WordPress · sirreal · Jul 3, 2026 · Jul 3, 2026 · Jul 3, 2026 · Jul 3, 2026
diff --git a/.github/workflows/phpunit-tests.yml b/.github/workflows/phpunit-tests.yml
@@ -252,7 +252,7 @@ jobs:
         php: [ '7.4', '8.0', '8.4' ]
         db-type: [ 'mysql' ]
         db-version: [ '8.4' ]
-        phpunit-test-groups: [ 'html-api-html5lib-tests' ]
+        phpunit-test-groups: [ 'html-api-web-platform-tests' ]
         # A matrix value is needed in the 'name' directive for proper grouping in the GitHub UI.
         label: [ 'HTML API' ]
     with:
@@ -305,7 +305,7 @@ jobs:
           - php: '8.4'
             db-version: '9.7'
             db-type: 'mysql'
-            phpunit-test-groups: 'html-api-html5lib-tests'
+            phpunit-test-groups: 'html-api-web-platform-tests'
 
         exclude:
           # Exclude PHP versions that are not supported by the database versions.

diff --git a/phpunit.xml.dist b/phpunit.xml.dist
@@ -29,7 +29,7 @@
 			<group>ms-files</group>
 			<group>ms-required</group>
 			<group>external-http</group>
-			<group>html-api-html5lib-tests</group>
+			<group>html-api-web-platform-tests</group>
 		</exclude>
 	</groups>
 	<logging>

diff --git a/tests/phpunit/data/html5lib-tests/AUTHORS.rst b/tests/phpunit/data/html5lib-tests/AUTHORS.rst
diff --git a/tests/phpunit/data/html5lib-tests/LICENSE b/tests/phpunit/data/html5lib-tests/LICENSE
diff --git a/tests/phpunit/data/html5lib-tests/README.md b/tests/phpunit/data/html5lib-tests/README.md
diff --git a/...hpunit/data/html5lib-tests/.gitattributes → ...it/data/web-platform-tests/.gitattributes b/...hpunit/data/html5lib-tests/.gitattributes → ...it/data/web-platform-tests/.gitattributes
diff --git a/tests/phpunit/data/web-platform-tests/LICENSE.md b/tests/phpunit/data/web-platform-tests/LICENSE.md
@@ -0,0 +1,11 @@
+# The 3-Clause BSD License
+
+Copyright © web-platform-tests contributors
+
+Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
+2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
+3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/tests/phpunit/data/web-platform-tests/README.md b/tests/phpunit/data/web-platform-tests/README.md
@@ -0,0 +1,19 @@
+# Web Platform Tests
+
+This directory contains a third-party test suite used for testing the WordPress HTML API.
+
+The tests are maintained by the Web Platform Tests project.
+The current tests can be found on GitHub at
+[`web-platform-tests/wpt/html/syntax/parsing/resources`](https://github.com/web-platform-tests/wpt/tree/master/html/syntax/parsing/resources).
+
+The version of the WPT files was taken from the git commit with
+SHA [`f4c2ec1d071ccbae305f7aea4e883b5bd0f5c0df`](https://github.com/web-platform-tests/wpt/commit/f4c2ec1d071ccbae305f7aea4e883b5bd0f5c0df).
+
+## Updating
+
+If there have been changes to the Web Platform Tests repository, this test suite can be updated. In
+order to update:
+
+1. Check out the latest version of git repository mentioned above.
+1. Replace the local `html_syntax_parsing_resources/` directory with the WPT repo's `html/syntax/parsing/resources` directory.
+1. Update the SHA mentioned in this README file with the new Web Platform Tests SHA.
diff --git a/...tml5lib-tests/tree-construction/README.md → ...s/html_syntax_parsing_resources/README.md b/...tml5lib-tests/tree-construction/README.md → ...s/html_syntax_parsing_resources/README.md
@@ -31,7 +31,7 @@ errors.
 
 Then there \*may\* be a line that says "\#document-fragment", which must
 be followed by a newline (LF), followed by a string of characters that
-indicates the context element, followed by a newline (LF). If the string 
+indicates the context element, followed by a newline (LF). If the string
 of characters starts with "svg ", the context element is in the SVG
 namespace and the substring after "svg " is the local name. If the
 string of characters starts with "math ", the context element is in the
@@ -67,9 +67,7 @@ per parent node that the node has before the root document node.
     double-quotes, another space an the system id in double-quotes, and
     then in any case "`>`".
 -   Processing instructions must be "`<?`", then the target, then a
-    space, then the data and then "`>`". (The HTML parser cannot emit
-    processing instructions, but scripts can, and the WebVTT to DOM
-    rules can emit them.)
+    space, then the data and then "`?>`".
 -   Template contents are represented by the string "content" with the
     children below it.
 

diff --git a/...ib-tests/tree-construction/adoption01.dat → ...l_syntax_parsing_resources/adoption01.dat b/...ib-tests/tree-construction/adoption01.dat → ...l_syntax_parsing_resources/adoption01.dat
diff --git a/...ib-tests/tree-construction/adoption02.dat → ...l_syntax_parsing_resources/adoption02.dat b/...ib-tests/tree-construction/adoption02.dat → ...l_syntax_parsing_resources/adoption02.dat
@@ -37,3 +37,20 @@
 |       <address>
 |         <a>
 |         <a>
+
+#data
+<nobr><table><marquee></table><nobr>
+#errors
+(1,6): expected-doctype-but-got-start-tag
+(1,22): unexpected-start-tag-implies-table-voodoo
+(1,30): end-tag-too-early-named
+(1,36): unexpected-start-tag-implies-end-tag
+(1,36): expected-closing-tag-but-got-eof
+#document
+| <html>
+|   <head>
+|   <body>
+|     <nobr>
+|       <marquee>
+|       <table>
+|     <nobr>
diff --git a/...ml5lib-tests/tree-construction/blocks.dat → .../html_syntax_parsing_resources/blocks.dat b/...ml5lib-tests/tree-construction/blocks.dat → .../html_syntax_parsing_resources/blocks.dat
diff --git a/...ib-tests/tree-construction/comments01.dat → ...l_syntax_parsing_resources/comments01.dat b/...ib-tests/tree-construction/comments01.dat → ...l_syntax_parsing_resources/comments01.dat
diff --git a/...lib-tests/tree-construction/doctype01.dat → ...ml_syntax_parsing_resources/doctype01.dat b/...lib-tests/tree-construction/doctype01.dat → ...ml_syntax_parsing_resources/doctype01.dat
diff --git a/...-tests/tree-construction/domjs-unsafe.dat → ...syntax_parsing_resources/domjs-unsafe.dat b/...-tests/tree-construction/domjs-unsafe.dat → ...syntax_parsing_resources/domjs-unsafe.dat
diff --git a/...ib-tests/tree-construction/entities01.dat → ...l_syntax_parsing_resources/entities01.dat b/...ib-tests/tree-construction/entities01.dat → ...l_syntax_parsing_resources/entities01.dat
diff --git a/...ib-tests/tree-construction/entities02.dat → ...l_syntax_parsing_resources/entities02.dat b/...ib-tests/tree-construction/entities02.dat → ...l_syntax_parsing_resources/entities02.dat
diff --git a/...ts/tree-construction/foreign-fragment.dat → ...ax_parsing_resources/foreign-fragment.dat b/...ts/tree-construction/foreign-fragment.dat → ...ax_parsing_resources/foreign-fragment.dat
diff --git a/...tests/tree-construction/html5test-com.dat → ...yntax_parsing_resources/html5test-com.dat b/...tests/tree-construction/html5test-com.dat → ...yntax_parsing_resources/html5test-com.dat
@@ -134,7 +134,7 @@
 #new-errors
 (1:2) unexpected-question-mark-instead-of-tag-name
 #document
-| <!-- ?import namespace="foo" implementation="#bar" -->
+| <?import namespace="foo" implementation="#bar"?>
 | <html>
 |   <head>
 |   <body>

diff --git a/...5lib-tests/tree-construction/inbody01.dat → ...tml_syntax_parsing_resources/inbody01.dat b/...5lib-tests/tree-construction/inbody01.dat → ...tml_syntax_parsing_resources/inbody01.dat
diff --git a/...l5lib-tests/tree-construction/isindex.dat → ...html_syntax_parsing_resources/isindex.dat b/...l5lib-tests/tree-construction/isindex.dat → ...html_syntax_parsing_resources/isindex.dat
diff --git a/...-tests/tree-construction/main-element.dat → ...syntax_parsing_resources/main-element.dat b/...-tests/tree-construction/main-element.dat → ...syntax_parsing_resources/main-element.dat
diff --git a/...html5lib-tests/tree-construction/math.dat → ...ts/html_syntax_parsing_resources/math.dat b/...html5lib-tests/tree-construction/math.dat → ...ts/html_syntax_parsing_resources/math.dat
diff --git a/...ts/tree-construction/menuitem-element.dat → ...ax_parsing_resources/menuitem-element.dat b/...ts/tree-construction/menuitem-element.dat → ...ax_parsing_resources/menuitem-element.dat
@@ -161,13 +161,14 @@
 #data
 <!DOCTYPE html><select><menuitem></select>
 #errors
-33: Stray start tag “menuitem”.
+1:34: ERROR: End tag 'select' isn't allowed here. Currently open tags: html, body, select, menuitem.
 #document
 | <!DOCTYPE html>
 | <html>
 |   <head>
 |   <body>
 |     <select>
+|       <menuitem>
 
 #data
 <!DOCTYPE html><option><menuitem>

diff --git a/...ee-construction/namespace-sensitivity.dat → ...rsing_resources/namespace-sensitivity.dat b/...ee-construction/namespace-sensitivity.dat → ...rsing_resources/namespace-sensitivity.dat
diff --git a/...ib-tests/tree-construction/noscript01.dat → ...l_syntax_parsing_resources/noscript01.dat b/...ib-tests/tree-construction/noscript01.dat → ...l_syntax_parsing_resources/noscript01.dat
diff --git a/...ending-spec-changes-plain-text-unsafe.dat → ...ending-spec-changes-plain-text-unsafe.dat b/...ending-spec-changes-plain-text-unsafe.dat → ...ending-spec-changes-plain-text-unsafe.dat
diff --git a/...ree-construction/pending-spec-changes.dat → ...arsing_resources/pending-spec-changes.dat b/...ree-construction/pending-spec-changes.dat → ...arsing_resources/pending-spec-changes.dat
diff --git a/...s/tree-construction/plain-text-unsafe.dat → ...x_parsing_resources/plain-text-unsafe.dat b/...s/tree-construction/plain-text-unsafe.dat → ...x_parsing_resources/plain-text-unsafe.dat