imported from: https://bugzilla.mozilla.org/show_bug.cgi?id=907396 -->
+<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="stylesheet" href="support/acid.css">
+<div style="color: red" class="ref">
+<div class="iflex"><div class="contents c2">
+0
+</div></div>
+<div class="iflex"><div class="contents c2">
+0
+<div class="inline c1">1</div>
+2
+</div></div>
+<div class="iflex"><div class="contents c2">
+0<div class="inline c1">1</div>2
+</div></div>
+<div class="iflex c3">
+0<div class="inline c2"><div class="c1">1</div></div>2
+</div>
+<div class="iflex c3">
+<div class="inline c2">0</div><div class="inline c2"><div class="c1">1</div></div><div class="inline c2">2</div>
+</div>
+<div class="iflex c3">
+<div class="inline">0</div>
+<div class="inline"><div class="inline c1">1</div></div>
+<div class="inline">2</div>
+</div>
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-inline-flex-001.html b/testing/web-platform/tests/css/css-display/display-contents-inline-flex-001.html
new file mode 100644
index 0000000000..43b502731a
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-inline-flex-001.html
@@ -0,0 +1,39 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: CSS display: contents in inline-flex layout</title>
+<!-- Imported from: https://bugzilla.mozilla.org/show_bug.cgi?id=907396 -->
+<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-inline-flex-001-ref.html">
+<link rel="stylesheet" href="support/acid.css">
+<div style="color: red">
+  <div class="iflex"><div class="contents c2">
+  0
+  </div></div>
+  <div class="iflex"><div class="contents c2">
+  0
+  <div class="contents c1">1</div>
+  2
+  </div></div>
+  <div class="iflex"><div class="contents c2">
+  0
+  <div class="c1">1</div>
+  2
+  </div></div>
+  <div class="iflex c3">
+  0
+  <div class="contents c2"><div class="c1">1</div></div>
+  2
+  </div>
+  <div class="iflex c3">
+  <div class="contents c2">0</div>
+  <div class="contents c2"><div class="c1">1</div></div>
+  <div class="contents c2">2</div>
+  </div>
+  <div class="iflex c3">
+  <div class="inline">0</div>
+  <div class="contents"><div class="inline c1">1</div></div>
+  <div class="inline">2</div>
+  </div>
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-line-height-ref.html b/testing/web-platform/tests/css/css-display/display-contents-line-height-ref.html
new file mode 100644
index 0000000000..d06c63f09f
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-line-height-ref.html
@@ -0,0 +1,9 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Reftest Reference</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:futhark@chromium.org">
+<style>
+  span { font-size: 40px; }
+</style>
+<p>The two lines below should not overlap.</p>
+<span>Line 1</span><br><span>Line 2</span>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-line-height.html b/testing/web-platform/tests/css/css-display/display-contents-line-height.html
new file mode 100644
index 0000000000..31fd5a6d47
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-line-height.html
@@ -0,0 +1,14 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: display:contents font-size should affect line-height</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:futhark@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-line-height-ref.html">
+<style>
+  span {
+    display: contents;
+    font-size: 40px;
+  }
+</style>
+<p>The two lines below should not overlap.</p>
+<span>Line 1</span><br><span>Line 2</span>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-list-001-ref.html b/testing/web-platform/tests/css/css-display/display-contents-list-001-ref.html
new file mode 100644
index 0000000000..bc5dfbe5c8
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-list-001-ref.html
@@ -0,0 +1,26 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Reftest Reference</title>
+<!-- Imported from: https://bugzilla.mozilla.org/show_bug.cgi?id=907396 -->
+<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="stylesheet" href="support/acid.css">
+<div style="color: red" class="ref">
+  <ul><li class="c1"><div class="inline c2">
+  0
+  <div class="inline c1">x</div>
+  <div class="inline c1"><div class="inline c2">y</div></div>
+  <div class="inline c1"><div class="inline c2"><div>1<span>1</span></div></div></div>
+  <div class="inline c2"><div class="inline">2a<div>2<div class="inline c2">b<span class="b">b</span></div></div></div></div>
+  <div class="inline c3"><div class="inline">3</div></div>
+  <div class="inline"><div class="inline c4">4</div></div>
+  <div><div class="inline c5">5a</div></div>
+  <div class="c5">5b</div>
+  <div class="inline c6"><div>6</div></div>
+  <div class="ib"><div class="inline c7"><div class="inline c2">7<span class="b">a</span></div></div></div>
+  <div class="inline c9"><div>8</div></div>
+  <div class="inline c9"><div class="inline">9<div class="inline c2">a<span class="b">b</span>c</div></div></div>
+  <div class="inline c10"><div>10</div></div>
+  </div></li>
+  </ul>
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-list-001.html b/testing/web-platform/tests/css/css-display/display-contents-list-001.html
new file mode 100644
index 0000000000..7b1fd44cae
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-list-001.html
@@ -0,0 +1,27 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: CSS display: contents in list layout</title>
+<!-- Imported from: https://bugzilla.mozilla.org/show_bug.cgi?id=907396 -->
+<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-list-001-ref.html">
+<link rel="stylesheet" href="support/acid.css">
+<div style="color: red">
+  <ul><li class="c1"><div class="contents c2">
+  0
+  <div class="contents c1">x</div>
+  <div class="contents c1"><div class="contents c2">y</div></div>
+  <div class="contents c1"><div class="contents c2"><div>1<span class="b">1</span></div></div></div>
+  <div class="contents c2"><div class="inline">2a<div>2<div class="contents c2">b<span class="b">b</span></div></div></div></div>
+  <div class="contents c3"><div class="inline">3</div></div>
+  <div class="inline"><div class="contents c4">4</div></div>
+  <div><div class="contents c5">5a</div></div>
+  <div class="c5">5b</div>
+  <div class="contents c6"><div>6</div></div>
+  <div class="ib"><div class="contents c7"><div class="contents c2">7<span class="b">a</span></div></div></div>
+  <div class="contents c9"><div>8</div></div>
+  <div class="contents c9"><div class="contents">9<div class="contents c2">a<span class="b">b</span>c</div></div></div>
+  <div class="contents c10"><div>10</div></div>
+  </div></li></ul>
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-multicol-001-ref.html b/testing/web-platform/tests/css/css-display/display-contents-multicol-001-ref.html
new file mode 100644
index 0000000000..0d371b3442
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-multicol-001-ref.html
@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Reftest Reference</title>
+<!-- Imported from: https://bugzilla.mozilla.org/show_bug.cgi?id=907396 -->
+<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="stylesheet" href="support/acid.css">
+<div style="color: red" class="ref">
+  <div class="columns">
+  <div class="contents c1"><div class="contents c2"><div>1<span>1</span></div></div></div>
+  <div class="contents c2"><div>2</div></div>
+  <div class="contents c3"><div>3</div></div>
+  </div>
+
+  <div class="columns">
+  <div class="contents c1"><div class="contents c2"><div>1<span>1</span></div></div></div>
+  <div class="contents c2"><div>2</div></div>
+  <div class="contents c3"><div>3</div></div>
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-multicol-001.html b/testing/web-platform/tests/css/css-display/display-contents-multicol-001.html
new file mode 100644
index 0000000000..2213fdc684
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-multicol-001.html
@@ -0,0 +1,24 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: CSS display:contents in multicolumn layout</title>
+<!-- Imported from: https://bugzilla.mozilla.org/show_bug.cgi?id=907396 -->
+<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-multicol-001-ref.html">
+<link rel="stylesheet" href="support/acid.css">
+<div style="color: red">
+  <div class="columns">
+  <div class="contents c1"><div class="contents c2"><div>1<span class="b">1</span></div></div></div>
+  <div class="contents c2"><div>2</div></div>
+  <div class="contents c3"><div>3</div></div>
+  </div>
+
+  <div class="columns">
+  <div class="columns contents">
+  <div class="contents c1"><div class="contents c2"><div>1<span class="b">1</span></div></div></div>
+  <div class="contents c2"><div>2</div></div>
+  <div class="contents c3"><div>3</div></div>
+  </div>
+  </div>
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-oof-001.html b/testing/web-platform/tests/css/css-display/display-contents-oof-001.html
new file mode 100644
index 0000000000..03509bf9ef
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-oof-001.html
@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: display:contents works on out-of-flow positioned elements</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-pass-no-red-ref.html">
+<style>
+  div {
+    display: contents;
+    position: absolute;
+    right: 0;
+    background: red;
+  }
+</style>
+<p>You should see the word PASS and no red below.</p>
+<div>P<span>A</span>S<span>S</span></div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-oof-002.html b/testing/web-platform/tests/css/css-display/display-contents-oof-002.html
new file mode 100644
index 0000000000..8df8251a67
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-oof-002.html
@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: display:contents works on out-of-flow positioned elements</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-pass-no-red-ref.html">
+<style>
+  div {
+    display: contents;
+    position: fixed;
+    right: 0;
+    background: red;
+  }
+</style>
+<p>You should see the word PASS and no red below.</p>
+<div>P<span>A</span>S<span>S</span></div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-parsing-001.html b/testing/web-platform/tests/css/css-display/display-contents-parsing-001.html
new file mode 100644
index 0000000000..085d12b103
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-parsing-001.html
@@ -0,0 +1,43 @@
+<!doctype html>
+<meta charset="utf-8">
+<title>Tests that the 'contents' value for the 'display' property is correctly parsed</title>
+<link rel="help" href="https://drafts.csswg.org/css-display/#box-generation">
+<link rel="author" href="mailto:ecobos@igalia.com" title="Emilio Cobos Álvarez">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<style>
+  .contents {
+    display: contents;
+  }
+
+  .contents-then-block {
+    display: contents;
+    display: block;
+  }
+
+  .content {
+    display: content;
+  }
+</style>
+<div class="contents" id="contentsElement"></div>
+<div class="content" id="bogusContentsElement"></div>
+<div class="contents-then-block" id="contentsThenBlockElement"></div>
+<script>
+test(function() {
+  var contentsElement = document.getElementById("contentsElement");
+  var bogusContentsElement = document.getElementById("bogusContentsElement");
+  var contentsThenBlockElement = document.getElementById("contentsThenBlockElement");
+
+  assert_equals(getComputedStyle(contentsElement).getPropertyValue("display"), "contents");
+  assert_equals(getComputedStyle(bogusContentsElement).getPropertyValue("display"), "block");
+  assert_equals(getComputedStyle(contentsThenBlockElement).getPropertyValue("display"), "block");
+
+  var element = document.createElement("div");
+  document.body.appendChild(element);
+  assert_equals(getComputedStyle(element).getPropertyValue("display"), "block");
+  element.style.display = "contents";
+  assert_equals(getComputedStyle(element).getPropertyValue("display"), "contents");
+  element.style.display = "block";
+  assert_equals(getComputedStyle(element).getPropertyValue("display"), "block");
+});
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-pass-green-no-red-ref.html b/testing/web-platform/tests/css/css-display/display-contents-pass-green-no-red-ref.html
new file mode 100644
index 0000000000..9e7349cacd
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-pass-green-no-red-ref.html
@@ -0,0 +1,6 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Reftest Reference</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:rune@opera.com">
+<p>You should see the word PASS in green and no red below.</p>
+<div style="color:green"><span>P</span>ASS</div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-pass-no-red-ref.html b/testing/web-platform/tests/css/css-display/display-contents-pass-no-red-ref.html
new file mode 100644
index 0000000000..3e445d4b43
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-pass-no-red-ref.html
@@ -0,0 +1,6 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Reftest Reference</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:rune@opera.com">
+<p>You should see the word PASS and no red below.</p>
+<div>P<span>A</span>S<span>S</span></div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-pass-ref.html b/testing/web-platform/tests/css/css-display/display-contents-pass-ref.html
new file mode 100644
index 0000000000..82321b9c07
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-pass-ref.html
@@ -0,0 +1,10 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Reftest Reference</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:rune@opera.com">
+<style>
+/* Disable kerning because kerning may differ for different node tree. */
+html { font-kerning: none; font-feature-settings: "kern" off; }
+</style>
+<p>You should see the word PASS below.</p>
+PASS
diff --git a/testing/web-platform/tests/css/css-display/display-contents-root-background-ref.html b/testing/web-platform/tests/css/css-display/display-contents-root-background-ref.html
new file mode 100644
index 0000000000..720ef20d83
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-root-background-ref.html
@@ -0,0 +1,4 @@
+<!doctype html>
+<html style="background:green">
+<title>CSS Test Reference</title>
+<p>Pass if the background is green.</p>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-root-background.html b/testing/web-platform/tests/css/css-display/display-contents-root-background.html
new file mode 100644
index 0000000000..6770266f51
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-root-background.html
@@ -0,0 +1,12 @@
+<!doctype html>
+<title>CSS Test: display:contents on root element blockified with rendered background.</title>
+<link rel="help" href="https://drafts.csswg.org/css-display/#the-display-properties">
+<link rel="help" href="https://drafts.csswg.org/css-display/#transformations">
+<link rel="match" href="display-contents-root-background-ref.html">
+<style>
+  :root {
+    display: contents;
+    background-image: url(../support/1x1-green.png);
+  }
+</style>
+<p>Pass if the background is green.</p>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-shadow-dom-1-ref.html b/testing/web-platform/tests/css/css-display/display-contents-shadow-dom-1-ref.html
new file mode 100644
index 0000000000..324cfc3cec
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-shadow-dom-1-ref.html
@@ -0,0 +1,48 @@
+<!DOCTYPE html>
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<html>
+  <head>
+  <title>Reference: CSS display:contents; in Shadow DOM</title>
+  <link rel="author" title="Mats Palmgren" href="https://bugzilla.mozilla.org/show_bug.cgi?id=907396">
+<style>
+html,body {
+  color:black; background-color:white; font:20px/1 monospace; padding:0; margin:0;
+}
+
+span { color:blue; }
+</style>
+  </head>
+  <body>
+    <div>X 1 c</div>
+    <div>a 2 c</div>
+    <div>a 3 Y</div>
+    <div>X 4 Y</div>
+    <div>a 5 Y</div>
+    <div>X <span>6</span> c</div>
+    <div>a <span>7</span> c</div>
+    <div>a <span>8</span> Y</div>
+    <div>X <span>9</span> Y</div>
+    <div>a <span>A</span> Y</div>
+    <div>a <span>1 2</span> B</div>
+    <div>A <span>a 1 2 c</span> B</div>
+    <div>A <span>a 1 a 2 ca 3 c</span> B</div>
+    <div>A <span>a 1 c a 2 c</span> B</div>
+    <div>X <span>a 1 c a 2 c</span> B</div>
+    <div><span>1a 2 c</span></div>
+    <div><span>a 1 c2</span></div>
+    <div>A<span>b</span>c</div>
+    <div>A<span>b</span>c</div>
+    <div><span>b c</span>d</div>
+    <div><span>a </span>b</div>
+    <div><b>One</b><i>Two</i></div>
+    <div><b>One</b><i>Two</i></div>
+    <div><b>One</b><i>Two</i></div>
+    <div><b>One</b><i>Two</i></div>
+    <b style="color:blue">One</b><i style="color:blue">Two</i>Three
+    <div></div>
+    <b style="color:green">V</b>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-shadow-dom-1.html b/testing/web-platform/tests/css/css-display/display-contents-shadow-dom-1.html
new file mode 100644
index 0000000000..45dd6d9b77
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-shadow-dom-1.html
@@ -0,0 +1,221 @@
+<!DOCTYPE html>
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<html class="reftest-wait" lang="en-US">
+  <head>
+  <meta charset="utf-8">
+  <title>CSS Test: CSS display:contents; in Shadow DOM</title>
+  <link rel="author" title="Mats Palmgren" href="https://bugzilla.mozilla.org/show_bug.cgi?id=907396">
+  <link rel="help" href="https://drafts.csswg.org/css-display/">
+  <link rel="match" href="display-contents-shadow-dom-1-ref.html">
+<style>
+html,body {
+  color:black; background-color:white; font:20px/1 monospace; padding:0; margin:0;
+}
+.before::before, ::slotted(.before)::before {content: "a ";}
+.after::after, ::slotted(.after)::after {content: " c";}
+div.before::before {content: "X ";}
+div.after::after {content: " Y";}
+.b, .c, ::slotted(.b), ::slotted(.c) { display:contents; }
+</style>
+  </head>
+  <body>
+    <div id="host1" class="before"></div>
+    <span id="host2"></span>
+    <div id="host3" class="after"></div>
+    <div id="host4" class="before after"></div>
+    <div id="host5" class="after"></div>
+    <div id="host6" class="before"></div>
+    <div id="host7"></div>
+    <div id="host8" class="after"></div>
+    <div id="host9" class="before after"></div>
+    <div id="hostA" class="after"></div>
+    <div id="hostB"></div>
+    <div id="hostC"></div>
+    <div id="hostD"></div>
+    <div id="hostE"></div>
+    <div id="hostF" class="before"></div>
+    <div id="hostG"></div>
+    <span id="hostH"></span>
+    <div id="hostI"></div>
+    <div id="hostJ"></div>
+    <span id="hostK"></span>
+    <div id="hostL"></div>
+    <div id="hostM"><i slot=i>Two</i><b slot=b>One</b></div>
+    <div id="hostN"><i slot=i class="c">Two</i><b slot=b>One</b></div>
+    <div id="hostO"><i slot=i>Two</i><b slot=b class="c">One</b></div>
+    <div id="hostP"><i slot=i class="c">Two</i><b slot=b class="c">One</b></div>
+    <div id="hostQ" class="c" style="color:blue"><i slot=i class="c">Two</i><b slot=b class="c">One</b></div>Three
+    <div id="hostS" class="c"><span class="c">S</span></div>
+    <div id="hostT" class="c">T</div>
+    <div id="hostU"><span slot="c">U</span></div>
+    <div id="hostV" class="c" style="color:red"><b slot="b" class="c" style="color:inherit">V</b></div>
+
+   <script>
+      function shadow(id) {
+        return document.getElementById(id).attachShadow({mode:"open"});
+      }
+      function span(s) {
+        var e = document.createElement("span");
+        var t = document.createTextNode(s);
+        e.appendChild(t);
+        return e;
+      }
+      function text(s) {
+        return document.createTextNode(s);
+      }
+      function contents(n, slotName) {
+        var e = document.createElement("z");
+        e.style.display = "contents";
+        e.style.color = "blue";
+        if (n) e.appendChild(n);
+        if (slotName) e.setAttribute("slot", slotName);
+        return e;
+      }
+
+      function run() {
+        document.body.offsetHeight;
+
+        shadow("host1").innerHTML = '<slot style="display:inline"></slot> c';
+        shadow("host2").innerHTML = 'a <slot style="display:contents"></slot> c';
+        shadow("host3").innerHTML = 'a <slot style="display:contents"></slot>';
+        shadow("host4").innerHTML = '<slot style="display:contents"></slot>';
+        shadow("host5").innerHTML = 'a <slot style="display:contents"></slot>';
+        shadow("host6").innerHTML = '<z style="color:blue; display:contents"><slot style="display:inline"></slot></z> c';
+        shadow("host7").innerHTML = 'a <slot style="display:contents"></slot> c';
+        shadow("host8").innerHTML = 'a <z style="color:blue; display:contents"><slot style="display:contents"></z></slot>';
+        shadow("host9").innerHTML = '<slot style="display:contents"></slot>';
+        shadow("hostA").innerHTML = 'a <slot style="display:contents"></slot>';
+        shadow("hostB").innerHTML = 'a <slot name="c" style="display:contents"></slot> <slot name="b" style="display:contents"></slot> B';
+        shadow("hostC").innerHTML = 'A <slot name="c" style="display:contents"></slot> <slot name="b" style="display:contents"></slot> B';
+        shadow("hostD").innerHTML = 'A <slot name="c" style="display:contents"></slot> <slot name="b" style="display:contents"></slot> B <slot name="b"></slot>';
+        shadow("hostE").innerHTML = 'A <slot name="c" style="display:contents"></slot> <slot name="b" style="display:contents"></slot> B';
+        shadow("hostF").innerHTML = '<slot name="c" style="display:contents"></slot> <slot name="b" style="display:contents"></slot> B';
+        shadow("hostG").innerHTML = '<slot name="b" style="display:contents"></slot>';
+        shadow("hostH").innerHTML = '<slot name="b" style="display:contents"></slot>';
+        shadow("hostI").innerHTML = 'A<slot name="b" style="display:contents"></slot>';
+        shadow("hostJ").innerHTML = 'A<slot name="b" style="display:contents"></slot>';
+        shadow("hostK").innerHTML = '<slot name="b" style="display:contents"></slot>';
+        shadow("hostL").innerHTML = '<slot name="b" style="display:contents"></slot>';
+        shadow("hostM").innerHTML = '<slot name="b" style="display:contents"></slot><slot name="i" style="display:inline"></slot>';
+        shadow("hostN").innerHTML = '<slot name="b" style="display:contents"></slot><slot name="i" style="display:inline"></slot>';
+        shadow("hostO").innerHTML = '<slot name="b" style="display:contents"></slot><slot name="i" style="display:inline"></slot>';
+        shadow("hostP").innerHTML = '<slot name="b" style="display:contents"></slot><slot name="i" style="display:inline"></slot>';
+        shadow("hostQ").innerHTML = '<slot name="b" style="display:contents"></slot><slot name="i" style="display:inline"></slot>';
+      }
+
+      function tweak() {
+        document.body.offsetHeight;
+
+        host1.appendChild(span("1"));
+        host2.appendChild(text("2"));
+        host3.appendChild(span("3"));
+        host4.appendChild(text("4"));
+
+        var e = span("5");
+        e.style.display = "contents";
+        host5.appendChild(e);
+
+        host6.appendChild(span("6"));
+        host7.appendChild(contents(text("7")));
+        host8.appendChild(contents(span("8")));
+        host9.appendChild(contents(text("9")));
+
+        var e = contents(span("A"));
+        hostA.appendChild(e);
+
+        var e = contents(text("2"), "b");
+        hostB.appendChild(e);
+        var e = contents(text("1"), "c");
+        hostB.appendChild(e);
+
+        var e = contents(text("2"), "b");
+        e.className = "after";
+        hostC.appendChild(e);
+        var e = contents(text("1"), "c");
+        e.className = "before";
+        hostC.appendChild(e);
+
+        var e = contents(text("2"), "b");
+        e.className = "before after";
+        hostD.appendChild(e);
+        var e = contents(text(" 3"), "b");
+        e.className = "before after";
+        hostD.appendChild(e);
+        var e = contents(text("1"), "c");
+        e.className = "before";
+        hostD.appendChild(e);
+
+        var e = contents(contents(text("2")), "b");
+        e.className = "before after";
+        hostE.appendChild(e);
+        var e2 = contents(text("1"), "c");
+        e2.className = "before after";
+        hostE.insertBefore(e2, e);
+
+        var e = contents(text("2"), "b");
+        e.className = "before after";
+        hostF.appendChild(e);
+        var e2 = contents(text("1"), "c");
+        e2.className = "before after";
+        hostF.insertBefore(e2, e);
+
+        var e = contents(contents(text("1")), "b");
+        hostG.appendChild(e);
+        var e = contents(text("2"), "b");
+        e.className = "before after";
+        hostG.appendChild(e);
+
+        var e = contents(contents(text("2")), "b");
+        hostH.appendChild(e);
+        var e2 = contents(text("1"), "b");
+        e2.className = "before after";
+        hostH.insertBefore(e2, e);
+
+        var e = contents(text("b"), "b");
+        hostI.appendChild(e);
+        var e = span("c");
+        e.setAttribute("slot", "b");
+        hostI.appendChild(e);
+
+        var e = contents(contents(text("b")), "b");
+        hostJ.appendChild(e);
+        var e = span("c");
+        e.setAttribute("slot", "b");
+        hostJ.appendChild(e);
+
+        var inner = span("b");
+        inner.className = "after";
+        var e = contents(contents(inner), "b");
+        hostK.appendChild(e);
+        var e = span("d");
+        e.setAttribute("slot", "b");
+        hostK.appendChild(e);
+
+        var inner = contents(null);
+        inner.className = "before";
+        var e = contents(inner, "b");
+        hostL.appendChild(e);
+        var e = span("b");
+        e.setAttribute("slot", "b");
+        hostL.appendChild(e);
+
+        document.body.offsetHeight;
+        setTimeout(function() {
+            shadow("hostS");
+            shadow("hostT");
+            shadow("hostU");
+            shadow("hostV").innerHTML = '<z style="color:green"><slot name="b"></slot></z>';
+
+            document.body.offsetHeight;
+            document.documentElement.removeAttribute("class");
+          },0);
+      }
+
+      run();
+      setTimeout(tweak, 0);
+    </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-shadow-host-whitespace.html b/testing/web-platform/tests/css/css-display/display-contents-shadow-host-whitespace.html
new file mode 100644
index 0000000000..84b04dba10
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-shadow-host-whitespace.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Whitespace across display:contents shadow host</title>
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="help" href="https://drafts.csswg.org/css-text-3/#white-space-rules">
+<link rel="match" href="../reference/pass_if_two_words.html">
+<p>There should be a space between "two" and "words" below.</p>
+<div id="host" style="display:contents"></div> <span>words</span>
+<script>
+  host.attachShadow({mode:"open"}).innerHTML = "two";
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-sharing-001-ref.html b/testing/web-platform/tests/css/css-display/display-contents-sharing-001-ref.html
new file mode 100644
index 0000000000..a047f326fe
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-sharing-001-ref.html
@@ -0,0 +1,10 @@
+<!doctype html>
+<meta charset="utf-8">
+<title style="display: none">CSS Test Reference</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
+<style>
+  * { display: contents }
+</style>
+<whatever>
+  PASS
+</whatever>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-sharing-001.html b/testing/web-platform/tests/css/css-display/display-contents-sharing-001.html
new file mode 100644
index 0000000000..3ecb8eb2b1
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-sharing-001.html
@@ -0,0 +1,14 @@
+<!doctype html>
+<meta charset="utf-8">
+<title style="display: none">CSS Test: display:contents style sharing.</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
+<link rel="match" href="display-contents-sharing-001-ref.html">
+<link rel="help" href="https://drafts.csswg.org/css-display/#unbox-html">
+<link rel="help" href="https://bugzil.la/1469076">
+<style>
+  * { display: contents }
+</style>
+<br>
+<whatever>
+  PASS
+</whatever>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-slot-attach-whitespace.html b/testing/web-platform/tests/css/css-display/display-contents-slot-attach-whitespace.html
new file mode 100644
index 0000000000..c29b5ba634
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-slot-attach-whitespace.html
@@ -0,0 +1,11 @@
+<!doctype html>
+<title>Attaching shadow slot with assigned whitespace separated inline elements</title>
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="help" href="https://drafts.csswg.org/css-text-3/#white-space-rules">
+<link rel="match" href="../reference/pass_if_two_words.html">
+<p>There should be a space between "two" and "words" below.</p>
+<div id="host"><span>two</span> <span>words</span></div>
+<script>
+  host.offsetTop;
+  host.attachShadow({mode:"open"}).innerHTML = "<slot></slot>";
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-state-change-001-ref.html b/testing/web-platform/tests/css/css-display/display-contents-state-change-001-ref.html
new file mode 100644
index 0000000000..244572a685
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-state-change-001-ref.html
@@ -0,0 +1,12 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS test reference</title>
+<link rel="author" name="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<style>
+div {
+  color: green;
+}
+</style>
+<div>
+  This text should be green, there should be no red border at any time.
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-state-change-001.html b/testing/web-platform/tests/css/css-display/display-contents-state-change-001.html
new file mode 100644
index 0000000000..3923041e0d
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-state-change-001.html
@@ -0,0 +1,30 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS display: State changes are handled correctly for display: contents children</title>
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="author" name="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="match" href="display-contents-state-change-001-ref.html">
+<style>
+:focus-within .contents {
+  color: green;
+}
+.contents {
+  display: contents;
+  border: 10px solid red;
+  color: red;
+}
+input {
+  position: absolute;
+  left: -9999px;
+  top: -9999px;
+}
+</style>
+<div>
+  <input type="text">
+  <div class="contents">This text should be green, there should be no red border at any time.</div>
+</div>
+<script>
+onload = function() {
+  document.querySelector('input').focus();
+}
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-suppression-dynamic-001-ref.html b/testing/web-platform/tests/css/css-display/display-contents-suppression-dynamic-001-ref.html
new file mode 100644
index 0000000000..07a5663748
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-suppression-dynamic-001-ref.html
@@ -0,0 +1,5 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test Reference</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
+<p>Test passes if you see nothing below.</p>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-suppression-dynamic-001.html b/testing/web-platform/tests/css/css-display/display-contents-suppression-dynamic-001.html
new file mode 100644
index 0000000000..5007e1f57d
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-suppression-dynamic-001.html
@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: display: contents unboxing works in presence of dynamic changes to the tree.</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#unbox">
+<link rel="match" href="display-contents-suppression-dynamic-001-ref.html">
+<p>Test passes if you see nothing below.</p>
+<textarea style="display: contents">
+  FAIL
+</textarea>
+<script>
+  let textarea = document.querySelector("textarea");
+  textarea.offsetTop;
+  textarea.appendChild(document.createTextNode("FAIL"));
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-svg-anchor-child.html b/testing/web-platform/tests/css/css-display/display-contents-svg-anchor-child.html
new file mode 100644
index 0000000000..d0119d7fff
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-svg-anchor-child.html
@@ -0,0 +1,20 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: display:contents on SVG anchor child</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:futhark@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-display/#unbox-svg">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<svg>
+  <a>
+    <tspan style="display:contents;color:green">Text</tspan>
+  </a>
+  <text>
+    <a>
+      <tspan style="display:contents;color:green">Text</tspan>
+    </a>
+  </text>
+</svg>
+<script>
+  test(() => {}, "Loading this page should not cause a crash.");
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-svg-elements-ref.html b/testing/web-platform/tests/css/css-display/display-contents-svg-elements-ref.html
new file mode 100644
index 0000000000..b691e0e80e
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-svg-elements-ref.html
@@ -0,0 +1,13 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Reftest Reference</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:futhark@chromium.org">
+<p>You should see the word PASS below.</p>
+<div style="font: 16px monospace">
+  <svg>
+    <text x="0" y="20">P</text>
+    <text x="10" y="20">A</text>
+    <text x="20" y="20">S</text>
+    <text x="30" y="20">S</text>
+  </svg>
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-svg-elements.html b/testing/web-platform/tests/css/css-display/display-contents-svg-elements.html
new file mode 100644
index 0000000000..7ccc92f720
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-svg-elements.html
@@ -0,0 +1,22 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: display:contents and SVG elements</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:futhark@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-display/#unbox-svg">
+<link rel="match" href="display-contents-svg-elements-ref.html">
+<p>You should see the word PASS below.</p>
+<div style="font: 16px monospace">
+  <svg>
+    <defs><text x="20" y="20" id="S">S</text></defs>
+    <text y="40" style="display:contents">FAIL</text>
+    <svg style="display:contents;opacity:0">
+      <text x="0" y="20">P</text>
+    </svg>
+    <g style="display:contents;opacity:0">
+      <text x="10" y="20"><tspan dx="2000" style="display:contents;opacity:0">A</tspan></text>
+    </g>
+    <use xlink:href="#S" style="display:contents;opacity:0"></use>
+    <text x="30" y="20">S</text>
+  </svg>
+  <svg style="display:contents"><text y="40">FAIL</text></svg>
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-svg-switch-child.html b/testing/web-platform/tests/css/css-display/display-contents-svg-switch-child.html
new file mode 100644
index 0000000000..7befdb415b
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-svg-switch-child.html
@@ -0,0 +1,15 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: display:contents on SVG switch child</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:futhark@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-display/#unbox-svg">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<svg>
+  <switch>
+    <tspan style="display:contents;color:green">Text</tspan>
+  </switch>
+</svg>
+<script>
+  test(() => {}, "Loading this page should not cause a crash.");
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-table-001-ref.html b/testing/web-platform/tests/css/css-display/display-contents-table-001-ref.html
new file mode 100644
index 0000000000..597f153724
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-table-001-ref.html
@@ -0,0 +1,21 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Reftest Reference</title>
+<!-- Imported from: https://bugzilla.mozilla.org/show_bug.cgi?id=907396 -->
+<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="stylesheet" href="support/acid.css">
+<div style="color: red" class="ref">
+  <div class="caption c2">1<span>1</span></div>
+  <div class="row c2">2a<div class="cell">2<div class="inline c2">b<span class="b">b</span></div></div></div>
+  <div class="cell c3">3</div>
+  <div class="rowg c4">4</div>
+  <div class="cell c5">5a</div>
+  <div class="cell c5">5b</div>
+  <div class="head c6">6</div>
+  <div class="cell c7"><div class="inline c2">7<span class="b">a</span></div></div>
+  <div class="cell c8">7b</div>
+  <div class="foot c9">8</div>
+  <div class="foot c9">9<div class="inline c2">a<span class="b">b</span>c</div></div>
+  <div class="cell c10">10</div>
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-table-001.html b/testing/web-platform/tests/css/css-display/display-contents-table-001.html
new file mode 100644
index 0000000000..d3c37fe361
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-table-001.html
@@ -0,0 +1,23 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: CSS display:contents in table layout</title>
+<!-- Imported from: https://bugzilla.mozilla.org/show_bug.cgi?id=907396 -->
+<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-table-001-ref.html">
+<link rel="stylesheet" href="support/acid.css">
+<div style="color: red">
+  <div class="contents c1"><div class="contents c2"><div class="caption">1<span class="b">1</span></div></div></div>
+  <div class="contents c2"><div class="row">2a<div class="cell">2<div class="contents c2">b<span class="b">b</span></div></div></div></div>
+  <div class="contents c3"><div class="cell">3</div></div>
+  <div class="contents c4"><div class="rowg">4</div></div>
+  <div class="contents c5"><div class="cell">5a</div></div>
+  <div class="cell c5">5b</div>
+  <div class="contents c6"><div class="head">6</div></div>
+  <div class="contents c7"><div class="cell"><div class="contents c2">7<span class="b">a</span></div></div></div>
+  <div class="contents c8"><div class="cell">7b</div></div>
+  <div class="contents c9"><div class="foot">8</div></div>
+  <div class="contents c9"><div class="foot">9<div class="contents c2">a<span class="b">b</span>c</div></div></div>
+  <div class="contents c10"><div class="cell">10</div></div>
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-table-002-ref.html b/testing/web-platform/tests/css/css-display/display-contents-table-002-ref.html
new file mode 100644
index 0000000000..1ea41e1694
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-table-002-ref.html
@@ -0,0 +1,24 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Reftest Reference</title>
+<!-- Imported from: https://bugzilla.mozilla.org/show_bug.cgi?id=907396 -->
+<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="stylesheet" href="support/acid.css">
+<div style="color: red" class="ref">
+  <div class="table" style="float:right">
+    <div class="caption c2">1<span>1</span></div>
+    <div class="row c2">2a<div class="cell">2<div class="inline c2">b<span class="b">b</span></div></div></div>
+    <div class="cell c3" style="border:none">3</div>
+    <div class="rowg c4">4</div>
+    <div class="cell c5" style="border:none">5a</div>
+    <div class="cell c5">5b</div>
+    <div class="head c6">6</div>
+    <div class="cell c7" style="border:none"><div class="inline c2">7<span class="b">a</span></div></div>
+    <div class="cell c8" style="border:none">7b</div>
+    <div class="foot c9" style="border:none">8</div>
+    <div class="foot c9">9<div class="inline c2">a<span class="b">b</span>c</div></div>
+    <div class="cell c10" style="border:none">10</div>
+  </div>
+</div>
+
diff --git a/testing/web-platform/tests/css/css-display/display-contents-table-002.html b/testing/web-platform/tests/css/css-display/display-contents-table-002.html
new file mode 100644
index 0000000000..2a30a1b8b1
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-table-002.html
@@ -0,0 +1,25 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: CSS display:contents in table layout</title>
+<!-- Imported from: https://bugzilla.mozilla.org/show_bug.cgi?id=907396 -->
+<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-table-002-ref.html">
+<link rel="stylesheet" href="support/acid.css">
+<div style="color: red">
+  <div class="table" style="float:right">
+    <div class="contents c1"><div class="contents c2"><div class="caption">1<span class="b">1</span></div></div></div>
+    <div class="contents c2"><div class="row">2a<div class="cell">2<div class="contents c2">b<span class="b">b</span></div></div></div></div>
+    <div class="contents c3"><div class="cell">3</div></div>
+    <div class="contents c4"><div class="rowg">4</div></div>
+    <div class="contents c5"><div class="cell">5a</div></div>
+    <div class="cell c5">5b</div>
+    <div class="contents c6"><div class="head">6</div></div>
+    <div class="contents c7"><div class="cell"><div class="contents c2">7<span class="b">a</span></div></div></div>
+    <div class="contents c8"><div class="cell">7b</div></div>
+    <div class="contents c9"><div class="foot">8</div></div>
+    <div class="contents c9"><div class="foot">9<div class="contents c2">a<span class="b">b</span>c</div></div></div>
+    <div class="contents c10"><div class="cell">10</div></div>
+  </div>
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-td-001.html b/testing/web-platform/tests/css/css-display/display-contents-td-001.html
new file mode 100644
index 0000000000..5585024a49
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-td-001.html
@@ -0,0 +1,20 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: Children of multiple td elements with display:contents wrapped in single anonymous table cell</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:rune@opera.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-pass-ref.html">
+<style>
+    /* Disable kerning because kerning may differ for different node tree. */
+    html { font-kerning: none; font-feature-settings: "kern" off; }
+    td {
+        display: contents;
+        padding-right: 3em
+    }
+</style>
+<p>You should see the word PASS below.</p>
+<table cellpadding="0" cellspacing="0">
+    <tr>
+        <td>P</td><td>A</td><td>S</td><td>S</td>
+    </tr>
+</table>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-text-inherit-002.html b/testing/web-platform/tests/css/css-display/display-contents-text-inherit-002.html
new file mode 100644
index 0000000000..51bf96846c
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-text-inherit-002.html
@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: Apply white-space property of display:contents element to inline children</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:futhark@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-text-inherit-ref.html">
+<p>The words "Two" and "lines" should not be on the same line.</p>
+<div id="div" style="background-color:red">
+  <span style="display:contents;white-space:pre-line">Two
+    lines
+  </span>
+</div>
+<script>
+  document.body.offsetTop;
+  div.style.backgroundColor = "transparent";
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-text-inherit-ref.html b/testing/web-platform/tests/css/css-display/display-contents-text-inherit-ref.html
new file mode 100644
index 0000000000..163efd401c
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-text-inherit-ref.html
@@ -0,0 +1,7 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Reftest Reference</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:futhark@chromium.org">
+<p>The words "Two" and "lines" should not be on the same line.</p>
+Two<br>
+lines
diff --git a/testing/web-platform/tests/css/css-display/display-contents-text-inherit.html b/testing/web-platform/tests/css/css-display/display-contents-text-inherit.html
new file mode 100644
index 0000000000..b7e769cd69
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-text-inherit.html
@@ -0,0 +1,15 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: Apply display:contents text properties to text children</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:futhark@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-text-inherit-ref.html">
+<style>
+  div {
+    display: contents;
+    white-space: pre;
+  }
+</style>
+<p>The words "Two" and "lines" should not be on the same line.</p>
+<div>Two
+lines</div>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-text-only-001-ref.html b/testing/web-platform/tests/css/css-display/display-contents-text-only-001-ref.html
new file mode 100644
index 0000000000..7d055f2cec
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-text-only-001-ref.html
@@ -0,0 +1,9 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Reftest Reference</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<style>
+  html, body { margin: 0; padding: 0; }
+</style>
+<p>Test passes if you see the word "PASS" below</p>
+PASS
diff --git a/testing/web-platform/tests/css/css-display/display-contents-text-only-001.html b/testing/web-platform/tests/css/css-display/display-contents-text-only-001.html
new file mode 100644
index 0000000000..0f4ebf7aae
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-text-only-001.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: Only text on a display: contents subtree</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-text-only-001-ref.html">
+<style>
+  body { display: contents; }
+</style>
+<p>Test passes if you see the word "PASS" below</p>
+PASS
diff --git a/testing/web-platform/tests/css/css-display/display-contents-tr-001-ref.html b/testing/web-platform/tests/css/css-display/display-contents-tr-001-ref.html
new file mode 100644
index 0000000000..9d57f1a802
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-tr-001-ref.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Reftest Reference</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:rune@opera.com">
+<p>You should see the word PASS below.</p>
+<table cellpadding="0" cellspacing="0">
+  <tr>
+    <td>P<span>A</span></td>
+    <td>S<span>S</span></td>
+  </tr>
+</table>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-tr-001.html b/testing/web-platform/tests/css/css-display/display-contents-tr-001.html
new file mode 100644
index 0000000000..f0f6894c95
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-tr-001.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: td elements wrapped in single anonymous table-row with display:contents tr</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:rune@opera.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="match" href="display-contents-tr-001-ref.html">
+<style>
+    tr { display: contents }
+</style>
+<p>You should see the word PASS below.</p>
+<table cellpadding="0" cellspacing="0">
+    <tr>
+        <td>P<span>A</span></td>
+    </tr>
+    <tr>
+        <td>S<span>S</span></td>
+    </tr>
+</table>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-unusual-html-elements-none.html b/testing/web-platform/tests/css/css-display/display-contents-unusual-html-elements-none.html
new file mode 100644
index 0000000000..53f5f9e5c7
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-unusual-html-elements-none.html
@@ -0,0 +1,33 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: display:contents and unusual HTML elements as display:none</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:futhark@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-display/#unbox-html">
+<link rel="match" href="display-contents-pass-ref.html">
+<style>
+  /* Disable kerning because kerning may differ for different node tree. */
+  html { font-kerning: none; font-feature-settings: "kern" off; }
+  body { overflow: hidden }
+  br, wbr, meter, progress, canvas, embed, object, audio, iframe, img, video,
+  input, textarea, select {
+    display: contents;
+    border: 10px solid red;
+    width: 200px; height: 200px;
+  }
+</style>
+<p>You should see the word PASS below.</p>
+<div>
+  <meter></meter>
+  <progress></progress>
+  <canvas></canvas>
+  <embed>
+  <object>FAIL</object>
+  <audio controls></audio>
+  <iframe></iframe>
+  <img>
+  <video></video>
+  <input></input>
+  <textarea></textarea>
+  <select></select>
+</div>
+P<br>A<wbr>S<br>S
diff --git a/testing/web-platform/tests/css/css-display/display-contents-whitespace-inside-inline-ref.html b/testing/web-platform/tests/css/css-display/display-contents-whitespace-inside-inline-ref.html
new file mode 100644
index 0000000000..135bc04d8e
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-whitespace-inside-inline-ref.html
@@ -0,0 +1,8 @@
+<!doctype html>
+<meta charset="utf-8">
+<title>CSS Test Reference</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
+<link rel="author" title="Mozilla" href="https://mozilla.org">
+
+<p>There should be an space between "Foo" and "bar" below</p>
+<span>Foo bar</span>
diff --git a/testing/web-platform/tests/css/css-display/display-contents-whitespace-inside-inline.html b/testing/web-platform/tests/css/css-display/display-contents-whitespace-inside-inline.html
new file mode 100644
index 0000000000..a97c02575b
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-contents-whitespace-inside-inline.html
@@ -0,0 +1,10 @@
+<!doctype html>
+<meta charset="utf-8">
+<title>CSS Test: Whitespace inside display: contents is preserved correctly.</title>
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
+<link rel="author" title="Mozilla" href="https://mozilla.org">
+<link rel="match" href="display-contents-whitespace-inside-inline-ref.html">
+
+<p>There should be an space between "Foo" and "bar" below</p>
+<span>Foo<div style="display: contents"> </div>bar</span>
diff --git a/testing/web-platform/tests/css/css-display/display-first-line-001.html b/testing/web-platform/tests/css/css-display/display-first-line-001.html
new file mode 100644
index 0000000000..6a714629e0
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-first-line-001.html
@@ -0,0 +1,42 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: first-line and first-letter pseudo-elements</title>
+<link rel="help" href="https://www.w3.org/TR/css-display-3/#placement">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<style>
+  #t1::first-letter { float: left; display: flex; font-size: 30px }
+  #t2::first-letter { float: left; font-size: 30px }
+  #t3::first-letter { display: flex; font-size: 30px }
+  #t4::first-letter { font-size: 30px }
+  #t5::first-line { float: left; display: flex; font-size: 30px }
+  #t6::first-line { float: left; font-size: 30px }
+  #t7::first-line { display: flex; font-size: 30px }
+  #t8::first-line { font-size: 30px }
+</style>
+<div id="t1">First letter is float and flex.</div>
+<div id="t2">First letter is float but not flex.</div>
+<div id="t3">First letter is flex but not float.</div>
+<div id="t4">First letter not float or flex.</div>
+<div id="t5">First line is float and flex.</div>
+<div id="t6">First line is float but not flex.</div>
+<div id="t7">First line is flex but not float.</div>
+<div id="t8">First line is not float or flex.</div>
+<script>
+  function getFirstLetterDisplayFor(id) {
+    return window.getComputedStyle(document.getElementById(id), "::first-letter").display;
+  }
+  function getFirstLineDisplayFor(id) {
+    return window.getComputedStyle(document.getElementById(id), "::first-line").display;
+  }
+  test(function() {
+    assert_equals(getFirstLetterDisplayFor("t1"), "block");
+    assert_equals(getFirstLetterDisplayFor("t2"), "block");
+    assert_equals(getFirstLetterDisplayFor("t3"), "inline");
+    assert_equals(getFirstLetterDisplayFor("t4"), "inline");
+    assert_equals(getFirstLineDisplayFor("t5"), "inline");
+    assert_equals(getFirstLineDisplayFor("t6"), "inline");
+    assert_equals(getFirstLineDisplayFor("t7"), "inline");
+    assert_equals(getFirstLineDisplayFor("t8"), "inline");
+  }, "display of first-letter and first-line");
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-first-line-002-ref.html b/testing/web-platform/tests/css/css-display/display-first-line-002-ref.html
new file mode 100644
index 0000000000..e82f6153a2
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-first-line-002-ref.html
@@ -0,0 +1,6 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<div contenteditable></div>
+<p>The word "PASS" should be seen below. There should be no DCHECK
+  failure.</p>
+<p style="color: blue;">PASS</p>
diff --git a/testing/web-platform/tests/css/css-display/display-first-line-002.html b/testing/web-platform/tests/css/css-display/display-first-line-002.html
new file mode 100644
index 0000000000..fef1d0b001
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-first-line-002.html
@@ -0,0 +1,28 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Display flex first line with floated first letter</title>
+<link rel="help" href="https://crbug.com/1097595">
+<link rel="match" href="display-first-line-002-ref.html">
+<style id="styleElm">
+  #victim::first-line { display:flex;  }
+  #victim::first-letter { float:right; }
+</style>
+
+<!-- The contenteditable DIV is just here to trigger legacy layout
+     fallback, and a DCHECK failure identical to the one in the bug
+     report. If we remove it, we'll get NG layout, and then it will
+     actually DCHECK-fail inside NG inline layout code instead. -->
+<div contenteditable></div>
+
+<p>The word "PASS" should be seen below. There should be no DCHECK
+  failure.</p>
+<div id="child" style="display:none;"></div>
+<div id="victim" style="width:fit-content;">
+  SPAS
+</div>
+<script>
+  document.body.offsetTop;
+  styleElm.appendChild(child);
+  document.body.offsetTop;
+  victim.style.color = "blue";
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-flow-root-001-ref.html b/testing/web-platform/tests/css/css-display/display-flow-root-001-ref.html
new file mode 100644
index 0000000000..fcb5ac277e
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-flow-root-001-ref.html
@@ -0,0 +1,51 @@
+<!DOCTYPE HTML>
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<html><head>
+  <meta charset="utf-8">
+  <title>Reference: display:flow-root</title>
+  <link rel="author" title="Mats Palmgren" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1322191">
+  <style type="text/css">
+html,body {
+  color:black; background-color:white; font:16px/1 monospace; padding:0; margin:0;
+}
+
+.float {
+  float: left;
+  width: 20px;
+  height: 40px;
+  background: pink;
+}
+
+.clearfix:after{content:".";display:block;height:0;clear:both;visibility:hidden;}
+
+  </style>
+</head>
+<body>
+
+<div style="border:1px solid">
+  <div style="margin: 40px 0">
+    <div>x</div>
+  </div>
+</div>
+
+<div style="border:1px solid">
+  <div class="float"></div>
+  <div class="clearfix"></div>
+</div>
+
+<div style="border:1px solid">
+  <div class="float"></div>
+  <div style="display:block; border:1px solid; margin-left:20px">x</div>
+</div>
+
+<span>
+  <span style="display:block; background:grey; margin:20px 0 0 21px"><div style="padding:20px">x</div></span>
+</span>
+
+<div style="border:3px solid; height:10px;"></div>
+
+</body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/display-flow-root-001.html b/testing/web-platform/tests/css/css-display/display-flow-root-001.html
new file mode 100644
index 0000000000..3d1dcb020d
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-flow-root-001.html
@@ -0,0 +1,56 @@
+<!DOCTYPE HTML>
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<html><head>
+  <meta charset="utf-8">
+  <title>CSS Display Test: display:flow-root</title>
+  <link rel="author" title="Mats Palmgren" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1322191">
+  <link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-flow-root">
+  <link rel="match" href="display-flow-root-001-ref.html">
+  <style type="text/css">
+html,body {
+  color:black; background-color:white; font:16px/1 monospace; padding:0; margin:0;
+}
+
+.float {
+  float: left;
+  width: 20px;
+  height: 40px;
+  background: pink;
+}
+
+  </style>
+</head>
+<body>
+
+<div style="border:1px solid">
+  <!-- this tests that the flow-root margins don't collapse with its children. -->
+  <span style="display:flow-root; margin: 20px 0">
+    <div style="margin: 20px 0">x</div>
+  </span>
+</div>
+
+<div style="border:1px solid">
+  <!-- this tests that the flow-root grows to fit child floats -->
+  <span style="display:flow-root"><div class="float"></div></span>
+</div>
+
+<div style="border:1px solid; margin-bottom:20px">
+  <!-- this tests that a float does not intrude into flow-root box -->
+  <div class="float"></div>
+  <span style="display:flow-root; border:1px solid">x</span>
+</div>
+
+<span>
+  <!-- this tests that a flow-root box is constructed also in the "ibsplit" case -->
+  <span style="display:flow-root; background:grey;"><div style="margin:20px">x</div></span>
+</span>
+
+<span style="display:flow-root; border:3px solid; height:10px;">
+  <!-- this tests that a flow-root fills the available width, and that 'height' applies -->
+</span>
+
+</body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/display-flow-root-002-ref.html b/testing/web-platform/tests/css/css-display/display-flow-root-002-ref.html
new file mode 100644
index 0000000000..014380f96e
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-flow-root-002-ref.html
@@ -0,0 +1,28 @@
+<!DOCTYPE HTML>
+<meta charset="utf-8">
+<title>Reference for CSS Display Test</title>
+<style>
+  .float {
+    background-color: blue;
+    width: 250px;
+    height: 100px;
+  }
+  .left { float: left; }
+  .right { float: right; }
+
+  #outer { position: relative; width: 400px; }
+
+  #zerowidth {
+    position: absolute;
+    top: 100px;
+    left: 250px;
+    width: 0;
+    outline: 1px solid black;
+    height: 200px;
+  }
+</style>
+<div id="outer">
+  <div class="float right"></div>
+  <div class="float left"></div>
+  <div id="zerowidth"></div>
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-flow-root-002.html b/testing/web-platform/tests/css/css-display/display-flow-root-002.html
new file mode 100644
index 0000000000..0640db93db
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-flow-root-002.html
@@ -0,0 +1,31 @@
+<!DOCTYPE HTML>
+<meta charset="utf-8">
+<title>CSS Display Test: div with display: flow-root and zero width does not intersect outer floats</title>
+<link rel="author" title="David Shin" href="mailto:dshin@mozilla.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-flow-root">
+<link rel="help" href="https://www.w3.org/TR/CSS21/visuren.html#floats">
+<link rel="match" href="display-flow-root-002-ref.html">
+<style>
+  .float {
+    background-color: blue;
+    width: 250px;
+    height: 100px;
+  }
+  .left { float: left; }
+  .right { float: right; }
+
+  #outer { width: 400px; }
+
+  #zerowidth {
+    display: flow-root;
+    width: 0;
+    outline: 1px solid black;
+    height: 200px;
+  }
+</style>
+<div id="outer">
+  <!-- Two floats are positioned and sized such that there is less than zero empty space "between" them. -->
+  <div class="float right"></div>
+  <div class="float left"></div>
+  <div id="zerowidth"></div>
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-flow-root-list-item-001-ref.html b/testing/web-platform/tests/css/css-display/display-flow-root-list-item-001-ref.html
new file mode 100644
index 0000000000..7d9199af42
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-flow-root-list-item-001-ref.html
@@ -0,0 +1,53 @@
+<!DOCTYPE HTML>
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<html><head>
+  <meta charset="utf-8">
+  <title>Reference: display:flow-root list-item</title>
+  <link rel="author" title="Mats Palmgren" href="">
+  <style type="text/css">
+html,body {
+  color:black; background-color:white; font:16px/1 monospace; padding:0; margin:0;
+}
+
+body { padding-left: 100px; }
+
+.float {
+  float: left;
+  width: 20px;
+  height: 40px;
+  background: pink;
+}
+
+.clearfix:after{content:".";display:block;height:0;clear:both;visibility:hidden;}
+
+  </style>
+</head>
+<body>
+
+<div style="border:1px solid">
+  <div style="margin: 40px 0">
+    <div style="display:list-item"><div>x</div></div>
+  </div>
+</div>
+
+<div style="border:1px solid">
+  <div style="display:list-item" class="float"></div>
+  <div class="clearfix"></div>
+</div>
+
+<div style="border:1px solid">
+  <div class="float"></div>
+  <div style="display:list-item; border:1px solid; margin-left:20px">x</div>
+</div>
+
+<span>
+  <div style="display:flow-root; margin-top:20px"><span style="display:list-item; background:grey"><div style="padding:20px">x</div></span></div>
+</span>
+
+<div style="display:list-item; border:3px solid; height:10px;"></div>
+
+</body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/display-flow-root-list-item-001.html b/testing/web-platform/tests/css/css-display/display-flow-root-list-item-001.html
new file mode 100644
index 0000000000..6c5bece586
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-flow-root-list-item-001.html
@@ -0,0 +1,59 @@
+<!DOCTYPE HTML>
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<html><head>
+  <meta charset="utf-8">
+  <title>CSS Display Test: display:flow-root list-item</title>
+  <link rel="author" title="Mats Palmgren" href="">
+  <link rel="help" href="https://drafts.csswg.org/css-display-3/#list-items">
+  <link rel="match" href="display-flow-root-list-item-001-ref.html">
+  <style type="text/css">
+html,body {
+  color:black; background-color:white; font:16px/1 monospace; padding:0; margin:0;
+}
+
+body { padding-left: 100px; }
+
+.float {
+  float: left;
+  width: 20px;
+  height: 40px;
+  background: pink;
+}
+
+.li { display: flow-root list-item; }
+  </style>
+</head>
+<body>
+
+<div style="border:1px solid">
+  <!-- this tests that the flow-root margins don't collapse with its children. -->
+  <span class="li" style="margin: 20px 0">
+    <div style="margin: 20px 0">x</div>
+  </span>
+</div>
+
+<div style="border:1px solid">
+  <!-- this tests that the flow-root grows to fit child floats -->
+  <span class="li"><div class="float"></div></span>
+</div>
+
+<div style="border:1px solid; margin-bottom:20px">
+  <!-- this tests that a float does not intrude into flow-root box -->
+  <div class="float"></div>
+  <span class="li" style="border:1px solid">x</span>
+</div>
+
+<span>
+  <!-- this tests that a flow-root box is constructed also in the "ibsplit" case -->
+  <span class="li" style="background:grey;"><div style="margin:20px">x</div></span>
+</span>
+
+<span class="li" style="border:3px solid; height:10px;">
+  <!-- this tests that a flow-root fills the available width, and that 'height' applies -->
+</span>
+
+</body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/display-inline-dynamic-001-ref.html b/testing/web-platform/tests/css/css-display/display-inline-dynamic-001-ref.html
new file mode 100644
index 0000000000..8b5f5015f9
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-inline-dynamic-001-ref.html
@@ -0,0 +1,4 @@
+<!DOCTYPE html>
+<style>div::first-line { font-family:monospace; color:green; }</style>
+<p>Test passes if PASS is displayed in green below.</p>
+<div>PASS</div>
diff --git a/testing/web-platform/tests/css/css-display/display-inline-dynamic-001.html b/testing/web-platform/tests/css/css-display/display-inline-dynamic-001.html
new file mode 100644
index 0000000000..7df697f940
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-inline-dynamic-001.html
@@ -0,0 +1,10 @@
+<!DOCTYPE html>
+<link rel="help" href="https://drafts.csswg.org/css-display/">
+<link rel="match" href="display-inline-dynamic-001-ref.html">
+<style>div::first-line { font-family:monospace; color:green; }</style>
+<p>Test passes if PASS is displayed in green below.</p>
+<div>P<span id="showme" style="display:none;">AS</span>S</div>
+<script>
+  document.body.offsetTop;
+  showme.style.display = "inline";
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-list-item-height-after-dom-change.html b/testing/web-platform/tests/css/css-display/display-list-item-height-after-dom-change.html
new file mode 100644
index 0000000000..f8d6e85cee
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-list-item-height-after-dom-change.html
@@ -0,0 +1,20 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Display: reflowing a display:list-item on dom changes - non-zero height</title>
+<link rel="author" title="Rune Lillesveen" href="mailto:futhark@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#list-items">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<ul>
+  <li id="item" style="background:green">
+    <div id="content" style="overflow:hidden">Text<div>
+  </li>
+</ul>
+<script>
+  test(function() {
+    document.body.offsetTop; // force layout
+    item.insertBefore(document.createTextNode("This text should have a green background"), item.firstChild);
+    content.innerHTML = "";
+    assert_not_equals(item.clientHeight, 0, "The height of the LI should not be 0px.");
+  }, "List item height after DOM change.");
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-math-on-non-mathml-elements.html b/testing/web-platform/tests/css/css-display/display-math-on-non-mathml-elements.html
new file mode 100644
index 0000000000..c2f0f5f9c9
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-math-on-non-mathml-elements.html
@@ -0,0 +1,31 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>display: math display values on non-MathML compute to flow</title>
+<link rel="help" href="https://drafts.csswg.org/css-display/#the-display-properties">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<div id="container">
+
+  <div data-expected="inline" style="display: math;"></div>
+  <div data-expected="inline" style="display: inline math;"></div>
+  <div data-expected="inline" style="display: math inline;"></div>
+  <div data-expected="block" style="display: block math;"></div>
+  <div data-expected="block" style="display: math block;"></div>
+
+  <svg data-expected="inline" style="display: math;"></svg>
+  <svg data-expected="inline" style="display: inline math;"></svg>
+  <svg data-expected="inline" style="display: math inline;"></svg>
+  <svg data-expected="block" style="display: block math;"></svg>
+  <svg data-expected="block" style="display: math block;"></svg>
+
+</div>
+
+<script>
+  Array.from(container.children).forEach(element => {
+      test(function() {
+          assert_equals(window.getComputedStyle(element).display,
+                        element.getAttribute('data-expected'));
+      }, `computed display on <${element.localName} style="${element.getAttribute('style')}">`);
+  });
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-math-on-pseudo-elements-001.html b/testing/web-platform/tests/css/css-display/display-math-on-pseudo-elements-001.html
new file mode 100644
index 0000000000..dbc2525a69
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-math-on-pseudo-elements-001.html
@@ -0,0 +1,30 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>display: math and inline-math on pseudo elements compute to flow</title>
+<link rel="help" href="https://drafts.csswg.org/css-display/#the-display-properties">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<style>
+  .inline::before { content: 'math'; display: math; }
+  .inline::after { content: 'math'; display: math; }
+  .block::before { content: 'math'; display: block math; }
+  .block::after { content: 'math'; display: block math; }
+</style>
+<div>
+  <div class="block"></div>
+  <math class="block"></math>
+  <math><mrow class="block"></mrow></math>
+  <div class="inline"></div>
+  <math class="inline"></math>
+  <math><mrow class="inline"></mrow></math>
+</div>
+<script>
+  Array.from(document.querySelectorAll('[class]')).forEach(element => {
+      test(function() {
+          assert_equals(window.getComputedStyle(element, "::before").display,
+                        element.getAttribute('class'));
+          assert_equals(window.getComputedStyle(element, "::after").display,
+                        element.getAttribute('class'));
+      }, `computed display on ::before and ::after for <${element.localName} class="${element.className}">`);
+  });
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-math-on-pseudo-elements-002-ref.html b/testing/web-platform/tests/css/css-display/display-math-on-pseudo-elements-002-ref.html
new file mode 100644
index 0000000000..7d7ba37637
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-math-on-pseudo-elements-002-ref.html
@@ -0,0 +1,17 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>display: block math and inline math on pseudo elements (reference)</title>
+<style>
+  .inline::before { content: 'math'; display: inline; }
+  .inline::after { content: 'math'; display: inline; }
+  .block::before { content: 'math'; display: block; }
+  .block::after { content: 'math'; display: block; }
+</style>
+<p>Test passes if SPAN and DIV are respectively surrounded by inline and block
+  "math" text.</p>
+<div>
+  <span class="inline">SPAN</span>
+</div>
+<div>
+  <span class="block">DIV</span>
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-math-on-pseudo-elements-002.html b/testing/web-platform/tests/css/css-display/display-math-on-pseudo-elements-002.html
new file mode 100644
index 0000000000..426adb6a23
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-math-on-pseudo-elements-002.html
@@ -0,0 +1,20 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>display: block math and inline math on pseudo elements</title>
+<link rel="help" href="https://drafts.csswg.org/css-display/#the-display-properties">
+<meta name="assert" content="display: inline math and display: block math on compute to flow">
+<link rel="match" href="display-math-on-pseudo-elements-002-ref.html">
+<style>
+  .inline::before { content: 'math'; display: math; }
+  .inline::after { content: 'math'; display: math; }
+  .block::before { content: 'math'; display: block math; }
+  .block::after { content: 'math'; display: block math; }
+</style>
+<p>Test passes if SPAN and DIV are respectively surrounded by inline and block
+  "math" text.</p>
+<div>
+  <span class="inline">SPAN</span>
+</div>
+<div>
+  <span class="block">DIV</span>
+</div>
diff --git a/testing/web-platform/tests/css/css-display/display-none-inline-img-ref.html b/testing/web-platform/tests/css/css-display/display-none-inline-img-ref.html
new file mode 100644
index 0000000000..a3e7369afb
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-none-inline-img-ref.html
@@ -0,0 +1,46 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test Reference</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<style>
+.carousel {
+  position: relative;
+  overflow: hidden;
+  height: 300px;
+}
+
+.scroller {
+  position: absolute;
+  top: 0;
+  left: 0;
+  right: 0;
+  bottom: 0;
+  overflow: auto;
+}
+
+.slides {
+  width: 200%;
+  display: flex;
+}
+
+.slide {
+  flex: 0 0 50%;
+  contain:  paint;
+}
+
+img {
+  width: 300px;
+  height: 250px;
+}
+</style>
+
+<div class="carousel">
+  <div class="scroller">
+    <div class="slides">
+      <div class="slide">
+        <img id="image" src="/images/green-256x256.png">
+      </div>
+    </div>
+  </div>
+</div>
+
diff --git a/testing/web-platform/tests/css/css-display/display-none-inline-img.html b/testing/web-platform/tests/css/css-display/display-none-inline-img.html
new file mode 100644
index 0000000000..f97ca7bbd3
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-none-inline-img.html
@@ -0,0 +1,70 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: display: none then inline on img</title>
+<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-inline">
+<link rel="match" href="display-none-inline-img-ref.html">
+<html class="reftest-wait">
+<style>
+.carousel {
+  position: relative;
+  overflow: hidden;
+  height: 300px;
+}
+
+.scroller {
+  position: absolute;
+  top: 0;
+  left: 0;
+  right: 0;
+  bottom: 0;
+  overflow: auto;
+}
+
+.slides {
+  width: 200%;
+  display: flex;
+}
+
+.slide {
+  flex: 0 0 50%;
+  contain:  paint;
+}
+
+img {
+  width: 300px;
+  height: 250px;
+}
+</style>
+
+<div class="carousel">
+  <div class="scroller">
+    <div class="slides">
+      <div class="slide">
+        <img id="image" src="/images/green-256x256.png">
+      </div>
+      <div class="slide">
+        <img>
+      </div>
+    </div>
+  </div>
+</div>
+
+<script>
+
+function toggleDisplay() {
+  var img = document.getElementById("image");
+  img.style.display = img.style.display == 'none' ? 'inline' : 'none';
+}
+
+window.onload = () => {
+  requestAnimationFrame(() => {
+    toggleDisplay();
+    requestAnimationFrame(() => {
+      toggleDisplay();
+      document.documentElement.classList.remove("reftest-wait");
+    });
+  });
+};
+</script>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/display-none-root-hit-test-crash.html b/testing/web-platform/tests/css/css-display/display-none-root-hit-test-crash.html
new file mode 100644
index 0000000000..b2467fa58f
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-none-root-hit-test-crash.html
@@ -0,0 +1,9 @@
+<!DOCTYPE html>
+<link rel="author" title="Morten Stenshorne" href="mailto:mstensho@chromium.org">
+<link rel="help" href="https://bugs.chromium.org/p/chromium/issues/detail?id=1409273">
+<style>
+  html { display: none; }
+</style>
+<script>
+  document.elementFromPoint(10, 10);
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-with-float-dynamic.html b/testing/web-platform/tests/css/css-display/display-with-float-dynamic.html
new file mode 100644
index 0000000000..7cc2fefcc4
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-with-float-dynamic.html
@@ -0,0 +1,40 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Computed float value of flex/grid items</title>
+<link rel="help" href="https://drafts.csswg.org/css-flexbox/#flex-containers">
+<link rel="help" href="https://drafts.csswg.org/css-grid-1/#grid-containers">
+<meta name="assert" content="computed float value of flex/grid items should be as specified">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<div id="flex" style="display:flex;">
+  <div id="flex-item"></div>
+</div>
+<div id="grid" style="display:grid;">
+  <div id="grid-item">
+</div>
+<script>
+  function setFloatFor(id, float) {
+    document.getElementById(id).style.cssFloat = float;
+  }
+  function getFloatFor(id) {
+    return window.getComputedStyle(document.getElementById(id)).getPropertyValue("float");
+  }
+  function setDisplayBlock(id) {
+    document.getElementById(id).style.display = "block";
+  }
+  test(function() {
+    assert_equals(getFloatFor("flex-item"), "none");
+    assert_equals(getFloatFor("grid-item"), "none");
+
+    setFloatFor("flex-item", "left");
+    setFloatFor("grid-item", "right");
+    assert_equals(getFloatFor("flex-item"), "left");
+    assert_equals(getFloatFor("grid-item"), "right");
+
+    setDisplayBlock("grid");
+    setDisplayBlock("flex");
+    assert_equals(getFloatFor("flex-item"), "left");
+    assert_equals(getFloatFor("grid-item"), "right");
+  }, "computed style for float");
+</script>
diff --git a/testing/web-platform/tests/css/css-display/display-with-float.html b/testing/web-platform/tests/css/css-display/display-with-float.html
new file mode 100644
index 0000000000..49f94799d9
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/display-with-float.html
@@ -0,0 +1,24 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Computed float value of flex/grid items</title>
+<link rel="help" href="https://drafts.csswg.org/css-flexbox/#flex-containers">
+<link rel="help" href="https://drafts.csswg.org/css-grid-1/#grid-containers">
+<meta name="assert" content="computed float value of flex/grid items should be as specified">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<div style="display:flex;">
+  <div id="flex-item" style="float:left;"></div>
+</div>
+<div style="display:grid;">
+  <div id="grid-item" style="float:right;"></div>
+</div>
+<script>
+  function getFloatFor(id) {
+    return window.getComputedStyle(document.getElementById(id)).getPropertyValue("float");
+  }
+  test(function() {
+    assert_equals(getFloatFor("flex-item"), "left");
+    assert_equals(getFloatFor("grid-item"), "right");
+  }, "computed style for float");
+</script>
diff --git a/testing/web-platform/tests/css/css-display/empty-text-baseline-001.html b/testing/web-platform/tests/css/css-display/empty-text-baseline-001.html
new file mode 100644
index 0000000000..a3a34f1fd2
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/empty-text-baseline-001.html
@@ -0,0 +1,45 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: An Empty Text Node Should Not Generate a Baseline</title>
+<link rel="author" title="David Shin" href="mailto:dshin@mozilla.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#intro">
+<link rel="help" href="https://github.com/w3c/csswg-drafts/issues/9606">
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1855583">
+<link rel="stylesheet" href="/fonts/ahem.css">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<style>
+body {
+  margin: 0;
+}
+
+#container {
+  font-family: Ahem;
+}
+
+#inner {
+  display: inline-block;
+}
+</style>
+<div id="container"><div id="inner">x</div><span id="span">x</span></div>
+<script>
+const expected = span.offsetTop;
+
+// Force an empty text node on the second line of #inner
+inner.appendChild(document.createElement("br"));
+inner.appendChild(document.createTextNode(''));
+
+test(function() {
+  assert_equals(span.offsetTop, expected);
+}, "Empty second line in #inner does not generate baseline for #span");
+
+test(function() {
+  inner.style = "white-space: pre-line";
+  assert_equals(span.offsetTop, expected);
+}, "Empty second line in #inner does not generate baseline for #span with white-space: pre-line");
+
+test(function() {
+  inner.style = "white-space: pre";
+  assert_equals(span.offsetTop, expected);
+}, "Empty second line in #inner does not generate baseline for #span with white-space: pre");
+</script>
diff --git a/testing/web-platform/tests/css/css-display/empty-text-baseline-002.html b/testing/web-platform/tests/css/css-display/empty-text-baseline-002.html
new file mode 100644
index 0000000000..ca9558a403
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/empty-text-baseline-002.html
@@ -0,0 +1,62 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: An Empty Text Node Should Not Generate a Baseline</title>
+<link rel="author" title="David Shin" href="mailto:dshin@mozilla.com">
+<link rel="help" href="https://drafts.csswg.org/css-display-3/#intro">
+<link rel="help" href="https://github.com/w3c/csswg-drafts/issues/9606">
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1855583">
+<link rel="stylesheet" href="/fonts/ahem.css">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<style>
+body {
+  margin: 0;
+}
+
+.ahem {
+  font-family: Ahem;
+}
+
+.with-pseudo::before, .with-pseudo::after {
+  content: "";
+  width: 4px;
+  height: 4px;
+  border: 2px solid;
+  background: orange;
+  display: inline-block;
+}
+
+.font-size::before, .font-size::after {
+  font-size: 100px;
+}
+
+.line-height::before, .line-height::after {
+  line-height: 10;
+}
+
+.empty-concat::before, .empty-concat::after {
+  content: "" "" "" "" "";
+}
+
+</style>
+<div id="reference" class="ahem">x</div>
+<div id="fs" class="ahem with-pseudo font-size">x</div>
+<div id="ba" class="ahem with-pseudo line-height">x</div>
+<div id="ec" class="ahem with-pseudo font-size empty-concat">x</div>
+<script>
+test(function() {
+  assert_equals(fs.offsetHeight, reference.offsetHeight);
+  assert_equals(ba.offsetHeight, reference.offsetHeight);
+  assert_equals(ec.offsetHeight, reference.offsetHeight);
+}, "Empty content pseudo-element does not generate baseline");
+
+test(function() {
+  const divs = [fs, ba, ec];
+  for (let d of divs) {
+    d.style = "white-space: pre";
+  }
+  assert_equals(fs.offsetHeight, reference.offsetHeight);
+  assert_equals(ba.offsetHeight, reference.offsetHeight);
+  assert_equals(ec.offsetHeight, reference.offsetHeight);
+}, "Empty content pseudo-element does not generate baseline with white-space: pre");
+</script>
diff --git a/testing/web-platform/tests/css/css-display/focus/display-contents-focus.html b/testing/web-platform/tests/css/css-display/focus/display-contents-focus.html
new file mode 100644
index 0000000000..8f1e2c5c90
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/focus/display-contents-focus.html
@@ -0,0 +1,49 @@
+<!doctype html>
+<html>
+<head>
+  <title>Testing focus for display: contents</title>
+  <link rel="help" href="https://drafts.csswg.org/css-display-4/#box-generation">
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/resources/testdriver.js"></script>
+  <script src="/resources/testdriver-vendor.js"></script>
+  <script src="/resources/testdriver-actions.js"></script>
+</head>
+<body>
+
+  <!-- Dec 2023 notes for "display: contents" testing:
+  - Per CSS spec, setting "display: contents" must not alter an element's semantics (https://www.w3.org/TR/css-display-3/#valdef-display-contents):
+  "As only the box tree is affected, any semantics based on the document tree, such as selector-matching, event handling, and
+  property inheritance, are not affected."
+
+  -->
+
+  <h1>Testing focusability of display: contents</h1>
+
+  <button style="display: contents;" class="ex-focusable" data-testname="button with display: contents is focusable">x</button>
+  <div role="button" tabindex="0" style="display: contents;" class="ex-focusable" data-testname="div with role button, tabindex=0 and display: contents is focusable"></div>
+  <div role="button" tabindex="-1" style="display: contents;" class="ex-focusable" data-testname="div with role button, tabindex=-1 and display: contents is focusable"></div>
+
+  <a href="#" style="display: contents;" class="ex-focusable" data-testname="link with display: contents is focusable">x</a>
+  <span role="link" tabindex="0" style="display: contents;" class="ex-focusable" data-testname="span with role link, tabindex=0 and display: contents is focusable"></span>
+
+<script>
+  verifyElementsAreFocusable();
+
+  function verifyElementsAreFocusable() {
+    const els = document.querySelectorAll(".ex-focusable");
+    if (!els.length) {
+      throw `Selector passed in verifyElementsAreFocusable should match at least one element.`;
+    }
+    for (const el of els) {
+      let testName = el.getAttribute("data-testname");
+      test(() => {
+        el.focus();
+        assert_equals(document.activeElement, el, "Element is focusable with element.focus()");
+      }, `${testName}`);
+    }
+  };
+</script>
+
+</body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/inheritance.html b/testing/web-platform/tests/css/css-display/inheritance.html
new file mode 100644
index 0000000000..bfd072651c
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/inheritance.html
@@ -0,0 +1,21 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>Inheritance of CSS display property</title>
+<link rel="help" href="https://drafts.csswg.org/css-display/#the-display-properties">
+<meta name="assert" content="Property 'display' does not inherit.">
+<meta name="assert" content="Property 'display' has initial value 'inline'.">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/css/support/inheritance-testcommon.js"></script>
+</head>
+<body>
+<div id="container">
+<div id="target"></div>
+</div>
+<script>
+assert_not_inherited('display', 'inline', 'table');
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/parsing/display-computed.html b/testing/web-platform/tests/css/css-display/parsing/display-computed.html
new file mode 100644
index 0000000000..c32f470e07
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/parsing/display-computed.html
@@ -0,0 +1,193 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>CSS Display: getComputedStyle().display</title>
+<link rel="help" href="https://drafts.csswg.org/css2/visuren.html#display-prop">
+<link rel="help" href="https://drafts.csswg.org/css-display/#the-display-properties">
+<link rel="help" href="https://drafts.csswg.org/css-grid-1/#grid-containers">
+<link rel="help" href="https://www.w3.org/TR/CSS2/visuren.html#dis-pos-flo">
+<meta name="assert" content="position and float can change display computed value.">
+<meta name="assert" content="display computed value is otherwise as specified.">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/css/support/computed-testcommon.js"></script>
+</head>
+<body>
+<div id="target"></div>
+<script>
+'use strict';
+
+// https://drafts.csswg.org/css-grid-1/#grid-containers
+test_computed_value("display", "grid");
+test_computed_value("display", "inline-grid");
+
+// https://drafts.csswg.org/css2/visuren.html#display-prop
+test_computed_value("display", "inline");
+test_computed_value("display", "block");
+test_computed_value("display", "list-item");
+test_computed_value("display", "inline-block");
+test_computed_value("display", "table");
+test_computed_value("display", "inline-table");
+test_computed_value("display", "table-row-group");
+test_computed_value("display", "table-header-group");
+test_computed_value("display", "table-footer-group");
+test_computed_value("display", "table-row");
+test_computed_value("display", "table-column-group");
+test_computed_value("display", "table-column");
+test_computed_value("display", "table-cell");
+test_computed_value("display", "table-caption");
+test_computed_value("display", "none");
+
+// https://drafts.csswg.org/css-flexbox-1/#flex-containers
+test_computed_value("display", "flex");
+test_computed_value("display", "inline-flex");
+
+test_computed_value("display", "contents");
+
+test_computed_value("display", "run-in");
+test_computed_value("display", "flow", "block");
+test_computed_value("display", "flow-root");
+test_computed_value("display", "ruby");
+test_computed_value("display", "ruby-base");
+test_computed_value("display", "ruby-text");
+
+test_computed_value("display", "flow list-item", "list-item");
+test_computed_value("display", "list-item flow", "list-item");
+test_computed_value("display", "flow-root list-item", "flow-root list-item");
+test_computed_value("display", "list-item flow-root", "flow-root list-item");
+
+test_computed_value("display", "block flow", "block");
+test_computed_value("display", "flow block", "block");
+test_computed_value("display", "flow-root block", "flow-root");
+test_computed_value("display", "block flow-root", "flow-root");
+test_computed_value("display", "flex block", "flex");
+test_computed_value("display", "block flex", "flex");
+test_computed_value("display", "grid block", "grid");
+test_computed_value("display", "block grid", "grid");
+test_computed_value("display", "table block", "table");
+test_computed_value("display", "block table", "table");
+test_computed_value("display", "block ruby", "block ruby");
+test_computed_value("display", "ruby block", "block ruby");
+test_computed_value("display", "block list-item", "list-item");
+test_computed_value("display", "list-item block", "list-item");
+test_computed_value("display", "flow block list-item", "list-item");
+test_computed_value("display", "block flow list-item", "list-item");
+test_computed_value("display", "flow list-item block", "list-item");
+test_computed_value("display", "block list-item flow", "list-item");
+test_computed_value("display", "list-item block flow", "list-item");
+test_computed_value("display", "list-item flow block", "list-item");
+test_computed_value("display", "flow-root block list-item", "flow-root list-item");
+test_computed_value("display", "block flow-root list-item", "flow-root list-item");
+test_computed_value("display", "flow-root list-item block", "flow-root list-item");
+test_computed_value("display", "block list-item flow-root", "flow-root list-item");
+test_computed_value("display", "list-item block flow-root", "flow-root list-item");
+test_computed_value("display", "list-item flow-root block", "flow-root list-item");
+
+test_computed_value("display", "inline flow", "inline");
+test_computed_value("display", "flow inline", "inline");
+test_computed_value("display", "flow-root inline", "inline-block");
+test_computed_value("display", "inline flow-root", "inline-block");
+test_computed_value("display", "flex inline", "inline-flex");
+test_computed_value("display", "inline flex", "inline-flex");
+test_computed_value("display", "grid inline", "inline-grid");
+test_computed_value("display", "inline grid", "inline-grid");
+test_computed_value("display", "table inline", "inline-table");
+test_computed_value("display", "inline table", "inline-table");
+test_computed_value("display", "inline ruby", "ruby");
+test_computed_value("display", "ruby inline", "ruby");
+test_computed_value("display", "inline list-item", "inline list-item");
+test_computed_value("display", "list-item inline", "inline list-item");
+test_computed_value("display", "flow inline list-item", "inline list-item");
+test_computed_value("display", "inline flow list-item", "inline list-item");
+test_computed_value("display", "flow list-item inline", "inline list-item");
+test_computed_value("display", "inline list-item flow", "inline list-item");
+test_computed_value("display", "list-item inline flow", "inline list-item");
+test_computed_value("display", "list-item flow inline", "inline list-item");
+test_computed_value("display", "flow-root inline list-item", "inline flow-root list-item");
+test_computed_value("display", "inline flow-root list-item", "inline flow-root list-item");
+test_computed_value("display", "flow-root list-item inline", "inline flow-root list-item");
+test_computed_value("display", "inline list-item flow-root", "inline flow-root list-item");
+test_computed_value("display", "list-item inline flow-root", "inline flow-root list-item");
+test_computed_value("display", "list-item flow-root inline", "inline flow-root list-item");
+
+test_computed_value("display", "run-in flow", "run-in");
+test_computed_value("display", "flow run-in", "run-in");
+test_computed_value("display", "flow-root run-in", "run-in flow-root");
+test_computed_value("display", "run-in flow-root", "run-in flow-root");
+test_computed_value("display", "flex run-in", "run-in flex");
+test_computed_value("display", "run-in flex", "run-in flex");
+test_computed_value("display", "grid run-in", "run-in grid");
+test_computed_value("display", "run-in grid", "run-in grid");
+test_computed_value("display", "table run-in", "run-in table");
+test_computed_value("display", "run-in table", "run-in table");
+test_computed_value("display", "run-in ruby", "run-in ruby");
+test_computed_value("display", "ruby run-in", "run-in ruby");
+test_computed_value("display", "run-in list-item", "run-in list-item");
+test_computed_value("display", "list-item run-in", "run-in list-item");
+test_computed_value("display", "flow run-in list-item", "run-in list-item");
+test_computed_value("display", "run-in flow list-item", "run-in list-item");
+test_computed_value("display", "flow list-item run-in", "run-in list-item");
+test_computed_value("display", "run-in list-item flow", "run-in list-item");
+test_computed_value("display", "list-item run-in flow", "run-in list-item");
+test_computed_value("display", "list-item flow run-in", "run-in list-item");
+test_computed_value("display", "flow-root run-in list-item", "run-in flow-root list-item");
+test_computed_value("display", "run-in flow-root list-item", "run-in flow-root list-item");
+test_computed_value("display", "flow-root list-item run-in", "run-in flow-root list-item");
+test_computed_value("display", "run-in list-item flow-root", "run-in flow-root list-item");
+test_computed_value("display", "list-item run-in flow-root", "run-in flow-root list-item");
+test_computed_value("display", "list-item flow-root run-in", "run-in flow-root list-item");
+
+// https://www.w3.org/TR/CSS2/visuren.html#dis-pos-flo
+function test_display_affected(property, value) {
+  const target = document.getElementById('target');
+  test(() => {
+    target.style[property] = value;
+    target.style.display = 'inline-table';
+    assert_equals(getComputedStyle(target).display, 'table', 'inline-table -> block');
+
+    const displayValues = [
+      'inline',
+      'table-row-group',
+      'table-column',
+      'table-column-group',
+      'table-header-group',
+      'table-footer-group',
+      'table-row',
+      'table-cell',
+      'table-caption',
+      'ruby-base',
+      'ruby-text',
+      'inline-block'
+    ];
+
+    for (let displayValue of displayValues) {
+      target.style.display = displayValue;
+      assert_equals(getComputedStyle(target).display, 'block', displayValue + ' -> block');
+    }
+
+    target.style.display = 'inline-flex';
+    assert_equals(getComputedStyle(target).display, 'flex', 'inline-flex -> flex');
+
+    target.style.display = 'inline-grid';
+    assert_equals(getComputedStyle(target).display, 'grid', 'inline-grid -> grid');
+
+    // Other values are not affected.
+    target.style.display = 'list-item';
+    assert_equals(getComputedStyle(target).display, 'list-item', 'list-item -> list-item');
+
+    target.style.display = 'contents';
+    assert_equals(getComputedStyle(target).display, 'contents', 'contents -> contents');
+
+    target.style[property] = '';
+    target.style.display = '';
+  }, property + ' ' + value + ' affects computed display');
+}
+
+test_display_affected("position", "absolute");
+test_display_affected("position", "fixed");
+test_display_affected("float", "left");
+test_display_affected("float", "right");
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/parsing/display-invalid.html b/testing/web-platform/tests/css/css-display/parsing/display-invalid.html
new file mode 100644
index 0000000000..7c4054747e
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/parsing/display-invalid.html
@@ -0,0 +1,75 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>CSS Display: parsing display with invalid values</title>
+<link rel="author" title="Eric Willigers" href="mailto:ericwilligers@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css2/visuren.html#display-prop">
+<link rel="help" href="https://drafts.csswg.org/css-display/#the-display-properties">
+<link rel="help" href="https://drafts.csswg.org/css-grid-1/#grid-containers">
+<meta name="assert" content="display supports only the spec grammar.">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/css/support/parsing-testcommon.js"></script>
+</head>
+<body>
+<script>
+test_invalid_value("display", "grid inline-grid");
+test_invalid_value("display", "none grid");
+test_invalid_value("display", "none flow");
+test_invalid_value("display", "none ruby");
+test_invalid_value("display", "none flow-root");
+test_invalid_value("display", "none list-item");
+test_invalid_value("display", "contents list-item");
+test_invalid_value("display", "list-item contents");
+test_invalid_value("display", "flow flow");
+test_invalid_value("display", "block block");
+test_invalid_value("display", "flow flow-root");
+test_invalid_value("display", "flow-root flow-root");
+test_invalid_value("display", "block inline");
+test_invalid_value("display", "flex ruby");
+test_invalid_value("display", "ruby flex");
+test_invalid_value("display", "inline inline");
+test_invalid_value("display", "flex flex");
+test_invalid_value("display", "grid flex");
+test_invalid_value("display", "ruby grid");
+test_invalid_value("display", "flex grid");
+test_invalid_value("display", "grid table");
+test_invalid_value("display", "table flex");
+test_invalid_value("display", "flex table");
+test_invalid_value("display", "ruby table");
+test_invalid_value("display", "table table");
+test_invalid_value("display", "table flow-root");
+test_invalid_value("display", "flow-root ruby");
+test_invalid_value("display", "list-item list-item");
+test_invalid_value("display", "list-item table");
+test_invalid_value("display", "flex list-item");
+test_invalid_value("display", "list-item grid");
+test_invalid_value("display", "flow flow list-item");
+test_invalid_value("display", "grid flow list-item");
+test_invalid_value("display", "flow list-item flow");
+test_invalid_value("display", "block list-item block");
+test_invalid_value("display", "list-item flow-root flow");
+test_invalid_value("display", "list-item block block");
+test_invalid_value("display", "list-item block list-item");
+test_invalid_value("display", "list-item flow-root list-item");
+test_invalid_value("display", "list-item flow-root block list-item");
+test_invalid_value("display", "list-item block flow-root list-item");
+test_invalid_value("display", "block list-item flow-root list-item");
+test_invalid_value("display", "flow-root list-item block list-item");
+test_invalid_value("display", "list-item ruby");
+test_invalid_value("display", "ruby list-item");
+test_invalid_value("display", "ruby ruby");
+test_invalid_value("display", "ruby flow");
+test_invalid_value("display", "flow ruby");
+test_invalid_value("display", "ruby flow-root");
+test_invalid_value("display", "grid ruby");
+test_invalid_value("display", "table ruby");
+test_invalid_value("display", "table-row flow");
+test_invalid_value("display", "flow table-row");
+test_invalid_value("display", "table-row-group flow-root");
+test_invalid_value("display", "flex table-row-group");
+
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/parsing/display-valid.html b/testing/web-platform/tests/css/css-display/parsing/display-valid.html
new file mode 100644
index 0000000000..c011c2a30c
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/parsing/display-valid.html
@@ -0,0 +1,141 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>CSS Display: parsing display with valid values</title>
+<link rel="author" title="Eric Willigers" href="mailto:ericwilligers@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css2/visuren.html#display-prop">
+<link rel="help" href="https://drafts.csswg.org/css-display/#the-display-properties">
+<link rel="help" href="https://drafts.csswg.org/css-grid-1/#grid-containers">
+<meta name="assert" content="display supports the full spec grammar.">
+<meta name="assert" content="display supports the new values 'grid | inline-grid'.">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/css/support/parsing-testcommon.js"></script>
+</head>
+<body>
+<script>
+// https://drafts.csswg.org/css-grid-1/#grid-containers
+test_valid_value("display", "grid");
+test_valid_value("display", "inline-grid");
+
+// https://drafts.csswg.org/css2/visuren.html#display-prop
+test_valid_value("display", "inline");
+test_valid_value("display", "block");
+test_valid_value("display", "list-item");
+test_valid_value("display", "inline-block");
+test_valid_value("display", "table");
+test_valid_value("display", "inline-table");
+test_valid_value("display", "table-row-group");
+test_valid_value("display", "table-header-group");
+test_valid_value("display", "table-footer-group");
+test_valid_value("display", "table-row");
+test_valid_value("display", "table-column-group");
+test_valid_value("display", "table-column");
+test_valid_value("display", "table-cell");
+test_valid_value("display", "table-caption");
+test_valid_value("display", "none");
+
+// https://drafts.csswg.org/css-flexbox-1/#flex-containers
+test_valid_value("display", "flex");
+test_valid_value("display", "inline-flex");
+
+test_valid_value("display", "contents");
+
+// https://drafts.csswg.org/css-display/#the-display-properties
+test_valid_value("display", "run-in");
+test_valid_value("display", "flow");
+test_valid_value("display", "flow-root");
+test_valid_value("display", "ruby");
+test_valid_value("display", "ruby-base");
+test_valid_value("display", "ruby-text");
+
+test_valid_value("display", "flow list-item", "list-item");
+test_valid_value("display", "list-item flow", "list-item");
+test_valid_value("display", "flow-root list-item", "flow-root list-item");
+test_valid_value("display", "list-item flow-root", "flow-root list-item");
+
+test_valid_value("display", "block flow", "block");
+test_valid_value("display", "flow block", "block");
+test_valid_value("display", "flow-root block", "flow-root");
+test_valid_value("display", "block flow-root", "flow-root");
+test_valid_value("display", "flex block", "flex");
+test_valid_value("display", "block flex", "flex");
+test_valid_value("display", "grid block", "grid");
+test_valid_value("display", "block grid", "grid");
+test_valid_value("display", "table block", "table");
+test_valid_value("display", "block table", "table");
+test_valid_value("display", "block ruby", "block ruby");
+test_valid_value("display", "ruby block", "block ruby");
+test_valid_value("display", "block list-item", "list-item");
+test_valid_value("display", "list-item block", "list-item");
+test_valid_value("display", "flow block list-item", "list-item");
+test_valid_value("display", "block flow list-item", "list-item");
+test_valid_value("display", "flow list-item block", "list-item");
+test_valid_value("display", "block list-item flow", "list-item");
+test_valid_value("display", "list-item block flow", "list-item");
+test_valid_value("display", "list-item flow block", "list-item");
+test_valid_value("display", "flow-root block list-item", "flow-root list-item");
+test_valid_value("display", "block flow-root list-item", "flow-root list-item");
+test_valid_value("display", "flow-root list-item block", "flow-root list-item");
+test_valid_value("display", "block list-item flow-root", "flow-root list-item");
+test_valid_value("display", "list-item block flow-root", "flow-root list-item");
+test_valid_value("display", "list-item flow-root block", "flow-root list-item");
+
+test_valid_value("display", "inline flow", "inline");
+test_valid_value("display", "flow inline", "inline");
+test_valid_value("display", "flow-root inline", "inline flow-root");
+test_valid_value("display", "inline flow-root");
+test_valid_value("display", "flex inline", "inline flex");
+test_valid_value("display", "inline flex");
+test_valid_value("display", "grid inline", "inline grid");
+test_valid_value("display", "inline grid");
+test_valid_value("display", "table inline", "inline table");
+test_valid_value("display", "inline table");
+test_valid_value("display", "inline ruby", "ruby");
+test_valid_value("display", "ruby inline", "ruby");
+test_valid_value("display", "inline list-item", "inline list-item");
+test_valid_value("display", "list-item inline", "inline list-item");
+test_valid_value("display", "flow inline list-item", "inline list-item");
+test_valid_value("display", "inline flow list-item", "inline list-item");
+test_valid_value("display", "flow list-item inline", "inline list-item");
+test_valid_value("display", "inline list-item flow", "inline list-item");
+test_valid_value("display", "list-item inline flow", "inline list-item");
+test_valid_value("display", "list-item flow inline", "inline list-item");
+test_valid_value("display", "flow-root inline list-item", "inline flow-root list-item");
+test_valid_value("display", "inline flow-root list-item", "inline flow-root list-item");
+test_valid_value("display", "flow-root list-item inline", "inline flow-root list-item");
+test_valid_value("display", "inline list-item flow-root", "inline flow-root list-item");
+test_valid_value("display", "list-item inline flow-root", "inline flow-root list-item");
+test_valid_value("display", "list-item flow-root inline", "inline flow-root list-item");
+
+test_valid_value("display", "run-in flow", "run-in");
+test_valid_value("display", "flow run-in", "run-in");
+test_valid_value("display", "flow-root run-in", "run-in flow-root");
+test_valid_value("display", "run-in flow-root", "run-in flow-root");
+test_valid_value("display", "flex run-in", "run-in flex");
+test_valid_value("display", "run-in flex", "run-in flex");
+test_valid_value("display", "grid run-in", "run-in grid");
+test_valid_value("display", "run-in grid", "run-in grid");
+test_valid_value("display", "table run-in", "run-in table");
+test_valid_value("display", "run-in table", "run-in table");
+test_valid_value("display", "run-in ruby", "run-in ruby");
+test_valid_value("display", "ruby run-in", "run-in ruby");
+test_valid_value("display", "run-in list-item", "run-in list-item");
+test_valid_value("display", "list-item run-in", "run-in list-item");
+test_valid_value("display", "flow run-in list-item", "run-in list-item");
+test_valid_value("display", "run-in flow list-item", "run-in list-item");
+test_valid_value("display", "flow list-item run-in", "run-in list-item");
+test_valid_value("display", "run-in list-item flow", "run-in list-item");
+test_valid_value("display", "list-item run-in flow", "run-in list-item");
+test_valid_value("display", "list-item flow run-in", "run-in list-item");
+test_valid_value("display", "flow-root run-in list-item", "run-in flow-root list-item");
+test_valid_value("display", "run-in flow-root list-item", "run-in flow-root list-item");
+test_valid_value("display", "flow-root list-item run-in", "run-in flow-root list-item");
+test_valid_value("display", "run-in list-item flow-root", "run-in flow-root list-item");
+test_valid_value("display", "list-item run-in flow-root", "run-in flow-root list-item");
+test_valid_value("display", "list-item flow-root run-in", "run-in flow-root list-item");
+
+</script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/after-content-display-004.xht b/testing/web-platform/tests/css/css-display/run-in/after-content-display-004.xht
new file mode 100644
index 0000000000..4a99ba2ee1
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/after-content-display-004.xht
@@ -0,0 +1,33 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+
+<html xmlns="http://www.w3.org/1999/xhtml">
+
+ <head>
+
+  <title>CSS Test: :after generated content - display run-in</title>
+
+  <link rel="author" title="Gérard Talbot" href="http://www.gtalbot.org/BrowserBugsSection/css21testsuite/" />
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/generate.html#before-after-content" title="12.1 The :before and :after pseudo-elements" />
+  <link rel="help" href="http://www.w3.org/TR/css3-box/#run-in-boxes" title="4.3. Run-in boxes" />
+
+  <meta content="Generated content can have their own display value explicitly set in which case they behave as if they were real elements inserted just inside their associated element." name="assert" />
+
+  <style type="text/css"><![CDATA[
+  div:after
+  {
+  content: "Filler text";
+  display: run-in;
+  }
+  ]]></style>
+
+ </head>
+
+ <body>
+
+  <p>Test passes if there are <strong>2 lines of "Filler text"</strong>.</p>
+
+  <div>Filler text</div>
+
+ </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/anonymous-box-generation-002.xht b/testing/web-platform/tests/css/css-display/run-in/anonymous-box-generation-002.xht
new file mode 100644
index 0000000000..deb9af1f32
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/anonymous-box-generation-002.xht
@@ -0,0 +1,32 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Anonymous run-in box generation</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#anonymous-block-level" />
+        <meta name="assert" content="Block boxes with inline content followed by a run-in box generate an anonymous run-in box around the inline content." />
+        <style type="text/css">
+            div
+            {
+                width: 2in;
+            }
+            #div1
+            {
+                text-align: center;
+            }
+            div div
+            {
+                background: blue;
+                display: run-in;
+                height: 1em;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the "Filler Text" text is centered above the blue box.</p>
+        <div id="div1">
+            Filler Text
+            <div></div>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/background-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/background-applies-to-011.xht
new file mode 100644
index 0000000000..9994af0ce6
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/background-applies-to-011.xht
@@ -0,0 +1,23 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Background applied to elements with 'display' set to 'run-in'</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/colors.html#propdef-background" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/colors.html#background-properties" />
+        <meta name="assert" content="The 'background' property applies to elements with 'display' set to 'run-in'." />
+        <style type="text/css">
+            div
+            {
+                background: black;
+                display: run-in;
+                height: 1in;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a black box below.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/background-attachment-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/background-attachment-applies-to-011.xht
new file mode 100644
index 0000000000..9f2c78913b
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/background-attachment-applies-to-011.xht
@@ -0,0 +1,27 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Background-attachment applied to elements with 'display' set to 'run-in'</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/colors.html#propdef-background-attachment" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/colors.html#background-properties" />
+        <meta name="flags" content="image" />
+        <meta name="assert" content="The 'background-attachment' property applies to elements with 'display' set to 'run-in'." />
+        <style type="text/css">
+            div
+            {
+                background-color: orange;
+                background-image: url('support/blue96x96.png');
+                background-attachment: fixed;
+                background-repeat: repeat-x;
+                display: run-in;
+                height: 2in;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a short blue box above a taller orange box below.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/background-color-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/background-color-applies-to-011.xht
new file mode 100644
index 0000000000..c930a4a36f
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/background-color-applies-to-011.xht
@@ -0,0 +1,23 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Background-color applied to elements with 'display' set to 'run-in'</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/colors.html#propdef-background-color" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/colors.html#background-properties" />
+        <meta name="assert" content="The 'background-color' property applies to elements with 'display' set to 'run-in'." />
+        <style type="text/css">
+            div
+            {
+                background-color: black;
+                display: run-in;
+                height: 1in;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the box below is black.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/background-image-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/background-image-applies-to-011.xht
new file mode 100644
index 0000000000..84ade79760
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/background-image-applies-to-011.xht
@@ -0,0 +1,24 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Background-image applied to elements with 'display' set to 'run-in'</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/colors.html#propdef-background-image" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/colors.html#background-properties" />
+        <meta name="flags" content="image" />
+        <meta name="assert" content="The 'background-image' property applies to elements with 'display' set to 'run-in'." />
+        <style type="text/css">
+            div
+            {
+                background-image: url('support/black15x15.png');
+                display: run-in;
+                height: 1in;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a box below.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/background-position-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/background-position-applies-to-011.xht
new file mode 100644
index 0000000000..33b3cb8c16
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/background-position-applies-to-011.xht
@@ -0,0 +1,27 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Background-position applied to elements with 'display' set to 'run-in'</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/colors.html#propdef-background-position" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/colors.html#background-properties" />
+        <meta name="flags" content="image" />
+        <meta name="assert" content="The 'background-position' property applies to elements with 'display' set to 'run-in'." />
+        <style type="text/css">
+            div
+            {
+                background-image: url('support/blue15x15.png');
+                background-position: bottom right;
+                background-repeat: no-repeat;
+                border: solid black;
+                display: run-in;
+                height: 1in;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the blue box is in the lower-right corner of the black box.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/background-repeat-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/background-repeat-applies-to-011.xht
new file mode 100644
index 0000000000..236b30a5ad
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/background-repeat-applies-to-011.xht
@@ -0,0 +1,26 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Background-repeat applied to elements with 'display' set to 'run-in'</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/colors.html#propdef-background-repeat" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/colors.html#background-properties" />
+        <meta name="flags" content="image" />
+        <meta name="assert" content="The 'background-repeat' property applies to elements with 'display' set to 'run-in'." />
+        <style type="text/css">
+            div
+            {
+                background-color: red;
+                background-image: url('support/green15x15.png');
+                background-repeat: repeat;
+                display: run-in;
+                height: 1in;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a green box below and no red visible on the page.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/before-content-display-004.xht b/testing/web-platform/tests/css/css-display/run-in/before-content-display-004.xht
new file mode 100644
index 0000000000..d1cc892056
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/before-content-display-004.xht
@@ -0,0 +1,33 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+
+<html xmlns="http://www.w3.org/1999/xhtml">
+
+ <head>
+
+  <title>CSS Test: :before generated content - display run-in</title>
+
+  <link rel="author" title="Gérard Talbot" href="http://www.gtalbot.org/BrowserBugsSection/css21testsuite/" />
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/generate.html#before-after-content" title="12.1 The :before and :after pseudo-elements" />
+  <link rel="help" href="http://www.w3.org/TR/css3-box/#run-in-boxes" title="4.3. Run-in boxes" />
+
+  <meta content="Generated content can have their own display value explicitly set in which case they behave as if they were real elements inserted just inside their associated element." name="assert" />
+
+  <style type="text/css"><![CDATA[
+  div:before
+  {
+  content: "Filler text ";
+  display: run-in;
+  }
+  ]]></style>
+
+ </head>
+
+ <body>
+
+  <p>Test passes if the 2 "Filler text" are both <strong>on the same line</strong>.</p>
+
+  <div>Filler text</div>
+
+ </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/border-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/border-applies-to-011.xht
new file mode 100644
index 0000000000..98b062db27
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/border-applies-to-011.xht
@@ -0,0 +1,23 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Border applied to element with 'display' set to run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#propdef-border" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#border-shorthand-properties" />
+        <meta name="assert" content="The 'border' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                border: solid green;
+                display: run-in;
+                height: 1in;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a hollow box below.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/border-bottom-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/border-bottom-applies-to-011.xht
new file mode 100644
index 0000000000..fb176f6c70
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/border-bottom-applies-to-011.xht
@@ -0,0 +1,22 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Border-bottom applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#propdef-border-bottom" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#border-shorthand-properties" />
+        <meta name="assert" content="The 'border-bottom' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                border-bottom: solid green;
+                display: run-in;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a green line below.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/border-bottom-color-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/border-bottom-color-applies-to-011.xht
new file mode 100644
index 0000000000..21541842e8
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/border-bottom-color-applies-to-011.xht
@@ -0,0 +1,23 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Border-bottom-color applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#propdef-border-bottom-color" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#border-color-properties" />
+        <meta name="assert" content="The 'border-bottom-color' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                border-bottom-style: solid;
+                border-bottom-color: green;
+                display: run-in;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the line below is green.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/border-bottom-style-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/border-bottom-style-applies-to-011.xht
new file mode 100644
index 0000000000..746063bb9d
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/border-bottom-style-applies-to-011.xht
@@ -0,0 +1,22 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Border-bottom-style applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#propdef-border-bottom-style" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#border-style-properties" />
+        <meta name="assert" content="The 'border-bottom-style' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                border-bottom-style: dashed;
+                display: run-in;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the line below is dashed.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/border-bottom-width-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/border-bottom-width-applies-to-011.xht
new file mode 100644
index 0000000000..b32c4c54bd
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/border-bottom-width-applies-to-011.xht
@@ -0,0 +1,23 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Border-bottom-width applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#propdef-border-bottom-width" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#border-width-properties" />
+        <meta name="assert" content="The 'border-bottom-width' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                border-bottom-style: solid;
+                border-bottom-width: 1in;
+                display: run-in;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a square below.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/border-collapse-applies-to-004.xht b/testing/web-platform/tests/css/css-display/run-in/border-collapse-applies-to-004.xht
new file mode 100644
index 0000000000..d83718ea81
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/border-collapse-applies-to-004.xht
@@ -0,0 +1,32 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Border-collapse and 'display: run-in' elements</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/tables.html#propdef-border-collapse" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/tables.html#borders" />
+        <meta name="assert" content="Border-collapse does not apply to 'display: run-in' elements." />
+        <style type="text/css">
+            div
+            {
+                border-collapse: collapse;
+                display: run-in;
+                height: 100px;
+                width: 100px;
+            }
+            #top
+            {
+                border-bottom: 10px solid blue;
+            }
+            #bottom
+            {
+                border-top: 10px dotted orange;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if below there is a horizontal solid blue line above a dotted orange line.</p>
+        <div id="top"></div>
+        <div id="bottom"></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/border-color-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/border-color-applies-to-011.xht
new file mode 100644
index 0000000000..8f29f03af2
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/border-color-applies-to-011.xht
@@ -0,0 +1,24 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Border-color applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#propdef-border-color" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#border-color-properties" />
+        <meta name="assert" content="The 'border-color' properties applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                border-style: solid;
+                border-color: green;
+                display: run-in;
+                height: 1in;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a green box below.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/border-left-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/border-left-applies-to-011.xht
new file mode 100644
index 0000000000..80cd899214
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/border-left-applies-to-011.xht
@@ -0,0 +1,22 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Border-left applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#propdef-border-left" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#border-shorthand-properties" />
+        <meta name="assert" content="The 'border-left' properties applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                border-left: solid green;
+                display: run-in;
+                height: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a green line below.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/border-left-color-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/border-left-color-applies-to-011.xht
new file mode 100644
index 0000000000..1f271d0d09
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/border-left-color-applies-to-011.xht
@@ -0,0 +1,23 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Border-left-color applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#propdef-border-left-color" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#border-color-properties" />
+        <meta name="assert" content="The 'border-left-color' properties applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                border-left-style: solid;
+                border-left-color: green;
+                display: run-in;
+                height: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the line below is green.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/border-left-style-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/border-left-style-applies-to-011.xht
new file mode 100644
index 0000000000..2ab73f4536
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/border-left-style-applies-to-011.xht
@@ -0,0 +1,22 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Border-left-style applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#propdef-border-left-style" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#border-style-properties" />
+        <meta name="assert" content="The 'border-left-style' properties applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                border-left-style: dashed;
+                display: run-in;
+                height: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the line below is dashed.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/border-left-width-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/border-left-width-applies-to-011.xht
new file mode 100644
index 0000000000..8da0710f03
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/border-left-width-applies-to-011.xht
@@ -0,0 +1,23 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Border-left-width applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#propdef-border-left-width" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#border-width-properties" />
+        <meta name="assert" content="The 'border-left-width' properties applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                border-left-style: solid;
+                border-left-width: 1in;
+                display: run-in;
+                height: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a square below.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/border-right-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/border-right-applies-to-011.xht
new file mode 100644
index 0000000000..4b81ed2190
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/border-right-applies-to-011.xht
@@ -0,0 +1,23 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Border-right applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#propdef-border-right" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#border-shorthand-properties" />
+        <meta name="assert" content="The 'border-right' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                border-right: solid green;
+                display: run-in;
+                height: 1in;
+                width: 0;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a green line below.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/border-right-color-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/border-right-color-applies-to-011.xht
new file mode 100644
index 0000000000..6b6853da3f
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/border-right-color-applies-to-011.xht
@@ -0,0 +1,24 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Border-right-color applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#propdef-border-right-color" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#border-color-properties" />
+        <meta name="assert" content="The 'border-right-color' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                border-right-style: solid;
+                border-right-color: green;
+                display: run-in;
+                height: 1in;
+                width: 0;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the line below is green.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/border-right-style-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/border-right-style-applies-to-011.xht
new file mode 100644
index 0000000000..9768edfb11
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/border-right-style-applies-to-011.xht
@@ -0,0 +1,23 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Border-right-style applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#propdef-border-right-style" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#border-style-properties" />
+        <meta name="assert" content="The 'border-right-style' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                border-right-style: dashed;
+                display: run-in;
+                height: 1in;
+                width: 0;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the line below is dashed.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/border-right-width-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/border-right-width-applies-to-011.xht
new file mode 100644
index 0000000000..b57b4eb0ee
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/border-right-width-applies-to-011.xht
@@ -0,0 +1,24 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Border-right-width applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#propdef-border-right-width" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#border-width-properties" />
+        <meta name="assert" content="The 'border-right-width' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                border-right-style: solid;
+                border-right-width: 1in;
+                display: run-in;
+                height: 1in;
+                width: 0;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a square below.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/border-spacing-applies-to-004.xht b/testing/web-platform/tests/css/css-display/run-in/border-spacing-applies-to-004.xht
new file mode 100644
index 0000000000..ed08262a36
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/border-spacing-applies-to-004.xht
@@ -0,0 +1,25 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Border-spacing and 'display: run-in' elements</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/tables.html#propdef-border-spacing" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/tables.html#separated-borders" />
+        <meta name="assert" content="Border-spacing does not apply to 'display: run-in' elements." />
+        <style type="text/css">
+            div
+            {
+                border: 10px solid black;
+                border-spacing: 20px;
+                display: run-in;
+                height: 100px;
+                width: 100px;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the two boxes below are adjoining.</p>
+        <div></div>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/border-style-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/border-style-applies-to-011.xht
new file mode 100644
index 0000000000..286b75afbd
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/border-style-applies-to-011.xht
@@ -0,0 +1,22 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Border-style applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#border-style-properties" />
+        <meta name="assert" content="The 'border-style' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                border-style: dashed;
+                display: run-in;
+                height: 1in;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a dashed lined box below.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/border-top-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/border-top-applies-to-011.xht
new file mode 100644
index 0000000000..804e76573d
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/border-top-applies-to-011.xht
@@ -0,0 +1,22 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Border-top applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#propdef-border-top" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#border-shorthand-properties" />
+        <meta name="assert" content="The 'border-top' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                border-top: solid green;
+                display: run-in;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a green line below.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/border-top-color-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/border-top-color-applies-to-011.xht
new file mode 100644
index 0000000000..c51329a63d
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/border-top-color-applies-to-011.xht
@@ -0,0 +1,23 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Border-top-color applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#propdef-border-top-color" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#border-color-properties" />
+        <meta name="assert" content="The 'border-top-color' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                border-top-style: solid;
+                border-top-color: green;
+                display: run-in;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the line below is green.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/border-top-style-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/border-top-style-applies-to-011.xht
new file mode 100644
index 0000000000..1b241a4bf6
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/border-top-style-applies-to-011.xht
@@ -0,0 +1,22 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Border-top-style applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#propdef-border-top-style" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#border-style-properties" />
+        <meta name="assert" content="The 'border-top-style' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                border-top-style: dashed;
+                display: run-in;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the line below is dashed.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/border-top-width-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/border-top-width-applies-to-011.xht
new file mode 100644
index 0000000000..575365c980
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/border-top-width-applies-to-011.xht
@@ -0,0 +1,23 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Border-top-width applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#propdef-border-top-width" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#border-width-properties" />
+        <meta name="assert" content="The 'border-top-width' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                border-top-style: solid;
+                border-top-width: 1in;
+                display: run-in;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a square below.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/border-width-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/border-width-applies-to-011.xht
new file mode 100644
index 0000000000..2c4cf3b1cb
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/border-width-applies-to-011.xht
@@ -0,0 +1,24 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Border-width applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#propdef-border-width" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#border-width-properties" />
+        <meta name="assert" content="The 'border-width' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                border-style: solid;
+                border-width: 1in;
+                display: run-in;
+                height: 1in;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a box below with four sides that are the same width. (Note: this will make a large square surrounding a smaller white square.)</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/bottom-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/bottom-applies-to-011.xht
new file mode 100644
index 0000000000..83a7f8fcb4
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/bottom-applies-to-011.xht
@@ -0,0 +1,26 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Bottom applied to element with 'display' set to run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#propdef-bottom" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#dis-pos-flo" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#position-props" />
+        <meta name="assert" content="The 'bottom' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                background: green;
+                bottom: 0;
+                display: run-in;
+                height: 1in;
+                position: absolute;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a box at the bottom of the page.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/caption-side-applies-to-004.xht b/testing/web-platform/tests/css/css-display/run-in/caption-side-applies-to-004.xht
new file mode 100644
index 0000000000..08cc3b1554
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/caption-side-applies-to-004.xht
@@ -0,0 +1,26 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Caption-side and 'display: run-in' elements</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/tables.html#propdef-caption-side" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/tables.html#caption-position" />
+        <meta name="assert" content="Caption-side does not apply to 'display: run-in' elements." />
+        <style type="text/css">
+            span
+            {
+                background: blue;
+                caption-side: bottom;
+                display: run-in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there are three lines of "Filler Text" below and the middle line has a blue background.</p>
+        <div>
+            Filler Text
+            <span>Filler Text</span>
+            Filler Text
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/clear-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/clear-applies-to-011.xht
new file mode 100644
index 0000000000..49eb51d213
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/clear-applies-to-011.xht
@@ -0,0 +1,28 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Clear applied to element with 'display' set to run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#propdef-clear" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#flow-control" />
+        <meta name="assert" content="The 'clear' property applies to elements with a display of 'run-in'." />
+        <style type="text/css">
+            p
+            {
+                float: left;
+            }
+            div
+            {
+                background: green;
+                display: run-in;
+                clear: both;
+                height: 1in;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a box below.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/clear-runin-001.xht b/testing/web-platform/tests/css/css-display/run-in/clear-runin-001.xht
new file mode 100644
index 0000000000..01b6e4c7bf
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/clear-runin-001.xht
@@ -0,0 +1,35 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Clear applies to final block box of a run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#flow-control" />
+        <meta name="assert" content="Clearance only applies to the final block box of a run-in element." />
+        <style type="text/css">
+            #div1
+            {
+                width: 4in;
+            }
+            #span1
+            {
+                background-color: blue;
+                float: left;
+                height: 1in;
+                width: 1in;
+            }
+            #span2
+            {
+                clear: left;
+                display: run-in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the "Filler Text" is all on the same line and is below the blue box.</p>
+        <div id="div1">
+            <span id="span1"></span>
+            <span id="span2">Filler Text </span>
+            <div>Filler Text</div>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/color-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/color-applies-to-011.xht
new file mode 100644
index 0000000000..e8ee1ba832
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/color-applies-to-011.xht
@@ -0,0 +1,23 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Color applied to elements with 'display' set to 'run-in'</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/colors.html#propdef-color" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/colors.html#colors" />
+        <meta name="assert" content="The 'color' property applies to elements with 'display' set to 'run-in'." />
+        <style type="text/css">
+            div
+            {
+                color: green;
+                display: run-in;
+                height: 1in;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the "Filler Text" below is green.</p>
+        <div>Filler Text</div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/counter-increment-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/counter-increment-applies-to-011.xht
new file mode 100644
index 0000000000..73b1c94f4b
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/counter-increment-applies-to-011.xht
@@ -0,0 +1,26 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Counter-increment applied to elements with 'display' set to 'run-in'</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/generate.html#propdef-counter-increment" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/generate.html#counters" />
+        <link rel="match" href="../../reference/pass_if_number_5.xht"/>
+        <meta name="assert" content="The 'counter-increment' property applies to elements with a 'display' set to 'run-in'." />
+        <style type="text/css">
+            div
+            {
+                counter-increment: test 5;
+                display: run-in;
+            }
+            div:before
+            {
+                content: counter(test);
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a number '5' below.</p>
+        <div></div>
+    </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/counter-reset-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/counter-reset-applies-to-011.xht
new file mode 100644
index 0000000000..8038177d70
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/counter-reset-applies-to-011.xht
@@ -0,0 +1,26 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Counter-reset applied to elements with 'display' set to 'run-in'</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/generate.html#propdef-counter-reset" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/generate.html#counters" />
+        <link rel="match" href="../../reference/pass_if_number_5.xht"/>
+        <meta name="assert" content="The 'counter-reset' property applies to elements with a 'display' set to 'run-in'." />
+        <style type="text/css">
+            div
+            {
+                counter-reset: test 5;
+                display: run-in;
+            }
+            div:before
+            {
+                content: counter(test);
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a number '5' below.</p>
+        <div></div>
+    </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/cursor-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/cursor-applies-to-011.xht
new file mode 100644
index 0000000000..d4ed8d2d0c
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/cursor-applies-to-011.xht
@@ -0,0 +1,25 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Cursor applied to element with 'display' set to 'run-in'</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/ui.html#propdef-cursor" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/ui.html#cursor-props" />
+        <meta name="flags" content="interact" />
+        <meta name="assert" content="The 'cursor' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                background-color: blue;
+                cursor: pointer;
+                height: 1in;
+                display: run-in;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the cursor changes to a pointer cursor when it is over the blue area.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/direction-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/direction-applies-to-011.xht
new file mode 100644
index 0000000000..02c4a50b7a
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/direction-applies-to-011.xht
@@ -0,0 +1,27 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Direction applied to element with 'display' set to run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#propdef-direction" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#direction" />
+        <meta name="flags" content="ahem" />
+        <meta name="assert" content="The 'direction' property applies to elements with a display of run-in." />
+        <link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
+        <style type="text/css">
+            div
+            {
+                background: orange;
+                direction: rtl;
+                display: run-in;
+                font: 0.5in/1em Ahem;
+                height: 1in;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a box in the upper-right corner of the orange box.</p>
+        <div>X</div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/display-004.xht b/testing/web-platform/tests/css/css-display/run-in/display-004.xht
new file mode 100644
index 0000000000..8a9ab3225a
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/display-004.xht
@@ -0,0 +1,21 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Display set to 'run-in'</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#propdef-display" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#display-prop" />
+        <meta name="assert" content="The property 'display' set to 'run-in' behaves in layout as a run-in block." />
+        <style type="text/css">
+            #test
+            {
+                display: run-in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the "Filler Text" below is all on the same line.</p>
+        <div id="test">Filler Text</div>
+        <div>Filler Text</div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/empty-cells-applies-to-004.xht b/testing/web-platform/tests/css/css-display/run-in/empty-cells-applies-to-004.xht
new file mode 100644
index 0000000000..8eb74d5daf
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/empty-cells-applies-to-004.xht
@@ -0,0 +1,47 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Empty-cells and 'display: run-in' elements</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/tables.html#propdef-empty-cells" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/tables.html#empty-cells" />
+        <meta name="assert" content="Empty-cells does not apply to 'display: run-in' elements." />
+        <style type="text/css">
+            #table
+            {
+                display: table;
+            }
+            .tr
+            {
+                display: table-row;
+            }
+            .td
+            {
+                color: white;
+                display: table-cell;
+            }
+            #test
+            {
+                background: black;
+                border: 5px solid black;
+                display: run-in;
+                empty-cells: hide;
+                height: 1em;
+                width: 1em;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a box below.</p>
+        <div id="table">
+            <div class="tr">
+                <div id="test"></div>
+                <div class="td">XXXXX</div>
+            </div>
+            <div class="tr">
+                <div class="td">XXXXX</div>
+                <div class="td">XXXXX</div>
+            </div>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/first-line-pseudo-009.xht b/testing/web-platform/tests/css/css-display/run-in/first-line-pseudo-009.xht
new file mode 100644
index 0000000000..690aee9f85
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/first-line-pseudo-009.xht
@@ -0,0 +1,26 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml" lang="en">
+ <head>
+  <title>CSS Test: CSS Block Box Model: first-line and inherited backgrounds</title>
+  <link rel="author" title="Ian Hickson" href="mailto:ian@hixie.ch"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="alternate" href="http://www.hixie.ch/tests/adhoc/css/box/block/first-line/009.html" type="text/html"/>
+  <link rel="help" href="http://www.w3.org/TR/CSS21/selector.html#first-line-pseudo" />
+  <style type="text/css">
+   /* layout */
+   .test { border: solid; margin: 1em; }
+   /* test */
+   .runin { display: run-in; background: navy; color: yellow; }
+   .block { display: block; background: purple; color: white; }
+   .block:first-line { background: inherit; color: inherit; font-weight: bold; }
+   /* control */
+   .fakerunin { display: inline; background: navy; color: yellow; font-weight: bold; }
+   .fakeblock { display: block; background: purple; color: white; font-weight: bold; }
+  </style>
+ </head>
+ <body>
+  <p>The following two lines should look identical (this test also tests run-in).</p>
+  <div class="test"> <div class="runin"> ABC </div> <div class="block"> DEF </div> </div>
+  <div class="test"> <div class="fakeblock"> <div class="fakerunin"> ABC </div> DEF </div> </div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/float-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/float-applies-to-011.xht
new file mode 100644
index 0000000000..4c8933e3ff
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/float-applies-to-011.xht
@@ -0,0 +1,24 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Float applied to element with 'display' set to run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#propdef-float" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#float-position" />
+        <meta name="assert" content="The 'float' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                background: green;
+                display: run-in;
+                float: right;
+                height: 1in;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a box on the right side of the page.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/font-applies-to-004.xht b/testing/web-platform/tests/css/css-display/run-in/font-applies-to-004.xht
new file mode 100644
index 0000000000..3a1864847e
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/font-applies-to-004.xht
@@ -0,0 +1,26 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Font and 'display: run-in' elements</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/fonts.html#propdef-font" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/fonts.html#font-shorthand" />
+        <link rel="help" href="http://www.w3.org/TR/css-fonts-3/#font-prop"/>
+        <meta name="assert" content="The 'font' property applies to 'display: run-in' elements." />
+        <style type="text/css">
+            div
+            {
+                font: italic small-caps bold 16px sans-serif;
+            }
+            #div1
+            {
+                display: run-in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the lines of "Filler Text" below match.</p>
+        <div>Filler Text</div>
+        <div id="div1">Filler Text</div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/font-family-applies-to-004.xht b/testing/web-platform/tests/css/css-display/run-in/font-family-applies-to-004.xht
new file mode 100644
index 0000000000..8895fcb9f8
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/font-family-applies-to-004.xht
@@ -0,0 +1,23 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Font-family and 'display: run-in' elements</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/fonts.html#propdef-font-family" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/fonts.html#font-family-prop" />
+        <meta name="flags" content="ahem" />
+        <meta name="assert" content="The 'font-family' property applies to 'display: run-in' elements." />
+        <link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
+        <style type="text/css">
+            div
+            {
+                display: run-in;
+                font-family: Ahem;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a square below.</p>
+        <div>X</div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/font-size-applies-to-004.xht b/testing/web-platform/tests/css/css-display/run-in/font-size-applies-to-004.xht
new file mode 100644
index 0000000000..143c51742b
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/font-size-applies-to-004.xht
@@ -0,0 +1,32 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Font-size and 'display: run-in' elements</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/fonts.html#propdef-font-size" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/fonts.html#font-size-props" />
+        <link rel="help" href="http://www.w3.org/TR/css-fonts-3/#font-size-prop"/>
+        <meta name="flags" content="ahem" />
+        <meta name="assert" content="The 'font-size' property applies to 'display: run-in' elements." />
+        <link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
+        <style type="text/css">
+            #div1
+            {
+                background: orange;
+                height: 1in;
+                width: 1in;
+            }
+            #div2
+            {
+                display: run-in;
+                font-family: Ahem;
+                font-size: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the boxes below are the same size.</p>
+        <div id="div1"></div>
+        <div id="div2">X</div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/font-style-applies-to-004.xht b/testing/web-platform/tests/css/css-display/run-in/font-style-applies-to-004.xht
new file mode 100644
index 0000000000..449a5c420b
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/font-style-applies-to-004.xht
@@ -0,0 +1,23 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Font-style and 'display: run-in' elements</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/fonts.html#propdef-font-style" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/fonts.html#font-styling" />
+        <link rel="help" href="http://www.w3.org/TR/css-fonts-3/#font-style-prop"/>
+        <link rel="match" href="../../reference/pass_if_filler_text_slanted.xht"/>
+        <meta name="assert" content="The 'font-style' property applies to 'display: run-in' elements." />
+        <style type="text/css">
+            div
+            {
+                display: run-in;
+                font-style: italic;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the "Filler Text" below is slanted to one side.</p>
+        <div>Filler Text</div>
+    </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/font-variant-applies-to-004.xht b/testing/web-platform/tests/css/css-display/run-in/font-variant-applies-to-004.xht
new file mode 100644
index 0000000000..af45082207
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/font-variant-applies-to-004.xht
@@ -0,0 +1,27 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Font-variant and 'display: run-in' elements</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/fonts.html#propdef-font-variant" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/fonts.html#small-caps" />
+        <link rel="help" href="http://www.w3.org/TR/css-fonts-3/#font-variant-prop" />
+        <link rel="match" href="../../reference/pass_if_filler_text_match_smallcaps.xht"/>
+        <meta name="assert" content="The 'font-variant' property applies to 'display: run-in' elements." />
+        <style type="text/css">
+            div
+            {
+                font-variant: small-caps;
+            }
+            #div1
+            {
+                display: run-in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the lines of "Filler Text" below match.</p>
+        <div>Filler Text</div>
+        <div id="div1">Filler Text</div>
+    </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/font-weight-applies-to-004.xht b/testing/web-platform/tests/css/css-display/run-in/font-weight-applies-to-004.xht
new file mode 100644
index 0000000000..bcbf70e3d3
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/font-weight-applies-to-004.xht
@@ -0,0 +1,27 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Font-weight and 'display: run-in' elements</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/fonts.html#propdef-font-weight" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/fonts.html#font-boldness" />
+        <link rel="help" href="http://www.w3.org/TR/css-fonts-3/#font-weight-prop" />
+        <link rel="match" href="../../reference/pass_if_filler_text_match_bold.xht"/>
+        <meta name="assert" content="Font weights apply to 'display: run-in' elements." />
+        <style type="text/css">
+            div
+            {
+                font-weight: bold;
+            }
+            #div1
+            {
+                display: run-in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the lines of "Filler Text" below match.</p>
+        <div>Filler Text</div>
+        <div id="div1">Filler Text</div>
+    </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/height-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/height-applies-to-011.xht
new file mode 100644
index 0000000000..67acc00c79
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/height-applies-to-011.xht
@@ -0,0 +1,24 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Height applied to elements with 'display' set to 'run-in'</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visudet.html#propdef-height" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visudet.html#the-height-property" />
+        <link rel="match" href="../../reference/pass_if_square_96px_black.html"/>
+        <meta name="assert" content="The 'height' property applies to elements with 'display' set to 'run-in'." />
+        <style type="text/css">
+            div
+            {
+                background: black;
+                display: run-in;
+                height: 1in;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a square below.</p>
+        <div></div>
+    </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/left-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/left-applies-to-011.xht
new file mode 100644
index 0000000000..604877974e
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/left-applies-to-011.xht
@@ -0,0 +1,26 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Left applied to element with 'display' set to run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#propdef-left" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#dis-pos-flo" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#position-props" />
+        <meta name="assert" content="The 'left' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                background: green;
+                left: 0;
+                display: run-in;
+                height: 1in;
+                position: absolute;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a box on the left side of the page.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/letter-spacing-applies-to-004.xht b/testing/web-platform/tests/css/css-display/run-in/letter-spacing-applies-to-004.xht
new file mode 100644
index 0000000000..33c71fbcb1
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/letter-spacing-applies-to-004.xht
@@ -0,0 +1,37 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Letter-spacing application on a 'display: run-in' element</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/text.html#propdef-letter-spacing" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/text.html#spacing-props" />
+        <link rel="match" href="../../reference/black_box_ends_when_blue_box_ends_6_boxes_ahem.html"/>
+        <meta name="flags" content="ahem" />
+        <meta name="assert" content="The 'letter-spacing' property is applied to 'display: run-in' elements." />
+        <link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
+        <style type="text/css">
+            div
+            {
+                font: 16px/1em Ahem;
+            }
+            div div
+            {
+                display: run-in;
+                letter-spacing: 1em;
+            }
+            #div1
+            {
+                background: blue;
+                height: 1em;
+                width: 11em;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there are six black boxes below and the last black box ends when the blue box ends.</p>
+        <div>
+            <div>XXXXXX</div>
+        </div>
+        <div id="div1"></div>
+    </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/line-height-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/line-height-applies-to-011.xht
new file mode 100644
index 0000000000..b8ddd08618
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/line-height-applies-to-011.xht
@@ -0,0 +1,39 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Line-height applied to elements with 'display' set to 'run-in'</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visudet.html#propdef-line-height" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visudet.html#leading" />
+        <meta name="assert" content="The 'line-height' property applies to elements with 'display' set to 'run-in'." />
+        <style type="text/css">
+            #div1
+            {
+                position: relative;
+            }
+            #div2
+            {
+                background: blue;
+                display: run-in;
+                line-height: 2in;
+                width: 1in;
+            }
+            #div3
+            {
+                background: orange;
+                height: 2in;
+                left: 1in;
+                position: absolute;
+                top: 0;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the blue and orange boxes below are the same height.</p>
+        <div id="div1">
+            <div id="div2">&nbsp;</div>
+            <div id="div3"></div>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/list-style-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/list-style-applies-to-011.xht
new file mode 100644
index 0000000000..4b0a0e46ce
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/list-style-applies-to-011.xht
@@ -0,0 +1,29 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: List-style applied to elements with 'display' set to 'run-in'</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/generate.html#propdef-list-style" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/generate.html#list-style" />
+        <link rel="match" href="../../reference/single_square_list_marker.xht"/>
+        <meta name="assert" content="The 'list-style' property applies to elements with 'display' set to 'run-in'." />
+        <style type="text/css">
+            div
+            {
+                display: run-in;
+                list-style: square;
+                margin-left: 1in;
+            }
+            span
+            {
+                display: list-item;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a single square below.</p>
+        <div>
+            <span></span>
+        </div>
+    </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/list-style-image-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/list-style-image-applies-to-011.xht
new file mode 100644
index 0000000000..dca032c6e9
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/list-style-image-applies-to-011.xht
@@ -0,0 +1,29 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: List-style-image applied to elements with 'display' set to 'run-in'</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/generate.html#propdef-list-style-image" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/generate.html#list-style" />
+        <meta name="flags" content="image" />
+        <meta name="assert" content="The 'list-style-image' property applies to elements with 'display' set to 'run-in'." />
+        <style type="text/css">
+            div
+            {
+                display: run-in;
+                list-style-image: url('support/blue15x15.png');
+                margin-left: 1in;
+            }
+            span
+            {
+                display: list-item;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a single blue square below.</p>
+        <div>
+            <span></span>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/list-style-position-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/list-style-position-applies-to-011.xht
new file mode 100644
index 0000000000..e38e4f3e1d
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/list-style-position-applies-to-011.xht
@@ -0,0 +1,29 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: List-style-position applied to elements with 'display' set to 'run-in'</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/generate.html#propdef-list-style-position" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/generate.html#list-style" />
+        <meta name="assert" content="The 'list-style-position' property applies to elements with 'display' set to 'run-in'." />
+        <style type="text/css">
+            div
+            {
+                display: run-in;
+                list-style-position: inside;
+                margin-left: 1in;
+            }
+            span
+            {
+                background: orange;
+                display: list-item;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a black dot inside an orange box below.</p>
+        <div>
+            <span></span>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/list-style-type-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/list-style-type-applies-to-011.xht
new file mode 100644
index 0000000000..fed66d951f
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/list-style-type-applies-to-011.xht
@@ -0,0 +1,29 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: List-style-type applied to elements with 'display' set to 'run-in'</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/generate.html#propdef-list-style-type" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/generate.html#list-style" />
+        <link rel="match" href="../../reference/single_square_list_marker.xht"/>
+        <meta name="assert" content="The 'list-style-type' property applies to elements with 'display' set to 'run-in'." />
+        <style type="text/css">
+            div
+            {
+                display: run-in;
+                list-style-type: square;
+                margin-left: 1in;
+            }
+            span
+            {
+                display: list-item;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a single square below.</p>
+        <div>
+            <span></span>
+        </div>
+    </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/margin-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/margin-applies-to-011.xht
new file mode 100644
index 0000000000..4282f3e7fc
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/margin-applies-to-011.xht
@@ -0,0 +1,31 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Margin applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#propdef-margin" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#margin-properties" />
+        <meta name="assert" content="The 'Margin' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            #wrapper
+            {
+                border: 10px solid blue;
+                position: absolute;
+            }
+            #test
+            {
+                border: 10px solid orange;
+                display: run-in;
+                height: 200px;
+                width: 200px;
+                margin: 50px;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is space between the blue and orange lines below.</p>
+        <div id="wrapper">
+            <div id="test"></div>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/margin-bottom-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/margin-bottom-applies-to-011.xht
new file mode 100644
index 0000000000..38d6498c45
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/margin-bottom-applies-to-011.xht
@@ -0,0 +1,30 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Margin-bottom applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#propdef-margin-bottom" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#margin-properties" />
+        <meta name="assert" content="The 'margin-bottom' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            #wrapper
+            {
+                border-bottom: 10px solid blue;
+            }
+            div div
+            {
+                border-bottom: 10px solid orange;
+                display: run-in;
+                height: 200px;
+                margin-bottom: 50px;
+                width: 200px;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is space between the blue and orange lines below.</p>
+        <div id="wrapper">
+            <div></div>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/margin-left-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/margin-left-applies-to-011.xht
new file mode 100644
index 0000000000..906e95cb32
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/margin-left-applies-to-011.xht
@@ -0,0 +1,33 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Margin-left applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#propdef-margin-left" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#margin-properties" />
+        <meta name="assert" content="The 'margin-left' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                height: 200px;
+                width: 200px;
+            }
+            #div1
+            {
+                border-left: 10px solid blue;
+            }
+            div div
+            {
+                border-left: 10px solid orange;
+                display: run-in;
+                margin-left: 50px;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is space between the blue and orange lines below.</p>
+        <div id="div1">
+            <div></div>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/margin-right-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/margin-right-applies-to-011.xht
new file mode 100644
index 0000000000..ee1c80dfd2
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/margin-right-applies-to-011.xht
@@ -0,0 +1,33 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Margin-right applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#propdef-margin-right" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#margin-properties" />
+        <meta name="assert" content="The 'margin-right' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                height: 200px;
+            }
+            #div1
+            {
+                border-right: 10px solid blue;
+                width: 200px;
+            }
+            div div
+            {
+                border-right: 10px solid orange;
+                display: run-in;
+                margin-right: 50px;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is space between the blue and orange lines below.</p>
+        <div id="div1">
+            <div></div>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/margin-top-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/margin-top-applies-to-011.xht
new file mode 100644
index 0000000000..95af9e8ccd
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/margin-top-applies-to-011.xht
@@ -0,0 +1,33 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Margin-top applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#propdef-margin-top" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#margin-properties" />
+        <meta name="assert" content="The 'margin-top' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                height: 200px;
+                width: 200px;
+            }
+            #div1
+            {
+                border-top: 10px solid blue;
+            }
+            div div
+            {
+                border-top: 10px solid orange;
+                display: run-in;
+                margin-top: 50px;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is space between the blue and orange lines below.</p>
+        <div id="div1">
+            <div></div>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/max-height-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/max-height-applies-to-011.xht
new file mode 100644
index 0000000000..f27561c182
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/max-height-applies-to-011.xht
@@ -0,0 +1,25 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Max-height applied to elements with 'display' set to 'run-in'</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visudet.html#propdef-max-height" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visudet.html#min-max-heights" />
+        <link rel="match" href="../../reference/pass_if_square_96px_black.html"/>
+        <meta name="assert" content="The 'max-height' property applies to elements with 'display' set to 'run-in'." />
+        <style type="text/css">
+            div
+            {
+                background: black;
+                display: run-in;
+                height: 3in;
+                max-height: 1in;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a square below.</p>
+        <div></div>
+    </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/max-width-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/max-width-applies-to-011.xht
new file mode 100644
index 0000000000..65337647e0
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/max-width-applies-to-011.xht
@@ -0,0 +1,25 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Max-width applied to elements with 'display' set to 'run-in'</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visudet.html#propdef-max-width" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visudet.html#min-max-widths" />
+        <link rel="match" href="../../reference/pass_if_square_96px_black.html"/>
+        <meta name="assert" content="The 'max-width' property applies to elements with 'display' set to 'run-in'." />
+        <style type="text/css">
+            div
+            {
+                background: black;
+                display: run-in;
+                height: 1in;
+                max-width: 1in;
+                width: 3in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a square below.</p>
+        <div></div>
+    </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/min-height-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/min-height-applies-to-011.xht
new file mode 100644
index 0000000000..ca2a6ba0fa
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/min-height-applies-to-011.xht
@@ -0,0 +1,24 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Min-height applied to elements with 'display' set to 'run-in'</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visudet.html#propdef-min-height" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visudet.html#min-max-heights" />
+        <link rel="match" href="../../reference/pass_if_square_96px_black.html"/>
+        <meta name="assert" content="The 'min-height' property applies to elements with 'display' set to 'run-in'." />
+        <style type="text/css">
+            div
+            {
+                background: black;
+                display: run-in;
+                min-height: 1in;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a square below.</p>
+        <div></div>
+    </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/min-width-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/min-width-applies-to-011.xht
new file mode 100644
index 0000000000..b905bf9383
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/min-width-applies-to-011.xht
@@ -0,0 +1,30 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Min-width applied to elements with 'display' set to 'run-in'</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visudet.html#propdef-min-width" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visudet.html#min-max-widths" />
+        <link rel="match" href="../../reference/pass_if_square_96px_black.html"/>
+        <meta name="assert" content="The 'min-width' property applies to elements with 'display' set to 'run-in'." />
+        <style type="text/css">
+            #div1
+            {
+                width: 0.5in;
+            }
+            div div
+            {
+                background: black;
+                display: run-in;
+                height: 1in;
+                min-width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a square below.</p>
+        <div id="div1">
+            <div></div>
+        </div>
+    </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/outline-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/outline-applies-to-011.xht
new file mode 100644
index 0000000000..98da6983da
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/outline-applies-to-011.xht
@@ -0,0 +1,23 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Outline applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/ui.html#propdef-outline" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/ui.html#dynamic-outlines" />
+        <meta name="assert" content="The 'outline' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                display: run-in;
+                height: 1in;
+                outline: solid blue 10px;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a blue box below.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/outline-color-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/outline-color-applies-to-011.xht
new file mode 100644
index 0000000000..1012b5d0ba
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/outline-color-applies-to-011.xht
@@ -0,0 +1,25 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Outline-color applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/ui.html#propdef-outline-color" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/ui.html#dynamic-outlines" />
+        <meta name="assert" content="The 'outline-color' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                height: 1in;
+                display: run-in;
+                outline-color: blue;
+                outline-style: solid;
+                outline-width: 10px;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the box below is blue.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/outline-style-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/outline-style-applies-to-011.xht
new file mode 100644
index 0000000000..934aee6246
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/outline-style-applies-to-011.xht
@@ -0,0 +1,25 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Outline-style applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/ui.html#propdef-outline-style" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/ui.html#dynamic-outlines" />
+        <meta name="assert" content="The 'outline-style' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                display: run-in;
+                height: 1in;
+                outline-color: blue;
+                outline-style: dotted;
+                outline-width: 10px;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the box below has a dotted border.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/outline-width-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/outline-width-applies-to-011.xht
new file mode 100644
index 0000000000..216dd8c62c
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/outline-width-applies-to-011.xht
@@ -0,0 +1,25 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Outline-width applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/ui.html#propdef-outline-width" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/ui.html#dynamic-outlines" />
+        <meta name="assert" content="The 'outline-width' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                display: run-in;
+                height: 1in;
+                outline-color: green;
+                outline-style: solid;
+                outline-width: 10px;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a green box below.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/overflow-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/overflow-applies-to-011.xht
new file mode 100644
index 0000000000..bbf47e3bb2
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/overflow-applies-to-011.xht
@@ -0,0 +1,32 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: overflow applied to elements with 'display' set to 'run-in'</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visufx.html#propdef-overflow" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visufx.html#overflow" />
+        <meta name="flags" content="ahem" />
+        <meta name="assert" content="The 'overflow' property applies to elements with 'display' set to 'run-in'." />
+        <link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
+        <style type="text/css">
+            div
+            {
+                border: 5px solid transparent;
+                color: white;
+                display: run-in;
+                font: 20px/1em Ahem;
+                height: 5em;
+                overflow: hidden;
+                width: 5em;
+            }
+            #span2
+            {
+                color: red;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is no red visible on the page.</p>
+        <div><span>XXXXX</span><span id="span2">XXXXX</span></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/padding-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/padding-applies-to-011.xht
new file mode 100644
index 0000000000..58567c7b28
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/padding-applies-to-011.xht
@@ -0,0 +1,30 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Padding applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#propdef-padding" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#padding-properties" />
+        <meta name="assert" content="The 'padding' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            #div1
+            {
+                border: 10px solid blue;
+                display: run-in;
+                padding: 50px;
+                width: 200px;
+            }
+            div div
+            {
+                border: 10px solid orange;
+                height: 200px;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is space between the blue and orange lines on all four sides.</p>
+        <div id="div1">
+            <div></div>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/padding-bottom-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/padding-bottom-applies-to-011.xht
new file mode 100644
index 0000000000..c31cfb2ca2
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/padding-bottom-applies-to-011.xht
@@ -0,0 +1,32 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Padding-bottom applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#propdef-padding-bottom" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#padding-properties" />
+        <meta name="assert" content="The 'padding-bottom' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                width: 200px;
+            }
+            #div1
+            {
+                border-bottom: 10px solid blue;
+                display: run-in;
+                padding-bottom: 50px;
+            }
+            div div
+            {
+                border-bottom: 10px solid orange;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is space between the blue and orange lines below.</p>
+        <div id="div1">
+            <div></div>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/padding-left-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/padding-left-applies-to-011.xht
new file mode 100644
index 0000000000..5c2eb7aaf0
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/padding-left-applies-to-011.xht
@@ -0,0 +1,33 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Padding-left applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#propdef-padding-left" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#padding-properties" />
+        <meta name="assert" content="The 'padding-left' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                height: 200px;
+                width: 200px;
+            }
+            #div1
+            {
+                border-left: 10px solid blue;
+                display: run-in;
+                padding-left: 50px;
+            }
+            div div
+            {
+                border-left: 10px solid orange;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is space between the blue and orange lines below.</p>
+        <div id="div1">
+            <div></div>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/padding-right-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/padding-right-applies-to-011.xht
new file mode 100644
index 0000000000..25d09ff02f
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/padding-right-applies-to-011.xht
@@ -0,0 +1,33 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Padding-right applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#propdef-padding-right" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#padding-properties" />
+        <meta name="assert" content="The 'padding-right' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                height: 200px;
+            }
+            #div1
+            {
+                border-right: 10px solid blue;
+                display: run-in;
+                padding-right: 50px;
+                width: 200px;
+            }
+            div div
+            {
+                border-right: 10px solid orange;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is space between the blue and orange lines below.</p>
+        <div id="div1">
+            <div></div>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/padding-top-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/padding-top-applies-to-011.xht
new file mode 100644
index 0000000000..5cce439be6
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/padding-top-applies-to-011.xht
@@ -0,0 +1,32 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Padding-top applied to element with display run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#propdef-padding-top" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/box.html#padding-properties" />
+        <meta name="assert" content="The 'padding-top' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                width: 200px;
+            }
+            #div1
+            {
+                border-top: 10px solid blue;
+                display: run-in;
+                padding-top: 50px;
+            }
+            div div
+            {
+                border-top: 10px solid orange;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is space between the blue and orange lines below.</p>
+        <div id="div1">
+            <div></div>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/position-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/position-applies-to-011.xht
new file mode 100644
index 0000000000..6e683b255d
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/position-applies-to-011.xht
@@ -0,0 +1,26 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Position applied to element with 'display' set to run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#propdef-position" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#dis-pos-flo" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#choose-position" />
+        <meta name="assert" content="The 'position' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                background: green;
+                bottom: 0;
+                display: run-in;
+                height: 1in;
+                position: absolute;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a box at the bottom of the page.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/quotes-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/quotes-applies-to-011.xht
new file mode 100644
index 0000000000..9594507359
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/quotes-applies-to-011.xht
@@ -0,0 +1,26 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Quotes applied to elements with 'display' set to 'run-in'</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/generate.html#propdef-quotes" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/generate.html#quotes-specify" />
+        <link rel="match" href="../../reference/pass_if_pass_below.html" />
+        <meta name="assert" content="The 'quotes' property applies to elements with a 'display' set to 'run-in'." />
+        <style type="text/css">
+            div
+            {
+                display: run-in;
+                quotes: "P" "S" "A" "S";
+            }
+            div:before
+            {
+                content: open-quote open-quote close-quote close-quote;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is the word "PASS" below.</p>
+        <div></div>
+    </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/right-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/right-applies-to-011.xht
new file mode 100644
index 0000000000..59af50fe68
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/right-applies-to-011.xht
@@ -0,0 +1,26 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Right applied to element with 'display' set to run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#propdef-right" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#dis-pos-flo" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#position-props" />
+        <meta name="assert" content="The 'right' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                background: green;
+                right: 0;
+                display: run-in;
+                height: 1in;
+                position: absolute;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a box on the right side of the page.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-001.xht
new file mode 100644
index 0000000000..d16fc20e01
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-001.xht
@@ -0,0 +1,35 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Run-in with a block box converts to a block box</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in" />
+        <meta name="flags" content="ahem" />
+        <meta name="assert" content="Run-in boxes are converted to block boxes when the run-in box contains a block box." />
+        <link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
+        <style type="text/css">
+            div
+            {
+                font: 20px/1em Ahem;
+            }
+            #span1
+            {
+                display: run-in;
+            }
+            span span
+            {
+                display: block;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a square below.</p>
+        <div>
+            <span>XXX</span>
+            <span id="span1">
+                XXX
+                <span>XXX</span>
+            </span>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-002.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-002.xht
new file mode 100644
index 0000000000..6541659627
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-002.xht
@@ -0,0 +1,27 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Run-in boxes change to inline boxes</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in" />
+        <meta name="assert" content="Sibling block boxes following a run-in makes the run-in become an inline of the block box." />
+        <style type="text/css">
+            #span1
+            {
+                display: run-in;
+            }
+            #span2
+            {
+                background: orange;
+                display: block;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the "Filler Text" below is all on the same line and is completely contained within the orange box.</p>
+        <div>
+            <span id="span1">Filler Text</span>
+            <span id="span2">Filler Text</span>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-003.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-003.xht
new file mode 100644
index 0000000000..2a6d75eb1f
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-003.xht
@@ -0,0 +1,33 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Run-in boxes and float</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in" />
+        <meta name="flags" content="ahem" />
+        <meta name="assert" content="Float prevents run-in from becoming inline." />
+        <link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
+        <style type="text/css">
+            span
+            {
+                font: 20px/1em Ahem;
+            }
+            #span1
+            {
+                display: run-in;
+            }
+            #span2
+            {
+                display: block;
+                float: left;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a square below.</p>
+        <div>
+            <span id="span1">XX</span>
+            <span id="span2">XX</span>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-004.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-004.xht
new file mode 100644
index 0000000000..e19688b2ae
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-004.xht
@@ -0,0 +1,33 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Run-in boxes and absolute positioning</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in" />
+        <meta name="flags" content="ahem" />
+        <meta name="assert" content="Absolute positioning prevents run-in from becoming inline." />
+        <link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
+        <style type="text/css">
+            span
+            {
+                font: 20px/1em Ahem;
+            }
+            #span1
+            {
+                display: run-in;
+            }
+            #span2
+            {
+                display: block;
+                position: absolute;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a square below.</p>
+        <div>
+            <span id="span1">XX</span>
+            <span id="span2">XX</span>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-005.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-005.xht
new file mode 100644
index 0000000000..b16506f363
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-005.xht
@@ -0,0 +1,29 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Run-in that starts with a run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in" />
+        <meta name="assert" content="Run-in boxes cannot run-in with another box that already starts with a run-in." />
+        <style type="text/css">
+            span
+            {
+                display: run-in;
+            }
+            span span
+            {
+                background: orange;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if words "Filler Text" are on three separate lines and the orange box in the middle spans the entire width of the page.</p>
+        <div>
+            <span id="span1">
+                Filler Text
+                <span>Filler Text</span>
+                Filler Text
+            </span>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-006.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-006.xht
new file mode 100644
index 0000000000..55a80fed06
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-006.xht
@@ -0,0 +1,33 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Run-in with a table box</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#propdef-display" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#display-prop" />
+        <meta name="flags" content="ahem" />
+        <meta name="assert" content="Run-in boxes are converted to block boxes when the run-in box runs into a table box." />
+        <link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
+        <style type="text/css">
+            span
+            {
+                font: 20px/1em Ahem;
+            }
+            #span1
+            {
+                display: run-in;
+            }
+            #span2
+            {
+                display: table;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a square below.</p>
+        <div>
+            <span id="span1">XX</span>
+            <span id="span2">XX</span>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-007.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-007.xht
new file mode 100644
index 0000000000..e24242a9a7
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-007.xht
@@ -0,0 +1,33 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Run-in with a inline-table box</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#propdef-display" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#display-prop" />
+        <meta name="flags" content="ahem" />
+        <meta name="assert" content="Run-in boxes are converted to block boxes when the run-in box runs into an inline-table box." />
+        <link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
+        <style type="text/css">
+            span
+            {
+                font: 20px/1em Ahem;
+            }
+            #span1
+            {
+                display: run-in;
+            }
+            #span2
+            {
+                display: inline-table;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a square below.</p>
+        <div>
+            <span id="span1">XX</span>
+            <span id="span2">XX</span>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-008.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-008.xht
new file mode 100644
index 0000000000..87ca7073bd
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-008.xht
@@ -0,0 +1,33 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Run-in with a table-row-group box</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#propdef-display" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#display-prop" />
+        <meta name="flags" content="ahem" />
+        <meta name="assert" content="Run-in boxes are converted to block boxes when the run-in box runs into a table-row-group box." />
+        <link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
+        <style type="text/css">
+            span
+            {
+                font: 20px/1em Ahem;
+            }
+            #span1
+            {
+                display: run-in;
+            }
+            #span2
+            {
+                display: table-row-group;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a square below.</p>
+        <div>
+            <span id="span1">XX</span>
+            <span id="span2">XX</span>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-009.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-009.xht
new file mode 100644
index 0000000000..255dfa0ae7
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-009.xht
@@ -0,0 +1,33 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Run-in with a table-row box</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#propdef-display" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#display-prop" />
+        <meta name="flags" content="ahem" />
+        <meta name="assert" content="Run-in boxes are converted to block boxes when the run-in box runs into a table-row box." />
+        <link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
+        <style type="text/css">
+            span
+            {
+                font: 20px/1em Ahem;
+            }
+            #span1
+            {
+                display: run-in;
+            }
+            #span2
+            {
+                display: table-row;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a square below.</p>
+        <div>
+            <span id="span1">XX</span>
+            <span id="span2">XX</span>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-010.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-010.xht
new file mode 100644
index 0000000000..4f1738cc1d
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-010.xht
@@ -0,0 +1,33 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Run-in with a table-cell box</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#propdef-display" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#display-prop" />
+        <meta name="flags" content="ahem" />
+        <meta name="assert" content="Run-in boxes are converted to block boxes when the run-in box runs into a table-cell box." />
+        <link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
+        <style type="text/css">
+            span
+            {
+                font: 20px/1em Ahem;
+            }
+            #span1
+            {
+                display: run-in;
+            }
+            #span2
+            {
+                display: table-cell;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a square below.</p>
+        <div>
+            <span id="span1">XX</span>
+            <span id="span2">XX</span>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-011.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-011.xht
new file mode 100644
index 0000000000..5e45d90e42
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-011.xht
@@ -0,0 +1,33 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Run-in with a table-caption box</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#propdef-display" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#display-prop" />
+        <meta name="flags" content="ahem" />
+        <meta name="assert" content="Run-in boxes are converted to block boxes when the run-in box runs into a table-caption box." />
+        <link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
+        <style type="text/css">
+            span
+            {
+                font: 20px/1em Ahem;
+            }
+            #span1
+            {
+                display: run-in;
+            }
+            #span2
+            {
+                display: table-caption;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a square below.</p>
+        <div>
+            <span id="span1">XX</span>
+            <span id="span2">XX</span>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-012.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-012.xht
new file mode 100644
index 0000000000..0673437b72
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-012.xht
@@ -0,0 +1,33 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Run-in with a table-header-group box</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#propdef-display" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#display-prop" />
+        <meta name="flags" content="ahem" />
+        <meta name="assert" content="Run-in boxes are converted to block boxes when the run-in box runs into a table-header-group box." />
+        <link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
+        <style type="text/css">
+            span
+            {
+                font: 20px/1em Ahem;
+            }
+            #span1
+            {
+                display: run-in;
+            }
+            #span2
+            {
+                display: table-header-group;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a square below.</p>
+        <div>
+            <span id="span1">XX</span>
+            <span id="span2">XX</span>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-013.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-013.xht
new file mode 100644
index 0000000000..0102222b35
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-013.xht
@@ -0,0 +1,34 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Run-in with a table-footer-group box</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#propdef-display" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#display-prop" />
+        <meta name="flags" content="ahem" />
+        <meta name="assert" content="Run-in boxes are converted to block boxes when the run-in box runs into a table-footer-group box." />
+        <link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
+        <style type="text/css">
+            span
+            {
+                font: 20px/1em Ahem;
+            }
+            #span1
+            {
+                display: run-in;
+            }
+            #span2
+            {
+                display: table-footer-group;
+                background: blue;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a square below.</p>
+        <div>
+            <span id="span1">XX</span>
+            <span id="span2">XX</span>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-abspos-between-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-abspos-between-001.xht
new file mode 100644
index 0000000000..1af8ee4567
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-abspos-between-001.xht
@@ -0,0 +1,24 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - abs pos should not prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins actually run in if there is an absolutely
+                 positioned element between the run-in and the following block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    .abspos { position: absolute; visibility: hidden; }
+    #target { border: 2px solid black; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div class="abspos"></div>
+   <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-abspos-between-002.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-abspos-between-002.xht
new file mode 100644
index 0000000000..8303df2bf6
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-abspos-between-002.xht
@@ -0,0 +1,40 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - block set to abs pos should allow running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins run in if a block is dynamically set to
+                 absolutely positioned between them and the following block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    .abspos { position: absolute; visibility: hidden; }
+    #target { border: 2px solid black; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var r = document.getElementById("r");
+      r.className = "abspos";
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="r">Some text.</div>
+   <div id="target">Start of block.  The run-in header should be inside the
+    border around this block and there should be no space between the word
+    "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-abspos-between-003.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-abspos-between-003.xht
new file mode 100644
index 0000000000..5053a7a5ea
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-abspos-between-003.xht
@@ -0,0 +1,40 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - inline toggled from abs pos should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins don't run in if an inline between them and
+                 the block is toggled from being absolutely positioned."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    .abspos { position: absolute; visibility: hidden; }
+    #target { border: 2px solid black; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var r = document.getElementById("r");
+      r.className = "";
+    }
+  ]]></script>
+ </head>
+ <body>
+  <div>
+     <div class="run-in">Run-in header</div>
+     <span id="r" class="abspos">Some text.</span>
+     <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+  </div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-basic-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-001.xht
new file mode 100644
index 0000000000..d28a657595
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-001.xht
@@ -0,0 +1,23 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - basic functionality</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="assert"
+        content="Run-ins run into a following block if there is nothing
+                 between the run-in and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div><div id="target">Start of block.  The
+   run-in header should be inside the border around this block and there should
+   be no space between the word "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-basic-002.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-002.xht
new file mode 100644
index 0000000000..6c7b7c3c9e
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-002.xht
@@ -0,0 +1,22 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - basic functionality with whitespace</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="assert"
+        content="Run-ins run into a following block if there is collapsed
+                 whitespace between the run-in and the following block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-basic-003.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-003.xht
new file mode 100644
index 0000000000..16121978c3
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-003.xht
@@ -0,0 +1,25 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - basic functionality with comments</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="assert"
+        content="Run-ins run into a following block if there is collapsed
+                 whitespace and comments between the run-in and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <!-- This is a comment -->
+
+   <!-- And another comment -->
+   <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-basic-004.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-004.xht
new file mode 100644
index 0000000000..faad2521e2
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-004.xht
@@ -0,0 +1,36 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - basic functionality with multiple whitespace nodes</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins actually run in if there are multiple
+                 whitespace nodes between the run-in and the following block.
+                 There must be multiple whitespace nodes in the DOM between the
+                 run-in and the following block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+  ]]></style>
+ </head>
+ <body>
+   <div id="makemerun">Run-in header</div>
+   <script type="text/javascript"><![CDATA[
+     document.body.appendChild(document.createTextNode("  "));
+     document.body.appendChild(document.createTextNode("  "));
+     window.onload = function() {
+       var t = document.getElementById("target");
+       if (t.previousSibling.nodeType == 3 /* Node.TEXT_NODE */ &&
+           t.previousSibling.previousSibling.nodeType == 3) {
+         document.getElementById("makemerun").className = "run-in";
+       }
+     }
+   ]]></script>
+   <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-basic-005.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-005.xht
new file mode 100644
index 0000000000..47c7632bbb
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-005.xht
@@ -0,0 +1,23 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - basic functionality with following block containing run-in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-block-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins actually run in if the following block has
+                 a display:run-in child."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    #target > div { display: run-in; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="target"><div>Start of block.  The run-in header should be inside the border around this block and there should be a newline between the word "header" and the word "Start".</div></div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-basic-006.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-006.xht
new file mode 100644
index 0000000000..d77b02a001
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-006.xht
@@ -0,0 +1,21 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - basic functionality with list-item</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins actually run in if followed by a list-item."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; display: list-item; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-basic-007-ref.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-007-ref.xht
new file mode 100644
index 0000000000..ba04ce3435
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-007-ref.xht
@@ -0,0 +1,17 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+  <head>
+    <title>CSS Reftest Reference</title>
+    <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+    <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+    <style type="text/css">
+      .run-in { font-weight: bold }
+      #target { border: 2px solid black; overflow: scroll; }
+    </style>
+  </head>
+  <body>
+    <div id="target"><span class="run-in">Run-in header</span>Start of block.
+    The run-in header should be inside the border around this block and there
+    should be no space between the word "header" and the word "Start".</div>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-basic-007.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-007.xht
new file mode 100644
index 0000000000..4138a9f697
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-007.xht
@@ -0,0 +1,22 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - runs into overflow:scroll block</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-007-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins actually run in if the block has
+                 overflow:scroll."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; overflow: scroll; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-basic-008.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-008.xht
new file mode 100644
index 0000000000..412eec6786
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-008.xht
@@ -0,0 +1,25 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - runs into relatively positioned block</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins actually run in if the block is relatively
+                 positioned."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; position: relative; top: 2em; left: 2em; }
+    #container { position: relative; top: -2em; left: -2em; }
+  ]]></style>
+ </head>
+ <body>
+   <div id="container">
+     <div class="run-in">Run-in header</div>
+     <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+   </div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-basic-009.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-009.xht
new file mode 100644
index 0000000000..14c997804d
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-009.xht
@@ -0,0 +1,22 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - run-ins run in even if given overflow:scroll</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins actually run in if they have
+                 overflow:scroll set."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold; overflow: scroll }
+    #target { border: 2px solid black; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-basic-010.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-010.xht
new file mode 100644
index 0000000000..2dc30223e6
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-010.xht
@@ -0,0 +1,23 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - parsing a block after a run-in should make the run-in run in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins actually run in if a block is parsed after them."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <script type="text/javascript">document.body.offsetHeight; /* flush layout here on purpose */</script>
+   <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-basic-011.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-011.xht
new file mode 100644
index 0000000000..afc85413af
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-011.xht
@@ -0,0 +1,36 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - inserting a block after a run-in should make the run-in run in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins actually run in if a block is inserted after them."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var t = document.createElement("div");
+      t.id = "target";
+      t.appendChild(document.createTextNode('Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".'));
+      document.body.appendChild(t);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-basic-012.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-012.xht
new file mode 100644
index 0000000000..c5d35bf236
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-012.xht
@@ -0,0 +1,23 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - basic functionality with :before</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins end up before :before content when they run
+                 in."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    #target:before { content: "Start of block.  " }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="target">The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-basic-013.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-013.xht
new file mode 100644
index 0000000000..af810ac289
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-013.xht
@@ -0,0 +1,37 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically inserted run-in should run in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that dynamically inserted run-ins run in."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var t = document.getElementById("target");
+      var s = document.createElement("div");
+      s.appendChild(document.createTextNode("Run-in header"));
+      s.className = "run-in";
+      t.parentNode.insertBefore(s, t);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-basic-014.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-014.xht
new file mode 100644
index 0000000000..9f52e92cec
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-014.xht
@@ -0,0 +1,22 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - basic functionality with preserved whitespace</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-pre-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins don't run in across preserved whitespace."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    #container { white-space: pre; }
+    #container > * { white-space: normal; }
+  ]]></style>
+ </head>
+ <body>
+   <div id="container"><div class="run-in">Run-in header</div> <div id="target">Start of block. The run-in header should be outside the border around this block and there should be a blank line between the run-in header and this block.</div></div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-basic-015.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-015.xht
new file mode 100644
index 0000000000..8eee5e98df
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-015.xht
@@ -0,0 +1,37 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically preserved whitespace</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-pre-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins don't run in across preserved whitespace
+                 even if it's preserved dynamically."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    .container { white-space: pre; }
+    .container > * { white-space: normal; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var c = document.getElementById("container");
+      c.className = "container";
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div id="container"><div class="run-in">Run-in header</div> <div id="target">Start of block. The run-in header should be outside the border around this block and there should be a blank line between the run-in header and this block.</div></div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-basic-016.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-016.xht
new file mode 100644
index 0000000000..4e8d71ae89
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-016.xht
@@ -0,0 +1,37 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically added preserved whitespace(2)</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-pre-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins don't run in across preserved whitespace
+                 even if it's added dynamically."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    #container { white-space: pre; }
+    #container > * { white-space: normal; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var t = document.getElementById("target");
+      t.parentNode.insertBefore(document.createTextNode(" "), t);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div id="container"><div class="run-in">Run-in header</div><div id="target">Start of block. The run-in header should be outside the border around this block and there should be a blank line between the run-in header and this block.</div></div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-basic-017.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-017.xht
new file mode 100644
index 0000000000..065fe751f3
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-017.xht
@@ -0,0 +1,40 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically added preserved whitespace(3)</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-pre-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins don't run in across preserved whitespace
+                 even if it's added dynamically."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    #container { white-space: pre; }
+    #container > * { white-space: normal; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var t = document.getElementById("target");
+      var s = document.createTextNode("");
+      t.parentNode.insertBefore(s, t);
+      flushLayout(document.documentElement);
+      s.data = " ";
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div id="container"><div class="run-in">Run-in header</div><div id="target">Start of block. The run-in header should be outside the border around this block and there should be a blank line between the run-in header and this block.</div></div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-basic-018.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-018.xht
new file mode 100644
index 0000000000..d776c2df87
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-018.xht
@@ -0,0 +1,40 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically added empty preserved whitespace</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins run in across preserved whitespace if the
+                 textnode is empty."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    #container { white-space: pre; }
+    #container > * { white-space: normal; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var t = document.getElementById("target");
+      var s = document.createTextNode("");
+      t.parentNode.insertBefore(s, t);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div id="container"><div class="run-in">Run-in header</div><div id="target">Start of block.
+    The run-in header should be inside the border around this block and there
+    should be no space between the word "header" and the word "Start".</div></div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-basic-ref.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-ref.xht
new file mode 100644
index 0000000000..597c7237a7
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-basic-ref.xht
@@ -0,0 +1,17 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+  <head>
+    <title>CSS Reftest Reference</title>
+    <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+    <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+    <style type="text/css">
+      .run-in { font-weight: bold }
+      #target { border: 2px solid black; }
+    </style>
+  </head>
+  <body>
+    <div id="target"><span class="run-in">Run-in header</span>Start of block.
+    The run-in header should be inside the border around this block and there
+    should be no space between the word "header" and the word "Start".</div>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-block-between-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-block-between-001.xht
new file mode 100644
index 0000000000..503924f23b
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-block-between-001.xht
@@ -0,0 +1,23 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - block should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="assert"
+        content="Run-ins run into a following block even if the block is empty."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div></div>
+   <div>Some text.</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-block-between-002.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-block-between-002.xht
new file mode 100644
index 0000000000..eeace162a0
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-block-between-002.xht
@@ -0,0 +1,39 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically inserted block should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Run-ins run into a following block even if the block is
+                 dynamically inserted and empty."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var t = document.getElementById("target");
+      t.parentNode.insertBefore(document.createElement("div"), t);
+      var s = document.createElement("div");
+      s.appendChild(document.createTextNode("Some text."))
+      t.parentNode.insertBefore(s, t);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-block-between-003.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-block-between-003.xht
new file mode 100644
index 0000000000..ca901199c6
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-block-between-003.xht
@@ -0,0 +1,39 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically removed block should allow running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Run-ins run into a following block even if there was another
+                 block between that was dynamically removed."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var r = document.getElementById("r");
+      r.parentNode.removeChild(r);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="r">Some text.</div>
+   <div id="target">Start of block.  The run-in header should be inside the
+    border around this block and there should be no space between the word
+    "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-block-ref.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-block-ref.xht
new file mode 100644
index 0000000000..48e01902d9
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-block-ref.xht
@@ -0,0 +1,17 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+  <head>
+    <title>CSS Reftest Reference</title>
+    <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+    <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+    <style type="text/css">
+      .run-in { font-weight: bold }
+      #target { border: 2px solid black; }
+    </style>
+  </head>
+  <body>
+    <div id="target"><div class="run-in">Run-in header</div>Start of block.
+    The run-in header should be inside the border around this block and there
+    should be a newline between the word "header" and the word "Start".</div>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-breaking-001-ref.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-breaking-001-ref.xht
new file mode 100644
index 0000000000..71701bf4a4
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-breaking-001-ref.xht
@@ -0,0 +1,21 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+  <head>
+    <title>CSS Reftest Reference</title>
+    <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+    <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+    <style type="text/css">
+      .run-in { font-weight: bold; border: 5px solid blue; }
+      #target { border: 2px solid black; padding: 1em; }
+    </style>
+  </head>
+  <body>
+    <div id="target"><span class="run-in">Run-in<br/>header</span>Start of
+    block.  The run-in header should be inside the border around this block and
+    there should be no space between the word "header" and the word "Start",
+    other than the 5px vertical blue border.  The border of the run-in must
+    have no vertical part on the right in the first line and no vertical part
+    on the left in the second line.  The border of the run-in must not extend
+    outside the border of the block.</div>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-breaking-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-breaking-001.xht
new file mode 100644
index 0000000000..7ec7bf8e3f
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-breaking-001.xht
@@ -0,0 +1,27 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - line-breaking after running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-breaking-001-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins that run in can line-break correctly,
+                 and that their borders are then painted correctly."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; border: 5px solid blue; font-weight: bold; }
+    #target { border: 2px solid black; padding: 1em; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in<br/>header</div>
+   <div id="target">Start of block.  The run-in header should be inside the
+   border around this block and there should be no space between the word
+   "header" and the word "Start", other than the 5px vertical blue border.  The
+   border of the run-in must have no vertical part on the right in the first
+   line and no vertical part on the left in the second line.  The border of the
+   run-in must not extend outside the border of the block.</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-breaking-002-ref.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-breaking-002-ref.xht
new file mode 100644
index 0000000000..1dc6994452
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-breaking-002-ref.xht
@@ -0,0 +1,26 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+  <head>
+    <title>CSS Reftest Reference</title>
+    <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+    <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+    <style type="text/css">
+      .run-in { font-weight: bold; border: 5px solid blue; direction: ltr; }
+      .one { border-left: none; }
+      .two { border-right: none; }
+      #target { border: 2px solid black; padding: 1em; direction: rtl }
+    </style>
+  </head>
+  <body>
+    <div id="target">
+      <span class="run-in one">Run-in</span><br/>
+      <span class="run-in two">header</span>Start of block.  The run-in header
+      should be inside the border around this block and there should be no
+      space between the word "header" and the word "Start".  The border of the
+      run-in must have no vertical part on the left in the first line and no
+      vertical part on the right in the second line.  It must have a vertical
+      part on the right in the first line and a vertical part on the left in
+      the second line.  The border of the run-in must not extend outside the
+      border of the block.</div>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-breaking-002.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-breaking-002.xht
new file mode 100644
index 0000000000..ac48e594f0
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-breaking-002.xht
@@ -0,0 +1,30 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - line-breaking after running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-breaking-002-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins that run in can line-break correctly,
+                 and that their borders are then painted correctly."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; border: 5px solid blue; font-weight: bold;
+              direction: rtl; }
+    #target { border: 2px solid black; padding: 1em; direction: rtl; }
+  ]]></style>
+ </head>
+ <body>
+   <span class="run-in">Run-in<br/>header</span>
+   <div id="target">Start of block.  The run-in header should be inside the
+      border around this block and there should be no space between the word
+      "header" and the word "Start".  The border of the run-in must have no
+      vertical part on the left in the first line and no vertical part on the
+      right in the second line.  It must have a vertical part on the right in
+      the first line and a vertical part on the left in the second line.  The
+      border of the run-in must not extend outside the border of the
+      block.</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-clear-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-clear-001.xht
new file mode 100644
index 0000000000..47afe8d863
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-clear-001.xht
@@ -0,0 +1,26 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - clear on a run-in should apply to the block it runs into</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#flow-control"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="assert"
+        content="Tests that clear on run-ins applies to their block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .bold { font-weight: bold; float: left }
+    #target { border: 2px solid black; }
+    .run-in { display: run-in; clear: both; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="bold">Run-in header</div>
+   <div class="run-in">Some </div>
+   <div>text.</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the
+    border around this block; it should be on a line by itself before the line
+    containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-clear-002.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-clear-002.xht
new file mode 100644
index 0000000000..f392b4f47d
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-clear-002.xht
@@ -0,0 +1,41 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - clear on a run-in should apply to the block it runs into</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#flow-control"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that dynamically set clear on run-ins applies to their block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .bold { font-weight: bold; float: left }
+    #target { border: 2px solid black; }
+    .run-in { display: run-in; }
+    .clear { clear: both; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var r = document.getElementById("r");
+      r.className = "run-in clear";
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="bold">Run-in header</div>
+   <div id="r" class="run-in">Some </div>
+   <div>text.</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the
+    border around this block; it should be on a line by itself before the line
+    containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-abspos-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-abspos-001.xht
new file mode 100644
index 0000000000..83b3be2a60
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-abspos-001.xht
@@ -0,0 +1,26 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - an abs pos child should not prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins actually run in if they have abs pos kids."/>
+  <style type="text/css"><![CDATA[
+    #container { position: relative; top: -1em; }
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; position: relative; top: 1em; }
+    .run-in > span { position: absolute; top: 0 }
+    .run-in > span + span { position: static; visibility: hidden; }
+  ]]></style>
+ </head>
+ <body>
+   <div id="container">
+     <div class="run-in">Run-in <span>header</span><span>header</span></div>
+     <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+   </div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-block-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-block-001.xht
new file mode 100644
index 0000000000..ec4f293e9c
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-block-001.xht
@@ -0,0 +1,24 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - a child block should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins don't run in if they have child blocks."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header<div></div></div>
+   <div>Some text.</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the
+    border around this block; it should be on a line by itself before the line
+    containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-block-002.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-block-002.xht
new file mode 100644
index 0000000000..d0fcecd408
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-block-002.xht
@@ -0,0 +1,36 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically inserted block child should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins don't run in if they have dynamically
+                 inserted child blocks."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      document.getElementById("r").appendChild(document.createElement("div"));
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div id="r" class="run-in">Run-in header</div>
+   <div>Some text.</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-block-003.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-block-003.xht
new file mode 100644
index 0000000000..83d04ce737
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-block-003.xht
@@ -0,0 +1,38 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically removed block child should allow running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins run in if a block child is dynamically
+                 removed."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var r = document.getElementById("r");
+      r.parentNode.removeChild(r);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header<div id="r"></div></div>
+   <div id="target">Start of block. The run-in header should be inside the
+   border around this block and there should be no space between the word
+   "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-block-004.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-block-004.xht
new file mode 100644
index 0000000000..da9a9e4273
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-block-004.xht
@@ -0,0 +1,37 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - child dynamically toggled to block display should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins don't run in if they have a child
+                 dynamically toggled to block display."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    .block { display: block; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      document.getElementById("r").className = "block";
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header<span id="r"></span></div>
+   <div>Some text.</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-block-005.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-block-005.xht
new file mode 100644
index 0000000000..c55842087a
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-block-005.xht
@@ -0,0 +1,38 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - child dynamically toggled to inline display should allow running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins run in if they have a child
+                 dynamically toggled to inline display."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    .inline { display: inline; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      document.getElementById("r").className = "inline";
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header<div id="r"></div></div>
+   <div id="target">Start of block. The run-in header should be inside the
+   border around this block and there should be no space between the word
+   "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-block-inside-inline-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-block-inside-inline-001.xht
new file mode 100644
index 0000000000..656558368b
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-block-inside-inline-001.xht
@@ -0,0 +1,25 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - a child inline containing a block should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins don't run in if they have child inlines
+                 which contain blocks."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header<span><div></div></span></div>
+   <div>Some text.</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the
+    border around this block; it should be on a line by itself before the line
+    containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-block-inside-inline-002.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-block-inside-inline-002.xht
new file mode 100644
index 0000000000..4c47b020f4
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-block-inside-inline-002.xht
@@ -0,0 +1,38 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically inserted inline child containing block should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins don't run in if they have dynamically
+                 inserted child inlines containing blocks."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var s = document.createElement("span");
+      s.appendChild(document.createElement("div"));
+      document.getElementById("r").appendChild(s);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div id="r" class="run-in">Run-in header</div>
+   <div>Some text.</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-block-inside-inline-003.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-block-inside-inline-003.xht
new file mode 100644
index 0000000000..a3b56dcb47
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-block-inside-inline-003.xht
@@ -0,0 +1,38 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically removed inline child containing a block should allow running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins run in if an inline child containing a
+                 block is dynamically removed."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var r = document.getElementById("r");
+      r.parentNode.removeChild(r);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header<span id="r"><div></div></span></div>
+   <div id="target">Start of block. The run-in header should be inside the
+   border around this block and there should be no space between the word
+   "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-float-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-float-001.xht
new file mode 100644
index 0000000000..4b1cf5df5d
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-float-001.xht
@@ -0,0 +1,25 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - a floating child should not prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins actually run in if they have floating kids."/>
+  <style type="text/css"><![CDATA[
+    #container { margin-left: -5em; }
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; clear: both; margin-left: 5em; }
+    .run-in > span { float: left; }
+  ]]></style>
+ </head>
+ <body>
+   <div id="container">
+     <div class="run-in"><span>Run-</span>in header</div>
+     <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+   </div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-inline-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-inline-001.xht
new file mode 100644
index 0000000000..15621f1071
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-inline-001.xht
@@ -0,0 +1,21 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - a child inline should not prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins actually run in if they have child inlines."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in <span>header</span></div>
+   <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-inline-002.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-inline-002.xht
new file mode 100644
index 0000000000..e37201ff33
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-inline-002.xht
@@ -0,0 +1,23 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - a child inline with table-cell child should not prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins actually run in if they have child inlines
+                 which contain table cells."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    span > span { display: table-cell; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in <span><span>header</span></span></div>
+   <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-inline-003.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-inline-003.xht
new file mode 100644
index 0000000000..413c386054
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-inline-003.xht
@@ -0,0 +1,26 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - a child inline with table-cell child with an abs pos child should not prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins actually run in if they have child inlines
+                 which contain table cells which contain abs pos kids."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; position: relative; }
+    .run-in > span { visibility: hidden; } /* tests that the abs pos actually
+                                              shows up */
+    .run-in > span > span { display: table-cell; visibility: visible; }
+    .run-in > span > span > span { position: absolute; top: 0; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in <span><span><span>header</span></span></span><span>header</span></div>
+   <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-inline-004.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-inline-004.xht
new file mode 100644
index 0000000000..6c40107594
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-inline-004.xht
@@ -0,0 +1,26 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - a child inline with table-cell child with a floating child should not prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins actually run in if they have child inlines
+                 which contain table cells which contain floating kids."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; clear: both; }
+    .run-in > span { visibility: hidden; } /* tests that the float actually
+                                              shows up */
+    .run-in > span > span { display: table-cell; visibility: visible; }
+    .run-in > span > span > span { float: left; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in"><span><span><span>Run-</span></span></span>in header</div>
+   <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-inline-005.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-inline-005.xht
new file mode 100644
index 0000000000..6be696b4a1
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-inline-005.xht
@@ -0,0 +1,23 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - a child inline with table-row child should not prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins actually run in if they have child inlines
+                 which contain table rowss."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    span > span { display: table-row; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in <span><span>header</span></span></div>
+   <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-inline-006.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-inline-006.xht
new file mode 100644
index 0000000000..7cd2ad774f
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-inline-006.xht
@@ -0,0 +1,25 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - a child inline with an abs pos child should not prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins actually run in if they have child inlines
+                 which contain abs pos kids."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; position: relative; }
+    .run-in > span { visibility: hidden; } /* tests that the abs pos actually
+                                              shows up */
+    .run-in > span > span { position: absolute; visibility: visible; top: 0}
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in <span><span>header</span></span><span>header</span></div>
+   <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-inline-007.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-inline-007.xht
new file mode 100644
index 0000000000..9ff76e714e
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-inline-007.xht
@@ -0,0 +1,25 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - a child inline with a floating child should not prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins actually run in if they have child inlines
+                 which contain floating kids."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; clear: both; }
+    .run-in > span { visibility: hidden; } /* tests that the float actually
+                                              shows up */
+    .run-in > span > span { float: left; visibility: visible; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in"><span><span>Run-</span></span>in header</div>
+   <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-inline-block-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-inline-block-001.xht
new file mode 100644
index 0000000000..663b948308
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-inline-block-001.xht
@@ -0,0 +1,22 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - a child inline-block should not prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins actually run in if they have child inline-blocks."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    .run-in > span { display: inline-block }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in <span>header</span></div>
+   <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-inline-table-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-inline-table-001.xht
new file mode 100644
index 0000000000..b916dbc711
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-inline-table-001.xht
@@ -0,0 +1,23 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - a child inline-table should not prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins actually run in if they have child
+                 inline-tables."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    .run-in > span { display: inline-table }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in <span>header</span></div>
+   <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-relpos-block-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-relpos-block-001.xht
new file mode 100644
index 0000000000..a22138e0c0
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-relpos-block-001.xht
@@ -0,0 +1,26 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - a child rel pos block should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins don't run in if they have child rel pos
+                 blocks."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    .run-in div { position: relative; top: 2em; left: 3em; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header<div></div></div>
+   <div>Some text.</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the
+    border around this block; it should be on a line by itself before the line
+    containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-relpos-block-002.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-relpos-block-002.xht
new file mode 100644
index 0000000000..64fa6f6e1a
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-relpos-block-002.xht
@@ -0,0 +1,37 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically inserted rel pos block child should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins don't run in if they have dynamically
+                 inserted child rel pos blocks."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    .run-in div { position: relative; top: 2em; left: 3em; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      document.getElementById("r").appendChild(document.createElement("div"));
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div id="r" class="run-in">Run-in header</div>
+   <div>Some text.</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-relpos-block-003.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-relpos-block-003.xht
new file mode 100644
index 0000000000..c5756fce48
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-relpos-block-003.xht
@@ -0,0 +1,39 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically removed rel pos block child should allow running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins run in if a rel pos block child is dynamically
+                 removed."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    .run-in div { position: relative; top: 2em; left: 3em; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var r = document.getElementById("r");
+      r.parentNode.removeChild(r);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header<div id="r"></div></div>
+   <div id="target">Start of block. The run-in header should be inside the
+   border around this block and there should be no space between the word
+   "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-run-in-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-run-in-001.xht
new file mode 100644
index 0000000000..cebbfef67c
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-run-in-001.xht
@@ -0,0 +1,25 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - a child run-in should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins don't run in if they have child run-ins."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    .run-in div { display: run-in; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header<div></div></div>
+   <div>Some text.</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the
+    border around this block; it should be on a line by itself before the line
+    containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-run-in-002.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-run-in-002.xht
new file mode 100644
index 0000000000..e3f978be08
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-run-in-002.xht
@@ -0,0 +1,37 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically inserted run-in child should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins don't run in if they have dynamically
+                 inserted child run-ins."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    .run-in div { display: run-in; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      document.getElementById("r").appendChild(document.createElement("div"));
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div id="r" class="run-in">Run-in header</div>
+   <div>Some text.</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-run-in-003.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-run-in-003.xht
new file mode 100644
index 0000000000..5a812b382b
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-run-in-003.xht
@@ -0,0 +1,39 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically removed run-in child should allow running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins run in if a run-in child is dynamically
+                 removed."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    .run-in div { display: run-in; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var r = document.getElementById("r");
+      r.parentNode.removeChild(r);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header<div id="r"></div></div>
+   <div id="target">Start of block. The run-in header should be inside the
+   border around this block and there should be no space between the word
+   "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-001.xht
new file mode 100644
index 0000000000..9001a7e4e0
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-001.xht
@@ -0,0 +1,25 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - a child table should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins don't run in if they have child tables."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    .run-in div { display: table; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header<div></div></div>
+   <div>Some text.</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the
+    border around this block; it should be on a line by itself before the line
+    containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-002.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-002.xht
new file mode 100644
index 0000000000..3fd6adda3a
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-002.xht
@@ -0,0 +1,37 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically inserted table child should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins don't run in if they have dynamically
+                 inserted child tables."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    .run-in div { display: table; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      document.getElementById("r").appendChild(document.createElement("div"));
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div id="r" class="run-in">Run-in header</div>
+   <div>Some text.</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-003.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-003.xht
new file mode 100644
index 0000000000..ab76e87e2d
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-003.xht
@@ -0,0 +1,39 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically removed table child should allow running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins run in if a table child is dynamically
+                 removed."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    .run-in div { display: table; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var r = document.getElementById("r");
+      r.parentNode.removeChild(r);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header<div id="r"></div></div>
+   <div id="target">Start of block. The run-in header should be inside the
+   border around this block and there should be no space between the word
+   "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-caption-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-caption-001.xht
new file mode 100644
index 0000000000..d98b535a3d
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-caption-001.xht
@@ -0,0 +1,22 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - a child table-caption should not prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins actually run in if they have child table-captions."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    .run-in > span { display: table-caption }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in <span>header</span></div>
+   <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-cell-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-cell-001.xht
new file mode 100644
index 0000000000..433e1c65de
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-cell-001.xht
@@ -0,0 +1,22 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - a child table-cell should not prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins actually run in if they have child table-cells."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    .run-in > span { display: table-cell }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in <span>header</span></div>
+   <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-column-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-column-001.xht
new file mode 100644
index 0000000000..d9fc2f0318
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-column-001.xht
@@ -0,0 +1,22 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - a child table-column should not prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins actually run in if they have child table-columns."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    .run-in > span { display: table-column }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header<span></span></div>
+   <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-column-group-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-column-group-001.xht
new file mode 100644
index 0000000000..f4aeb8b7b0
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-column-group-001.xht
@@ -0,0 +1,22 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - a child table-column should not prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins actually run in if they have child table-columns."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    .run-in > span { display: table-column-group }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header<span></span></div>
+   <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-inside-inline-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-inside-inline-001.xht
new file mode 100644
index 0000000000..6270d647f9
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-inside-inline-001.xht
@@ -0,0 +1,26 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - a child inline containing a table should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins don't run in if they have child inlines
+                 which contain tables."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    .run-in div { display: table; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header<span><div></div></span></div>
+   <div>Some text.</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the
+    border around this block; it should be on a line by itself before the line
+    containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-inside-inline-002.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-inside-inline-002.xht
new file mode 100644
index 0000000000..edd543d45b
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-inside-inline-002.xht
@@ -0,0 +1,39 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically inserted inline child containing table should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins don't run in if they have dynamically
+                 inserted child inlines containing tables."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    .run-in div { display: table; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var s = document.createElement("span");
+      s.appendChild(document.createElement("div"));
+      document.getElementById("r").appendChild(s);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div id="r" class="run-in">Run-in header</div>
+   <div>Some text.</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-inside-inline-003.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-inside-inline-003.xht
new file mode 100644
index 0000000000..5df9c526c3
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-inside-inline-003.xht
@@ -0,0 +1,39 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically removed inline child containing a table should allow running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins run in if an inline child containing a
+                 table is dynamically removed."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    .run-in div { display: table; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var r = document.getElementById("r");
+      r.parentNode.removeChild(r);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header<span id="r"><div></div></span></div>
+   <div id="target">Start of block. The run-in header should be inside the
+   border around this block and there should be no space between the word
+   "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-row-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-row-001.xht
new file mode 100644
index 0000000000..eb1c69292c
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-row-001.xht
@@ -0,0 +1,22 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - a child table-row should not prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins actually run in if they have child table-rows."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    .run-in > span { display: table-row }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in <span>header</span></div>
+   <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-row-group-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-row-group-001.xht
new file mode 100644
index 0000000000..9d8936f05f
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-contains-table-row-group-001.xht
@@ -0,0 +1,22 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - a child table-row-group should not prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins actually run in if they have child table-row-groupss."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    .run-in > span { display: table-row-group }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in <span>header</span></div>
+   <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-display-none-between-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-display-none-between-001.xht
new file mode 100644
index 0000000000..bdcd34d277
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-display-none-between-001.xht
@@ -0,0 +1,24 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - display:none should not prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins actually run in if there is a display:none
+                 element between the run-in and the following block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    .none { display: none; }
+    #target { border: 2px solid black; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div class="none"></div>
+   <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-display-none-between-002.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-display-none-between-002.xht
new file mode 100644
index 0000000000..c9dddee3cd
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-display-none-between-002.xht
@@ -0,0 +1,41 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - block set to display:none should allow running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins run in if a block is dynamically set to
+                 display:none between them and the following block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    .none { display: none; }
+    #target { border: 2px solid black; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      document.normalize();
+      var r = document.getElementById("r");
+      r.className = "none";
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="r">Some text.</div>
+   <div id="target">Start of block.  The run-in header should be inside the
+    border around this block and there should be no space between the word
+    "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-display-none-between-003.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-display-none-between-003.xht
new file mode 100644
index 0000000000..ac28260492
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-display-none-between-003.xht
@@ -0,0 +1,38 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - inline toggled from display:none should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins don't run in if an inline between them and
+                 the block is toggled from display:none."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    .none { display: none; }
+    #target { border: 2px solid black; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var r = document.getElementById("r");
+      r.className = "";
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <span id="r" class="none">Some text.</span>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-fixedpos-between-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-fixedpos-between-001.xht
new file mode 100644
index 0000000000..11396660f2
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-fixedpos-between-001.xht
@@ -0,0 +1,24 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - fixed pos should not prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins actually run in if there is an fixed
+                 positioned element between the run-in and the following block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    .fixedpos { position: fixed; visibility: hidden; }
+    #target { border: 2px solid black; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div class="fixedpos"></div>
+   <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-fixedpos-between-002.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-fixedpos-between-002.xht
new file mode 100644
index 0000000000..e97fe47cad
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-fixedpos-between-002.xht
@@ -0,0 +1,40 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - block set to fixed pos should allow running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins run in if a block is dynamically set to
+                 fixed positioned between them and the following block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    .fixedpos { position: fixed; visibility: hidden; }
+    #target { border: 2px solid black; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var r = document.getElementById("r");
+      r.className = "fixedpos";
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="r">Some text.</div>
+   <div id="target">Start of block.  The run-in header should be inside the
+    border around this block and there should be no space between the word
+    "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-fixedpos-between-003.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-fixedpos-between-003.xht
new file mode 100644
index 0000000000..9af28a390c
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-fixedpos-between-003.xht
@@ -0,0 +1,38 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - inline toggled from fixed pos should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins don't run in if an inline between them and
+                 the block is toggled from being fixed positioned."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    .fixedpos { position: fixed; visibility: hidden; }
+    #target { border: 2px solid black; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var r = document.getElementById("r");
+      r.className = "";
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <span id="r" class="fixedpos">Some text.</span>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-float-between-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-float-between-001.xht
new file mode 100644
index 0000000000..3ac540cc1c
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-float-between-001.xht
@@ -0,0 +1,24 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - floatshould not prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins actually run in if there is a float
+                 element between the run-in and the following block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    .float { float: right; visibility: hidden; }
+    #target { border: 2px solid black; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div class="float"></div>
+   <div id="target">Start of block.  The run-in header should be inside the border around this block and there should be no space between the word "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-float-between-002.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-float-between-002.xht
new file mode 100644
index 0000000000..a5ad3c7de4
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-float-between-002.xht
@@ -0,0 +1,40 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - block set to float should allow running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins run in if a block is dynamically set to
+                 float between them and the following block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    .float { float: right; visibility: hidden; }
+    #target { border: 2px solid black; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var r = document.getElementById("r");
+      r.className = "float";
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="r">Some text.</div>
+   <div id="target">Start of block.  The run-in header should be inside the
+    border around this block and there should be no space between the word
+    "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-float-between-003.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-float-between-003.xht
new file mode 100644
index 0000000000..8d4b9e52f2
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-float-between-003.xht
@@ -0,0 +1,38 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - inline toggled from float should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins don't run in if an inline between them and
+                 the block is toggled from float."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    .float { float: right; visibility: hidden; }
+    #target { border: 2px solid black; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var r = document.getElementById("r");
+      r.className = "";
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <span id="r" class="float">Some text.</span>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-inherit-001-ref.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-inherit-001-ref.xht
new file mode 100644
index 0000000000..64f0a45e7d
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-inherit-001-ref.xht
@@ -0,0 +1,20 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+  <head>
+    <title>CSS Reftest Reference</title>
+    <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+    <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+    <style type="text/css">
+      .run-in { font-weight: bold; color: green; border: 10px outset orange; }
+      #target { border: 2px solid black; margin: 2em; padding: 10px; }
+      body { border: 10px outset orange; }
+    </style>
+  </head>
+  <body>
+    <div id="target"><span class="run-in">Run-in header</span>Start of block.
+    The run-in header should be inside the border around this block, should be
+    colored green, and should have an outset orange border.  There should be
+    2em of space on each side between the black border of the block and outset
+    orange border around it.</div>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-inherit-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-inherit-001.xht
new file mode 100644
index 0000000000..f87e093ea9
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-inherit-001.xht
@@ -0,0 +1,28 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - run-in property inheritance</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-inherit-001-ref.xht"/>
+  <meta name="assert"
+        content="Tests property inheritance for run-ins, and margin collapsing
+                 for the block following a run-in.  Should inherit from our content parent, and the margins should not collapse through a border."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold; border: inherit}
+    #target { border: 2px solid black; color: black; margin: 2em; padding: 10px }
+    #container { color: green; border: 10px outset orange; }
+  ]]></style>
+ </head>
+ <body>
+   <div id="container">
+     <div class="run-in">Run-in header</div>
+     <div id="target">Start of block.  The run-in header should be inside the
+       border around this block, should be colored green, and should have an
+       outset orange border.  There should be 2em of space on each side between
+       the black border of the block and outset orange border around it.</div>
+   </div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-inheritance-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-inheritance-001.xht
new file mode 100644
index 0000000000..c1072450bb
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-inheritance-001.xht
@@ -0,0 +1,31 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Run-in boxes and inheritance</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in" />
+        <meta name="assert" content="Run-in boxes inherit properties from its parent element." />
+        <style type="text/css">
+            div
+            {
+                color: orange;
+            }
+            #span1
+            {
+                display: run-in;
+            }
+            #span2
+            {
+                background: blue;
+                display: block;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the "Filler Text" below is orange and is completely contained within the blue box.</p>
+        <div>
+            <span id="span1">Filler Text</span>
+            <span id="span2">Filler Text</span>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-inline-between-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-inline-between-001.xht
new file mode 100644
index 0000000000..76710eafd9
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-inline-between-001.xht
@@ -0,0 +1,23 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - inline should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins don't run in if there's an inline between
+                 them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <span>Some text.</span>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-inline-between-002.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-inline-between-002.xht
new file mode 100644
index 0000000000..bba6f3b246
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-inline-between-002.xht
@@ -0,0 +1,38 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically inserted inline should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins don't run in if there's a dynamically
+                 inserted inline between them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var t = document.getElementById("target");
+      var s = document.createElement("span");
+      s.appendChild(document.createTextNode("Some text."))
+      t.parentNode.insertBefore(s, t);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-inline-between-003.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-inline-between-003.xht
new file mode 100644
index 0000000000..358b4231c9
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-inline-between-003.xht
@@ -0,0 +1,39 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically removed inline should allow running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins run in if an inline is dynamically removed
+                 from between them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var r = document.getElementById("r");
+      r.parentNode.removeChild(r);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <span id="r">Some text.</span>
+   <div id="target">Start of block.  The run-in header should be inside the
+    border around this block and there should be no space between the word
+    "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-inline-block-between-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-inline-block-between-001.xht
new file mode 100644
index 0000000000..17271636b2
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-inline-block-between-001.xht
@@ -0,0 +1,24 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - inline-block should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins don't run in if there's an inline-block
+                 between them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    span { display: inline-block; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <span>Some text.</span>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-inline-block-between-002.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-inline-block-between-002.xht
new file mode 100644
index 0000000000..1ceb4bed25
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-inline-block-between-002.xht
@@ -0,0 +1,39 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically inserted inline-block should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins don't run in if there's a dynamically
+                 inserted inline-block between them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    span { display: inline-block; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var t = document.getElementById("target");
+      var s = document.createElement("span");
+      s.appendChild(document.createTextNode("Some text."))
+      t.parentNode.insertBefore(s, t);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-inline-block-between-003.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-inline-block-between-003.xht
new file mode 100644
index 0000000000..351f27756e
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-inline-block-between-003.xht
@@ -0,0 +1,40 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically removed inline-block should allow running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins run in if an inline-block is dynamically
+                 removed from between them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    span { display: inline-block; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var r = document.getElementById("r");
+      r.parentNode.removeChild(r);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <span id="r">Some text.</span>
+   <div id="target">Start of block.  The run-in header should be inside the
+    border around this block and there should be no space between the word
+    "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-inline-table-between-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-inline-table-between-001.xht
new file mode 100644
index 0000000000..c7449056b0
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-inline-table-between-001.xht
@@ -0,0 +1,24 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - inline-table should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins don't run in if there's a inline-table between
+                 them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    span { display: inline-table; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <span>Some text.</span>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-inline-table-between-002.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-inline-table-between-002.xht
new file mode 100644
index 0000000000..49164c05ec
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-inline-table-between-002.xht
@@ -0,0 +1,39 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically inserted inline-table should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins don't run in if there's a dynamically
+                 inserted inline-table between them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    span { display: inline-table; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var t = document.getElementById("target");
+      var s = document.createElement("span");
+      s.appendChild(document.createTextNode("Some text."))
+      t.parentNode.insertBefore(s, t);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-inline-table-between-003.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-inline-table-between-003.xht
new file mode 100644
index 0000000000..9b73d0cadc
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-inline-table-between-003.xht
@@ -0,0 +1,40 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically removed inline-table should allow running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins run in if a inline-table is dynamically removed
+                 from between them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    span { display: inline-table; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var r = document.getElementById("r");
+      r.parentNode.removeChild(r);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <span id="r">Some text.</span>
+   <div id="target">Start of block.  The run-in header should be inside the
+    border around this block and there should be no space between the word
+    "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-linebox-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-linebox-001.xht
new file mode 100644
index 0000000000..128cd3e386
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-linebox-001.xht
@@ -0,0 +1,24 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: run-in and sibling blocks</title>
+  <link rel="author" title="Ian Hickson" href="mailto:ian@hixie.ch"/>
+  <link rel="author" title="Elika J. Etemad" href="http://fantasai.inkedblade.net/contact" />
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="alternate" href="http://www.hixie.ch/tests/adhoc/css/box/run-in/001.xml" type="application/xhtml+xml" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in" />
+  <style type="text/css">
+   .r { display: run-in; color: blue; }
+   .b { background: blue; display: block; }
+   .fail { background: red; line-height: 0; margin-top: 1em; color: white; }
+  </style>
+ </head>
+ <body>
+  <p>There should be a blue box below.</p>
+  <div class="r">FAIL</div>
+  <div class="b"></div>
+  <div class="fail">
+   FAIL
+  </div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-linebox-002.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-linebox-002.xht
new file mode 100644
index 0000000000..db741a1e8a
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-linebox-002.xht
@@ -0,0 +1,23 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: run-in and the line box model</title>
+  <link rel="author" title="Ian Hickson" href="mailto:ian@hixie.ch"/>
+  <link rel="author" title="Elika J. Etemad" href="http://fantasai.inkedblade.net/contact" />
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="alternate" href="http://www.hixie.ch/tests/adhoc/css/box/run-in/002.xml" type="application/xhtml+xml"/>
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in" />
+  <meta name="assert" content="A run-in element inherits (line-height) from its document tree parent"/>
+  <style type="text/css">
+    div { font-family: monospace; }
+   .r { color: blue; display: run-in; }
+   .b { background: blue; line-height: 0; }
+   span { color: blue; }
+  </style>
+ </head>
+ <body>
+  <p>There should be a blue box below.</p>
+  <div class="r">FAIL</div>
+  <div class="b"><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;FAIL</span></div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-listitem-between-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-listitem-between-001.xht
new file mode 100644
index 0000000000..bfe6d35ca7
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-listitem-between-001.xht
@@ -0,0 +1,25 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - block should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins don't run in if there's a list-item between
+                 them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    .listitem { display: list-item; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div class="listitem"></div>
+   <div class="listitem">Some text.</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-listitem-between-002.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-listitem-between-002.xht
new file mode 100644
index 0000000000..1eda2aa7b2
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-listitem-between-002.xht
@@ -0,0 +1,41 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically inserted block should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins don't run in if there's a dynamically
+                 inserted list-item between them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    #r { display: list-item; list-style-type: ""; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var t = document.getElementById("target");
+      t.parentNode.insertBefore(document.createElement("div"), t);
+      var s = document.createElement("div");
+      s.appendChild(document.createTextNode("Some text."))
+      s.id = "r";
+      t.parentNode.insertBefore(s, t);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-listitem-between-003.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-listitem-between-003.xht
new file mode 100644
index 0000000000..06fda02c74
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-listitem-between-003.xht
@@ -0,0 +1,40 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically removed block should allow running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins run in if a list-item is dynamically removed
+                 from between them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    #r { display: list-item; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var r = document.getElementById("r");
+      r.parentNode.removeChild(r);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="r">Some text.</div>
+   <div id="target">Start of block.  The run-in header should be inside the
+    border around this block and there should be no space between the word
+    "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-pre-ref.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-pre-ref.xht
new file mode 100644
index 0000000000..541d182a5e
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-pre-ref.xht
@@ -0,0 +1,17 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+  <head>
+    <title>CSS Reftest Reference</title>
+    <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+    <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+    <style type="text/css">
+      .run-in { font-weight: bold }
+      #target { border: 2px solid black; }
+      #container { white-space: pre; }
+      #container > * { white-space: normal; }
+    </style>
+  </head>
+  <body>
+    <div id="container"><div class="run-in">Run-in header</div> <div id="target">Start of block. The run-in header should be outside the border around this block and there should be a blank line between the run-in header and this block.</div></div>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-relpos-between-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-relpos-between-001.xht
new file mode 100644
index 0000000000..c16b9fc942
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-relpos-between-001.xht
@@ -0,0 +1,25 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - rel pos inline should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins don't run in if there's a rel pos inline
+                 between them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    .outer { position: relative; top: 50px; }
+    .inner { position: relative; top: -50px; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <span class="outer"><span class="inner">Some text.</span></span>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-relpos-between-002.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-relpos-between-002.xht
new file mode 100644
index 0000000000..bb7c91a0c6
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-relpos-between-002.xht
@@ -0,0 +1,44 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically inserted rel pos inline should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins don't run in if there's a dynamically
+                 inserted rel pos inline between them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    .outer { position: relative; top: 50px; }
+    .inner { position: relative; top: -50px; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var t = document.getElementById("target");
+      var s = document.createElement("span");
+      s.className = "inner";
+      s.appendChild(document.createTextNode("Some text."));
+      var s2 = document.createElement("span");
+      s2.className = "outer";
+      s2.appendChild(s);
+      t.parentNode.insertBefore(s2, t);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-relpos-between-003.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-relpos-between-003.xht
new file mode 100644
index 0000000000..cea7d4f4b0
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-relpos-between-003.xht
@@ -0,0 +1,41 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically removed rel pos inline should allow running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins run in if a rel pos inline is dynamically
+                 removed from between them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    .outer { position: relative; top: 50px; }
+    .inner { position: relative; top: -50px; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var r = document.getElementById("r");
+      r.parentNode.removeChild(r);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <span id="r" class="outer"><span class="inner">Some text.</span></span>
+   <div id="target">Start of block.  The run-in header should be inside the
+    border around this block and there should be no space between the word
+    "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-replaced-001-ref.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-replaced-001-ref.xht
new file mode 100644
index 0000000000..e6c53abfac
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-replaced-001-ref.xht
@@ -0,0 +1,15 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+  <head>
+    <title>CSS Reftest Reference</title>
+    <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+    <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+    <style type="text/css">
+      #target { border: 2px solid black; width: 500px; height: 200px; }
+      #target > img { width: 100px; height: 100px; }
+    </style>
+  </head>
+  <body>
+    <div id="target"><img src="support/swatch-blue.png"/>The blue square should be inside the border of this block, a square, and half the block's height.</div>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-replaced-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-replaced-001.xht
new file mode 100644
index 0000000000..01af2d38a3
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-replaced-001.xht
@@ -0,0 +1,26 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - basic replaced element</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-replaced-001-ref.xht"/>
+  <meta name="assert"
+        content="Tests that replaced elements can actually run in and that
+                 they ten get sized correctly."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; width: 20%; height: 50% }
+    #target { border: 2px solid black;  width: 500px; height: 200px; }
+    #container { height: 0; width: 0; }
+  ]]></style>
+ </head>
+ <body>
+   <div id="container">
+     <img class="run-in" src="support/swatch-blue.png" />
+     <div id="target">Start of block.  The blue square should be inside the
+       border of this block, a square, and half the block's height.</div>
+   </div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-restyle-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-restyle-001.xht
new file mode 100644
index 0000000000..05bd61a0b5
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-restyle-001.xht
@@ -0,0 +1,36 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - should run out when they stop being run-ins</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins don't run once they stop being run-ins."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; }
+    .bold { font-weight: bold; }
+    #target { border: 2px solid black; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      document.getElementById("r").className = "bold";
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div id="r" class="run-in bold">Run-in header</div>
+   <div>Some text.</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-restyle-002.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-restyle-002.xht
new file mode 100644
index 0000000000..40d23e4fb0
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-restyle-002.xht
@@ -0,0 +1,36 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - should run out when following block becomes an inline</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins don't run once their following block becomes an inline."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold; }
+    #target { border: 2px solid black; }
+    .inline { display: inline; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      document.getElementById("r").className = "inline";
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="r">Some text.</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-restyle-003.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-restyle-003.xht
new file mode 100644
index 0000000000..226081278d
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-restyle-003.xht
@@ -0,0 +1,37 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - should run in when following inline becomes a block</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins run in when the inline after them becomes a block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold; }
+    #target { border: 2px solid black; }
+    .block { display: block; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      document.getElementById("target").className = "block";
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <span id="target">Start of block.
+    The run-in header should be inside the border around this block and there
+    should be no space between the word "header" and the word "Start".</span>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-run-in-between-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-run-in-between-001.xht
new file mode 100644
index 0000000000..13077566c0
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-run-in-between-001.xht
@@ -0,0 +1,24 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - run in that has not run in should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins don't run in if there's a run in that has
+                 not run in between them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    #r { display: run-in; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="r">Some text.<div><!--Make us not run in--></div></div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-run-in-between-002.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-run-in-between-002.xht
new file mode 100644
index 0000000000..220c45ed24
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-run-in-between-002.xht
@@ -0,0 +1,42 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically inserted run-in which does not run in should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins don't run in if there's a dynamically
+                 inserted run-in which has not run in between them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    #r { display: run-in; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var t = document.getElementById("target");
+      t.parentNode.insertBefore(document.createElement("div"), t);
+      var s = document.createElement("div");
+      s.appendChild(document.createTextNode("Some text."))
+      s.id = "r";
+      s.appendChild(document.createElement("div")); /* make s not run in */
+      t.parentNode.insertBefore(s, t);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-run-in-between-003.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-run-in-between-003.xht
new file mode 100644
index 0000000000..555774420c
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-run-in-between-003.xht
@@ -0,0 +1,40 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically removed run-in which did not run in should allow running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins run in if a run-in which has not run in is
+                 dynamically removed from between them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    #r { display: run-in }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var r = document.getElementById("r");
+      r.parentNode.removeChild(r);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="r">Some text.<div><!--Make us not run in--></div></div>
+   <div id="target">Start of block.  The run-in header should be inside the
+    border around this block and there should be no space between the word
+    "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-run-in-between-004.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-run-in-between-004.xht
new file mode 100644
index 0000000000..c9af78ddb7
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-run-in-between-004.xht
@@ -0,0 +1,25 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - run in that has run in should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins don't run in if there's a run-in that has
+                 run in between them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    #r { display: run-in; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="r">Some </div>
+   <div>text.</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-run-in-between-005.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-run-in-between-005.xht
new file mode 100644
index 0000000000..9839d9bd59
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-run-in-between-005.xht
@@ -0,0 +1,44 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically inserted run-in which runs in should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins don't run in if there's a dynamically
+                 inserted run-in which has run in between them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    #r { display: run-in; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var t = document.getElementById("target");
+      var s = document.createElement("div");
+      s.appendChild(document.createTextNode("text."))
+      t.parentNode.insertBefore(s, t);
+      flushLayout(document.documentElement);
+      var s2 = document.createElement("div");
+      s2.appendChild(document.createTextNode("Some "))
+      s2.id = "r";
+      s.parentNode.insertBefore(s2, s);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-run-in-between-006.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-run-in-between-006.xht
new file mode 100644
index 0000000000..ae2bceef2d
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-run-in-between-006.xht
@@ -0,0 +1,40 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically removed run-in which ran in should allow running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins run in if a run-in which has run in is
+                 dynamically removed from between them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    #r { display: run-in }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var r = document.getElementById("r");
+      r.parentNode.removeChild(r);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="r">Some text.</div>
+   <div id="target">Start of block.  The run-in header should be inside the
+    border around this block and there should be no space between the word
+    "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-run-in-between-007.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-run-in-between-007.xht
new file mode 100644
index 0000000000..910831a742
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-run-in-between-007.xht
@@ -0,0 +1,41 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - run-in which runs in should prevent running in of dynamically inserted run-in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that dynamically inserted run-ins don't run in if
+                 there's a run-in which has run in between them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    #r { display: run-in; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var r = document.getElementById("r");
+      var s = document.createElement("div");
+      s.appendChild(document.createTextNode("Run-in header"));
+      s.className = "run-in";
+      r.parentNode.insertBefore(s, r);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div id="r">Some </div>
+   <div>text.</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-run-in-between-008.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-run-in-between-008.xht
new file mode 100644
index 0000000000..00e24408e8
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-run-in-between-008.xht
@@ -0,0 +1,41 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - run-in which does not run in should prevent running in of dynamically inserted run-in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that dynamically inserted run-ins don't run in if
+                 there's a run-in which has not run in between them and the
+                 block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    #r { display: run-in; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var r = document.getElementById("r");
+      var s = document.createElement("div");
+      s.appendChild(document.createTextNode("Run-in header"));
+      s.className = "run-in";
+      r.parentNode.insertBefore(s, r);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div id="r">Some text.<div></div></div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-table-between-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-table-between-001.xht
new file mode 100644
index 0000000000..79a98d1fb3
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-table-between-001.xht
@@ -0,0 +1,24 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - table should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins don't run in if there's a table between
+                 them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    span { display: table; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <span>Some text.</span>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-table-between-002.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-table-between-002.xht
new file mode 100644
index 0000000000..2ca8027546
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-table-between-002.xht
@@ -0,0 +1,39 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically inserted table should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins don't run in if there's a dynamically
+                 inserted table between them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    span { display: table; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var t = document.getElementById("target");
+      var s = document.createElement("span");
+      s.appendChild(document.createTextNode("Some text."))
+      t.parentNode.insertBefore(s, t);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-table-between-003.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-table-between-003.xht
new file mode 100644
index 0000000000..aa4d9f4497
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-table-between-003.xht
@@ -0,0 +1,40 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically removed table should allow running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins run in if a table is dynamically removed
+                 from between them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    span { display: table; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var r = document.getElementById("r");
+      r.parentNode.removeChild(r);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <span id="r">Some text.</span>
+   <div id="target">Start of block.  The run-in header should be inside the
+    border around this block and there should be no space between the word
+    "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-table-cell-between-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-table-cell-between-001.xht
new file mode 100644
index 0000000000..18fcc2f797
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-table-cell-between-001.xht
@@ -0,0 +1,24 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - table-cell should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins don't run in if there's a table-cell between
+                 them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    span { display: table-cell; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <span>Some text.</span>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-table-cell-between-002.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-table-cell-between-002.xht
new file mode 100644
index 0000000000..04f5e80c53
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-table-cell-between-002.xht
@@ -0,0 +1,39 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically inserted table-cell should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins don't run in if there's a dynamically
+                 inserted table-cell between them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    span { display: table-cell; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var t = document.getElementById("target");
+      var s = document.createElement("span");
+      s.appendChild(document.createTextNode("Some text."))
+      t.parentNode.insertBefore(s, t);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-table-cell-between-003.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-table-cell-between-003.xht
new file mode 100644
index 0000000000..49ab645554
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-table-cell-between-003.xht
@@ -0,0 +1,40 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically removed table-cell should allow running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins run in if a table-cell is dynamically removed
+                 from between them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    span { display: table-cell; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var r = document.getElementById("r");
+      r.parentNode.removeChild(r);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <span id="r">Some text.</span>
+   <div id="target">Start of block.  The run-in header should be inside the
+    border around this block and there should be no space between the word
+    "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-table-row-between-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-table-row-between-001.xht
new file mode 100644
index 0000000000..06b0852bb8
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-table-row-between-001.xht
@@ -0,0 +1,24 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - table-row should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins don't run in if there's a table-row between
+                 them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    span { display: table-row; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <span>Some text.</span>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-table-row-between-002.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-table-row-between-002.xht
new file mode 100644
index 0000000000..a5e069daac
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-table-row-between-002.xht
@@ -0,0 +1,39 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically inserted table-row should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins don't run in if there's a dynamically
+                 inserted table-row between them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    span { display: table-row; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var t = document.getElementById("target");
+      var s = document.createElement("span");
+      s.appendChild(document.createTextNode("Some text."))
+      t.parentNode.insertBefore(s, t);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-table-row-between-003.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-table-row-between-003.xht
new file mode 100644
index 0000000000..755b46351b
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-table-row-between-003.xht
@@ -0,0 +1,40 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically removed table-row should allow running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins run in if a table-row is dynamically removed
+                 from between them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+    span { display: table-row; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var r = document.getElementById("r");
+      r.parentNode.removeChild(r);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <span id="r">Some text.</span>
+   <div id="target">Start of block.  The run-in header should be inside the
+    border around this block and there should be no space between the word
+    "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-text-between-001.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-text-between-001.xht
new file mode 100644
index 0000000000..cdbd7acca0
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-text-between-001.xht
@@ -0,0 +1,23 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - text should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="assert"
+        content="Tests that run-ins don't run in if there's text between them
+                 and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+  ]]></style>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   Some text.
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-text-between-002.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-text-between-002.xht
new file mode 100644
index 0000000000..545dee956e
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-text-between-002.xht
@@ -0,0 +1,36 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically inserted text should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins don't run in if there's dynamically
+                 inserted text between them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var t = document.getElementById("target");
+      t.parentNode.insertBefore(document.createTextNode("Some text."), t);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-text-between-003.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-text-between-003.xht
new file mode 100644
index 0000000000..66a4451d32
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-text-between-003.xht
@@ -0,0 +1,36 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically changed text should prevent running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-text-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins don't run in if there's dynamically
+                 changed text between them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var t = document.getElementById("target");
+      t.previousSibling.data = "Some text.";
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   <div id="target">Start of block.  The run-in header should NOT be inside the border around this block; it should be on a line by itself before the line containing "Some text".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-text-between-004.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-text-between-004.xht
new file mode 100644
index 0000000000..9411b64819
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-text-between-004.xht
@@ -0,0 +1,39 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically removed text should allow running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins run in if text is dynamically removed from
+                 between them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var t = document.getElementById("target");
+      t.parentNode.removeChild(t.previousSibling);
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   Some text.
+   <div id="target">Start of block.  The run-in header should be inside the
+    border around this block and there should be no space between the word
+    "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-text-between-005.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-text-between-005.xht
new file mode 100644
index 0000000000..e981b9e2d3
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-text-between-005.xht
@@ -0,0 +1,39 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head>
+  <title>CSS Test: Run in - dynamically set to whitespace text should allow running in</title>
+  <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+  <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+  <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#run-in"/>
+  <link rel="match" href="run-in-basic-ref.xht"/>
+  <meta name="flags" content="dom" />
+  <meta name="assert"
+        content="Tests that run-ins run in if text is dynamically set to
+                 whitespace between them and the block."/>
+  <style type="text/css"><![CDATA[
+    div { display: block; }
+    .run-in { display: run-in; font-weight: bold }
+    #target { border: 2px solid black; }
+  ]]></style>
+  <script type="text/javascript"><![CDATA[
+    function flushLayout(elt) {
+      elt.offsetWidth; /* Just undefined on non-elements, but that's ok */
+      for (var i = 0; i < elt.childNodes.length; ++i) {
+        flushLayout(elt.childNodes[i]);
+      }
+    }
+    window.onload = function() {
+      flushLayout(document.documentElement);
+      var t = document.getElementById("target");
+      t.previousSibling.data = "  ";
+    }
+  ]]></script>
+ </head>
+ <body>
+   <div class="run-in">Run-in header</div>
+   Some text.
+   <div id="target">Start of block.  The run-in header should be inside the
+    border around this block and there should be no space between the word
+    "header" and the word "Start".</div>
+ </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/run-in-text-ref.xht b/testing/web-platform/tests/css/css-display/run-in/run-in-text-ref.xht
new file mode 100644
index 0000000000..88f4930b4a
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/run-in-text-ref.xht
@@ -0,0 +1,19 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+  <head>
+    <title>CSS Reftest Reference</title>
+    <link rel="author" title="Boris Zbarsky" href="mailto:bzbarsky@mit.edu"/>
+    <link rel="reviewer" title="Microsoft" href="http://www.microsoft.com/" />
+    <style type="text/css">
+      .run-in { font-weight: bold }
+      #target { border: 2px solid black; }
+    </style>
+  </head>
+  <body>
+    <div class="run-in">Run-in header</div>
+    <div>Some text.</div>
+    <div id="target">Start of block.  The run-in header should NOT be inside
+    the border around this block; it should be on a line by itself before the
+    line containing "Some text".</div>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/support/black15x15.png b/testing/web-platform/tests/css/css-display/run-in/support/black15x15.png
new file mode 100644
index 0000000000..b1bbef2cd5
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/support/black15x15.png
diff --git a/testing/web-platform/tests/css/css-display/run-in/support/blue15x15.png b/testing/web-platform/tests/css/css-display/run-in/support/blue15x15.png
new file mode 100644
index 0000000000..89de32fdb8
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/support/blue15x15.png
diff --git a/testing/web-platform/tests/css/css-display/run-in/support/blue96x96.png b/testing/web-platform/tests/css/css-display/run-in/support/blue96x96.png
new file mode 100644
index 0000000000..820f8cace2
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/support/blue96x96.png
diff --git a/testing/web-platform/tests/css/css-display/run-in/support/green15x15.png b/testing/web-platform/tests/css/css-display/run-in/support/green15x15.png
new file mode 100644
index 0000000000..51741584a0
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/support/green15x15.png
diff --git a/testing/web-platform/tests/css/css-display/run-in/support/swatch-blue.png b/testing/web-platform/tests/css/css-display/run-in/support/swatch-blue.png
new file mode 100644
index 0000000000..bf2759634d
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/support/swatch-blue.png
diff --git a/testing/web-platform/tests/css/css-display/run-in/table-anonymous-block-001.xht b/testing/web-platform/tests/css/css-display/run-in/table-anonymous-block-001.xht
new file mode 100644
index 0000000000..c2e8b69549
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/table-anonymous-block-001.xht
@@ -0,0 +1,33 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: The anonymous block box around a table does not work with run-in interaction</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/tables.html#model" />
+        <meta name="assert" content="The anonymous block around a table does not behave like a block for 'run-in' interaction." />
+        <style type="text/css">
+            div
+            {
+                display: run-in;
+            }
+            table
+            {
+                background: black;
+            }
+            td
+            {
+                height: 100px;
+                width: 100px;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the "Filler Text" is above the box.</p>
+        <div>Filler Text</div>
+        <table>
+            <tr>
+                <td></td>
+            </tr>
+        </table>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/table-layout-applies-to-004.xht b/testing/web-platform/tests/css/css-display/run-in/table-layout-applies-to-004.xht
new file mode 100644
index 0000000000..f7da9e08dd
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/table-layout-applies-to-004.xht
@@ -0,0 +1,59 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Table-layout and 'display: run-in' elements</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/tables.html#propdef-table-layout" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/tables.html#width-layout" />
+        <meta name="flags" content="ahem" />
+        <meta name="assert" content="Table-layout does not apply to 'display: run-in' elements." />
+        <link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
+        <style type="text/css">
+            #test
+            {
+                display: run-in;
+                table-layout: fixed;
+                width: 10em;
+            }
+            .colgroup
+            {
+                display: table-column-group;
+                width: 5em;
+            }
+            .tr
+            {
+                display: table-row;
+            }
+            .td
+            {
+                background: black;
+                display: table-cell;
+                font: 1em Ahem;
+                overflow: hidden;
+                padding: 0;
+            }
+            #reference
+            {
+                background: blue;
+                height: 2em;
+                width: 20em;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if both bars below are the same width.</p>
+        <div id="test">
+            <div class="colgroup"></div>
+            <div class="colgroup"></div>
+            <div class="tr">
+                <div class="td">XXXXX</div>
+                <div class="td">XXXXX</div>
+            </div>
+            <div class="tr">
+                <div class="td">XXXXXXXXX0</div>
+                <div class="td">XXXXXXXXX0</div>
+            </div>
+        </div>
+        <div id="reference"></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/text-align-applies-to-004.xht b/testing/web-platform/tests/css/css-display/run-in/text-align-applies-to-004.xht
new file mode 100644
index 0000000000..cb5fc309e5
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/text-align-applies-to-004.xht
@@ -0,0 +1,22 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Text-align application on a 'display: run-in' element</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/text.html#propdef-text-align" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/text.html#alignment-prop" />
+        <meta name="assert" content="The 'text-align' property is applied ton 'display: run-in' elements." />
+        <style type="text/css">
+            div
+            {
+                border: solid;
+                display: run-in;
+                text-align: right;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the "Filler Text" below is aligned to the right side of the box.</p>
+        <div>Filler Text Filler Text Filler Text Filler Text</div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/text-decoration-applies-to-004.xht b/testing/web-platform/tests/css/css-display/run-in/text-decoration-applies-to-004.xht
new file mode 100644
index 0000000000..7efedf6ad9
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/text-decoration-applies-to-004.xht
@@ -0,0 +1,22 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Text-decoration application on a 'run-in' element</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/text.html#propdef-text-decoration" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/text.html#lining-striking-props" />
+        <link rel="match" href="../../reference/pass_if_filler_text_underlined.html"/>
+        <meta name="assert" content="The 'text-decoration' property applies to a 'run-in' element." />
+        <style type="text/css">
+            div
+            {
+                display: run-in;
+                text-decoration: underline;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the "Filler Text" below has a line under it.</p>
+        <div>Filler Text</div>
+    </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/text-indent-applies-to-004.xht b/testing/web-platform/tests/css/css-display/run-in/text-indent-applies-to-004.xht
new file mode 100644
index 0000000000..a7bce70d29
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/text-indent-applies-to-004.xht
@@ -0,0 +1,37 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Text-indent application on a 'display: run-in' element</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/text.html#propdef-text-indent" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/text.html#indentation-prop" />
+        <meta name="flags" content="ahem" />
+        <meta name="assert" content="The 'text-indent' property is applied to 'display: run-in' elements." />
+        <link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
+        <style type="text/css">
+            div
+            {
+                font: 16px/1em Ahem;
+            }
+            div div
+            {
+                display: run-in;
+                text-indent: 10em;
+            }
+            #div1
+            {
+                background: blue;
+                height: 1em;
+                margin-left: 10em;
+                width: 5em;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the black box below is directly above the blue box. (Note that the two boxes do not need to be touching.)</p>
+        <div>
+            <div>XXXXX</div>
+        </div>
+        <div id="div1"></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/text-transform-applies-to-004.xht b/testing/web-platform/tests/css/css-display/run-in/text-transform-applies-to-004.xht
new file mode 100644
index 0000000000..8b5e2af0ca
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/text-transform-applies-to-004.xht
@@ -0,0 +1,22 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Text-transform application to 'display: run-in' element</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/text.html#propdef-text-transform" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/text.html#caps-prop" />
+        <link rel="match" href="../../reference/pass_if_letter_uppercase.html" />
+        <meta name="assert" content="The 'text-transform' property is applied to 'display: run-in' elements." />
+        <style type="text/css">
+            div
+            {
+                display: run-in;
+                text-transform: capitalize;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the letter "F" in the words "Filler Text" below is in upper-case.</p>
+        <div>filler text</div>
+    </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/top-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/top-applies-to-011.xht
new file mode 100644
index 0000000000..618b75e86d
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/top-applies-to-011.xht
@@ -0,0 +1,30 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Top applied to element with 'display' set to run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#propdef-top" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#dis-pos-flo" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#position-props" />
+        <meta name="assert" content="The 'top' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                background: green;
+                top: 0;
+                display: run-in;
+                height: 1in;
+                position: absolute;
+                width: 1in;
+            }
+            p
+            {
+                margin-top: 1.5in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a box at the top of the page.</p>
+        <div></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/unicode-bidi-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/unicode-bidi-applies-to-011.xht
new file mode 100644
index 0000000000..575de0e2a0
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/unicode-bidi-applies-to-011.xht
@@ -0,0 +1,22 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Unicode-bidi applied to element with 'display' set to run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#propdef-unicode-bidi" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#direction" />
+        <meta name="assert" content="The 'unicode-bidi' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            div
+            {
+                direction: rtl;
+                display: run-in;
+                unicode-bidi: bidi-override;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there are the words "PASS PASS" below.</p>
+        <div>SSAP SSAP</div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/vertical-align-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/vertical-align-applies-to-011.xht
new file mode 100644
index 0000000000..f27cc0693b
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/vertical-align-applies-to-011.xht
@@ -0,0 +1,28 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Vertical-align applied to elements with 'display' set to 'run-in'</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visudet.html#propdef-vertical-align" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visudet.html#leading" />
+        <meta name="flags" content="ahem" />
+        <meta name="assert" content="The 'vertical-align' property does not apply to elements with 'display' set to 'run-in'." />
+        <link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
+        <style type="text/css">
+            div
+            {
+                background: orange;
+                color: blue;
+                display: run-in;
+                font: 20px/1em Ahem;
+                height: 1in;
+                vertical-align: bottom;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if the blue box below is in the upper-left corner of the orange box.</p>
+        <div>X</div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/visibility-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/visibility-applies-to-011.xht
new file mode 100644
index 0000000000..85a1aa8e3f
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/visibility-applies-to-011.xht
@@ -0,0 +1,32 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Visibility applied to elements with 'display' set to 'run-in'</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visufx.html#propdef-visibility" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visufx.html#visibility" />
+        <meta name="assert" content="The 'visibility' property applies to elements with 'display' set to 'run-in'." />
+        <style type="text/css">
+            #div1
+            {
+                background: red;
+                display: run-in;
+                height: 1in;
+                visibility: hidden;
+                width: 1in;
+            }
+            .box
+            {
+                background: black;
+                height: 1em;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is white space between the boxes below and there is no red visible on the page.</p>
+        <div class="box"></div>
+        <div id="div1"><div></div></div>
+        <div class="box"></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/white-space-applies-to-004.xht b/testing/web-platform/tests/css/css-display/run-in/white-space-applies-to-004.xht
new file mode 100644
index 0000000000..ce9820ff30
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/white-space-applies-to-004.xht
@@ -0,0 +1,39 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: White-space application to 'display: run-in' element</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/text.html#propdef-white-space" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/text.html#white-space-prop" />
+        <meta name="flags" content="ahem" />
+        <meta name="assert" content="The 'white-space' property applies to 'display: run-in' elements." />
+        <link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
+        <style type="text/css">
+            div
+            {
+                font: 16px/1em Ahem;
+            }
+            #div1
+            {
+                display: run-in;
+                white-space: pre;
+            }
+            #div2, #div3
+            {
+                background: black;
+                display: inline-block;
+                height: 1em;
+                width: 2em;
+            }
+            #div3
+            {
+                margin-left: 3em;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there are only two boxes below.</p>
+        <div id="div1">XX   XX</div>
+        <div id="div2"></div><div id="div3"></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/width-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/width-applies-to-011.xht
new file mode 100644
index 0000000000..fcf32f426b
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/width-applies-to-011.xht
@@ -0,0 +1,24 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Width applied to elements with 'display' set to 'run-in'</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visudet.html#propdef-width" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visudet.html#the-width-property" />
+        <link rel="match" href="../../reference/pass_if_square_96px_black.html"/>
+        <meta name="assert" content="The 'width' property applies to elements with 'display' set to 'run-in'." />
+        <style type="text/css">
+            div
+            {
+                background: black;
+                display: run-in;
+                height: 1in;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is a square below.</p>
+        <div></div>
+    </body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/run-in/word-spacing-applies-to-004.xht b/testing/web-platform/tests/css/css-display/run-in/word-spacing-applies-to-004.xht
new file mode 100644
index 0000000000..2996691015
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/word-spacing-applies-to-004.xht
@@ -0,0 +1,36 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Word-spacing application to 'display: run-in' element</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/text.html#propdef-word-spacing" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/text.html#spacing-props" />
+        <meta name="flags" content="ahem" />
+        <meta name="assert" content="The 'word-spacing' property applies to 'display: run-in' elements." />
+        <link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
+        <style type="text/css">
+            div
+            {
+                font: 16px/1em Ahem;
+            }
+            div div
+            {
+                display: run-in;
+                word-spacing: 10em;
+            }
+            #div1
+            {
+                background: blue;
+                height: 1em;
+                width: 22em;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there are two black boxes below and the last black box ends when the blue box ends.</p>
+        <div>
+            <div>XXXXX XXXXXX</div>
+        </div>
+        <div id="div1"></div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/run-in/z-index-applies-to-011.xht b/testing/web-platform/tests/css/css-display/run-in/z-index-applies-to-011.xht
new file mode 100644
index 0000000000..b8e02fae75
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/run-in/z-index-applies-to-011.xht
@@ -0,0 +1,36 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>CSS Test: Z-index applied to element with 'display' set to run-in</title>
+        <link rel="author" title="Microsoft" href="http://www.microsoft.com/" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#propdef-z-index" />
+        <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#z-index" />
+        <meta name="assert" content="The 'z-index' property applies to elements with a display of run-in." />
+        <style type="text/css">
+            #div2
+            {
+                background: green;
+                display: run-in;
+                z-index: 1;
+            }
+            #zindex
+            {
+                background: red;
+                top: -1in;
+            }
+            #div2, #zindex
+            {
+                height: 1in;
+                position: relative;
+                width: 1in;
+            }
+        </style>
+    </head>
+    <body>
+        <p>Test passes if there is no red visible on the page.</p>
+        <div>
+            <div id="div2"><div></div></div>
+            <div id="zindex"></div>
+        </div>
+    </body>
+</html>
+\ No newline at end of file
diff --git a/testing/web-platform/tests/css/css-display/select-4-option-optgroup-display-none-ref.html b/testing/web-platform/tests/css/css-display/select-4-option-optgroup-display-none-ref.html
new file mode 100644
index 0000000000..230c8a6d4f
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/select-4-option-optgroup-display-none-ref.html
@@ -0,0 +1,41 @@
+<!DOCTYPE HTML>
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<html><head>
+  <meta charset="utf-8">
+  <title>Reference: display:none on OPTION and OPTGROUP</title>
+  <link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+  <style>
+
+.none { display:none; }
+.contents { display:contents; }
+.red { color: red; }
+.green { color: green; }
+
+select { -webkit-appearance: none; }
+
+  </style>
+</head>
+<body>
+
+<pre>FAIL if there is any red color</pre>
+
+<optgroup></optgroup>
+<optgroup class="contents red"></optgroup>
+<optgroup class="contents green" label="optgroup"></optgroup>
+
+<br>
+
+<select class="red" size="4"></select>
+<select size="4" class="red"></select>
+<select size="4" class="red"></select>
+<select size="4" class="red"><optgroup></select>
+<select size="4"></select>
+<select size="4" class="red"></select>
+<select size="4" class="red"></select>
+<select size="4" class="red"></select>
+
+</body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/select-4-option-optgroup-display-none.html b/testing/web-platform/tests/css/css-display/select-4-option-optgroup-display-none.html
new file mode 100644
index 0000000000..a6da3d53c7
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/select-4-option-optgroup-display-none.html
@@ -0,0 +1,48 @@
+<!DOCTYPE HTML>
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<html><head>
+  <meta charset="utf-8">
+  <title>CSS Test: display:none on OPTION and OPTGROUP</title>
+  <link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
+  <link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-none">
+  <link rel="match" href="select-4-option-optgroup-display-none-ref.html">
+  <style>
+
+.none { display:none; }
+.contents { display:contents; }
+.red { color: red; }
+.green { color: green; }
+
+select { -webkit-appearance: none; }
+
+  </style>
+</head>
+<body>
+
+<pre>FAIL if there is any red color</pre>
+
+<option class="none red">text</option>
+<optgroup class="none red">text</optgroup>
+
+<optgroup class="none red"><option>option</option></optgroup>
+<optgroup><option class="none red">option</option></optgroup>
+<optgroup class="contents red"><option class="none">option</option></optgroup>
+<optgroup class="contents green" label="optgroup"><option class="none red">option</option></optgroup>
+<optgroup class="none red" label="optgroup"><option class="red">option</option></optgroup>
+
+<br>
+
+<select class="red" size="4">select</select>
+<select size="4" class="red"><optgroup class="none" label="optgroup"></select>
+<select size="4" class="red"><option class="none">option</select>
+<select size="4" class="red"><optgroup><option class="none">option</select>
+<select size="4"><optgroup class="none"><option class="green">option</select>
+<select size="4" class="red"><optgroup class="none green" label="optgroup"><option>option</select>
+<select size="4" class="red"><optgroup class="none"><option class="none">option</select>
+<select size="4" class="red"><optgroup class="none green" label="optgroup"><option class="none">option</select>
+
+</body>
+</html>
diff --git a/testing/web-platform/tests/css/css-display/support/acid.css b/testing/web-platform/tests/css/css-display/support/acid.css
new file mode 100644
index 0000000000..62d1aca2e5
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/support/acid.css
@@ -0,0 +1,59 @@
+html, body {
+  color: black;
+  background-color: white;
+  font-size: 16px;
+  padding: 0;
+  margin: 0;
+}
+
+body { color: red; }
+
+.table {
+  display: table;
+  border-collapse: collapse;
+  border: blue solid 1pt;
+}
+
+.itable { display: inline-table; }
+.caption { display: table-caption; }
+.cell {
+  display: table-cell;
+  border: inherit;
+}
+.row {
+  display: table-row;
+  border: green dashed 1pt;
+}
+.rowg { display: table-row-group; }
+.head { display: table-header-group; }
+.foot { display: table-footer-group; }
+.col { display: table-column; }
+.colg { display: table-column-group; }
+.flex { display: flex; }
+.iflex { display: inline-flex; }
+.li { display: list-item; }
+.ib { display: inline-block; }
+.inline { display: inline; }
+.columns { columns: 2; height: 4em; }
+.contents {
+  display: contents;
+  align-items: inherit;
+  justify-items:inherit;
+}
+.c1 { color: lime; }
+.c2 { background: blue; color: pink; }
+.c3 { color: teal; }
+.c4 { color: green; }
+.c5 { color: silver; }
+.c6 { color: cyan; }
+.c7 { color: magenta; }
+.c8 { color: yellow; }
+.c9 { color: grey; }
+.c10{ color: black; }
+.b { background: inherit; }
+
+/** This is the only difference between references and non-reference styles */
+.ref .c2 { background: transparent; }
+.ref .b { background:blue; }
+.ref div.contents { display: block; }
+.ref span.contents { display: inline; }
diff --git a/testing/web-platform/tests/css/css-display/support/red-square.html b/testing/web-platform/tests/css/css-display/support/red-square.html
new file mode 100644
index 0000000000..e4e48ccfdc
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/support/red-square.html
@@ -0,0 +1,5 @@
+<!DOCTYPE html>
+<style>
+  body { margin:0; }
+</style>
+<div id="square" style="width:100px; height:100px; background:red;"></div>
diff --git a/testing/web-platform/tests/css/css-display/support/swatch-orange.png b/testing/web-platform/tests/css/css-display/support/swatch-orange.png
new file mode 100644
index 0000000000..d3cd498b52
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/support/swatch-orange.png
diff --git a/testing/web-platform/tests/css/css-display/support/util.js b/testing/web-platform/tests/css/css-display/support/util.js
new file mode 100644
index 0000000000..08024b52d5
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/support/util.js
@@ -0,0 +1,23 @@
+function eachDisplayContentsElementIn(document, window, callbackDo, callbackUndo) {
+  var elements = [];
+
+  document.body.offsetHeight;
+
+  // NOTE: Doing qsa('*') and getComputedStyle is just for the
+  // test's sake, since it's easier to mess it up when
+  // getComputedStyle is involved.
+  var all = document.querySelectorAll('*');
+  for (var i = 0; i < all.length; ++i) {
+    if (window.getComputedStyle(all[i]).display === "contents") {
+      callbackDo(all[i]);
+      elements.push(all[i]);
+    }
+  }
+
+  document.body.offsetHeight;
+
+  for (var i = 0; i < elements.length; ++i)
+    callbackUndo(elements[i]);
+
+  document.body.offsetHeight;
+}
diff --git a/testing/web-platform/tests/css/css-display/textarea-display.html b/testing/web-platform/tests/css/css-display/textarea-display.html
new file mode 100644
index 0000000000..44634e3c3b
--- /dev/null
+++ b/testing/web-platform/tests/css/css-display/textarea-display.html
@@ -0,0 +1,22 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>Display of textarea</title>
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1700535">
+<link rel="help" href="https://github.com/whatwg/html/issues/4082">
+<meta name="assert" content="textarea has inline block display.">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+</head>
+<body>
+<textarea id="t"></textarea>
+<script>
+    test(
+      function(){
+        var target = document.getElementById("t");
+        assert_equals(getComputedStyle(target).display, "inline-block");
+      }, "textarea has inline block display");
+</script>
+</body>
+</html>
author	Daniel Baumann <daniel.baumann@progress-linux.org>	2024-04-19 00:47:55 +0000
committer	Daniel Baumann <daniel.baumann@progress-linux.org>	2024-04-19 00:47:55 +0000
commit	26a029d407be480d791972afb5975cf62c9360a6 (patch)
tree	f435a8308119effd964b339f76abb83a57c29483 /testing/web-platform/tests/css/css-display
parent	Initial commit. (diff)
download	firefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz firefox-26a029d407be480d791972afb5975cf62c9360a6.zip