Reimplement main aspect of assertEqualXMLStructure

src/Framework/Assert.php

@@ -2251,6 +2251,27 @@
         static::assertNotEquals($expected, $actual, $message);
     }
 
+    public static function assertDOMTreesEqualStructurally(DOMElement $expectedElement, DOMElement $actualElement, bool $keepComments = false, string $message = ''): void
+    {
+        $ed = new DOMDocument();
+        $ed->appendChild($ed->importNode($expectedElement, true));
+        $xmlStr = $ed->C14N(false, $keepComments);
+
+        $ed->preserveWhiteSpace = false;
+        $ed->loadXML($xmlStr);
+        $ed->formatOutput = true;
+
+        $ad = new DOMDocument();
+        $ad->appendChild($ad->importNode($actualElement, true));
+        $xmlStr = $ad->C14N(false, $keepComments);
+
+        $ad->preserveWhiteSpace = false;
+        $ad->loadXML($xmlStr);
+        $ad->formatOutput = true;
+
+        self::assertEquals($ed->documentElement, $ad->documentElement, $message);
+    }
+
     /**
      * Asserts that a hierarchy of DOMElements matches.
      *

src/Framework/Assert/Functions.php

@@ -2422,6 +2422,23 @@ function assertXmlStringNotEqualsXmlString($expectedXml, $actualXml, string $mes
     }
 }
 
+if (!function_exists('PHPUnit\Framework\assertDOMTreesEqualStructurally')) {
+    /**
+     * Asserts that two DOM trees are structurally identical.
+     *
+     * @throws AssertionFailedError
+     * @throws ExpectationFailedException
+     *
+     * @no-named-arguments Parameter names are not covered by the backward compatibility promise for PHPUnit
+     *
+     * @see Assert::assertDOMTreesEqualStructurally
+     */
+    function assertDOMTreesEqualStructurally(DOMElement $expectedElement, DOMElement $actualElement, bool $keepComments = false, string $message = ''): void
+    {
+        Assert::assertDOMTreesEqualStructurally(...func_get_args());
+    }
+}
+
 if (!function_exists('PHPUnit\Framework\assertEqualXMLStructure')) {
     /**
      * Asserts that a hierarchy of DOMElements matches.