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Merged
juanmaguitar merged 2 commits into from
Feb 23, 2026
Merged

Add CharacterReferenceEquivalenceTest #2

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6d66154
Add CharacterReferenceEquivalenceTest
juanmaguitar Feb 23, 2026
ba2f35b
Merge branch 'main' into add/character-reference-equivalence-test
juanmaguitar Feb 23, 2026
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82 changes: 82 additions & 0 deletions tests/CharacterReferenceEquivalenceTest.php
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<?php
/**
* Tests demonstrating assertEqualHTML's HTML character reference normalization.
*
* Any given character has multiple valid representations in HTML: a literal
* character, a named reference (&not;), a decimal reference (&#172;), a
* padded decimal (&#0172;), a hex reference (&#xAC;), a padded hex
* (&#x0000AC;), or even a named reference without a semicolon (&not).
* assertEqualHTML treats all of them as equivalent. assertSame does not.
*
* @package AssertEqualHTMLExamples
*/

class CharacterReferenceEquivalenceTest extends WP_UnitTestCase {

/**
* Demonstrates why assertSame is fragile for HTML character references.
*
* The NOT SIGN (¬, U+00AC) can be encoded as &not; or &#172; or &#xAC;,
* among others. To assertSame, those strings look completely different even
* though every browser renders them identically.
*
* This test is marked skipped so the suite stays green.
* Comment out markTestSkipped() to see it fail.
*/
public function test_assertsame_fails_for_character_references(): void {
$this->markTestSkipped(
'Intentionally skipped. Remove markTestSkipped() to see how assertSame ' .
'fails when the same character is encoded differently.'
);

$expected = '<meta name="&not;">';
$actual = '<meta name="&#172;">';

// ❌ This will fail even though both encode the same character (¬).
$this->assertSame( $expected, $actual );
}

/**
* assertEqualHTML normalizes all representations of a character to the same
* value before comparing, so every encoding of ¬ (U+00AC) is equivalent.
*
* Representations covered:
* - Literal UTF-8 character
* - Named reference: &not;
* - Decimal reference: &#172;
* - Padded decimal reference: &#0172;
* - Hex reference: &#xAC;
* - Padded hex reference: &#x0000AC;
* - Named reference without semicolon: &not
*/
public function test_all_character_reference_forms_are_equivalent(): void {
$expected = <<<HTML
<meta
not-literal="¬"
not-named="¬"
not-decimal="¬"
not-decimal-padded="¬"
not-hex="¬"
not-hex-padded="¬"
also-not="¬"
>
HTML;

$actual = <<<HTML
<meta
not-literal="¬"
not-named="&not;"
not-decimal="&#172;"
not-decimal-padded="&#0172;"
not-hex="&#xAC;"
not-hex-padded="&#x0000AC;"
also-not="&not"
>
HTML;

// ✅ Passes because assertEqualHTML decodes all character references
// before comparing — literal, named, decimal, hex, with or without
// a trailing semicolon.
$this->assertEqualHTML( $expected, $actual );
}
}