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joedolsonjoedolson
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Media: Test for DOMDocument before checking embedded alt text.
`DOMDocument` is not a required library for WordPress, and all other uses have validation via `class_exists`. Add a check to verify the library is available before attempting to use. Props smerriman, therssoftware, siliconforks, jorbin, joedolson. Fixes #66221. git-svn-id: https://develop.svn.wordpress.org/trunk@64089 602fd350-edb4-49c9-b593-d223f7449a82
1 parent e0fa2c9 commit cb186b3

2 files changed

Lines changed: 209 additions & 2 deletions

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‎src/wp-admin/includes/image.php‎

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@@ -1083,10 +1083,15 @@ function wp_read_image_metadata( $file ) {
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* @since 7.0.0
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*
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* @param string $file File path to the image.
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* @return string Embedded alternative text.
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* @return string Embedded alternative text, empty when there is no alt text or DOM extension is not installed.
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*/
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function wp_get_image_alttext( $file ) {
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$alt_text = '';
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$alt_text = '';
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if ( ! class_exists( 'DOMDocument', false ) ) {
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return $alt_text;
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}
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$img_contents = file_get_contents( $file );
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if ( false === $img_contents ) {

‎tests/phpunit/tests/image/alttext.php‎

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@@ -0,0 +1,202 @@
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<?php
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/**
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* Tests for wp_get_image_alttext().
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*
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* @group image
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* @group media
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* @ticket 66221
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*
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* @covers ::wp_get_image_alttext
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*/
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class Tests_Image_Alttext extends WP_UnitTestCase {
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/**
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* Temporary files to delete in tear_down().
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*
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* @var string[]
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*/
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private $temp_files = array();
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public function tear_down() {
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restore_current_locale();
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foreach ( $this->temp_files as $file ) {
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if ( file_exists( $file ) ) {
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unlink( $file );
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}
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}
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$this->temp_files = array();
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parent::tear_down();
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}
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/**
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* Creates a temporary file containing XMP metadata with the given alt text entries.
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*
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* @param array<string, string> $alt_entries Associative array where key is xml:lang and value is the alt text.
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* @return string File path to the temporary file.
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*/
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private function create_temp_xmp_file( array $alt_entries ) {
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$li_tags = '';
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foreach ( $alt_entries as $lang => $text ) {
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$li_tags .= "\t\t\t\t" . '<rdf:li xml:lang="' . esc_attr( $lang ) . '">' . htmlspecialchars( $text, ENT_XML1, 'UTF-8' ) . "</rdf:li>\n";
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}
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$content = "<x:xmpmeta xmlns:x=\"adobe:ns:meta/\">\n"
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. "\t<rdf:RDF xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\" xmlns:Iptc4xmpCore=\"http://iptc.org/std/Iptc4xmpCore/1.0/xmlns/\">\n"
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. "\t\t<rdf:Description>\n"
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. "\t\t\t<Iptc4xmpCore:AltTextAccessibility>\n"
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. "\t\t\t\t<rdf:Alt>\n"
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. $li_tags
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. "\t\t\t\t</rdf:Alt>\n"
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. "\t\t\t</Iptc4xmpCore:AltTextAccessibility>\n"
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. "\t\t</rdf:Description>\n"
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. "\t</rdf:RDF>\n"
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. '</x:xmpmeta>';
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$file = wp_tempnam( 'alttext-xmp' );
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file_put_contents( $file, $content );
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$this->temp_files[] = $file;
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return $file;
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}
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/**
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* Asserts that the alt text matches the expected value when the DOM extension is available,
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* or is empty when the DOM extension is not installed.
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*
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* @param string $expected Expected alt text when DOM is available.
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* @param string $actual Actual alt text returned by wp_get_image_alttext().
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* @param string $message Optional failure message.
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*/
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private function assert_alttext_matches_or_empty_without_dom( $expected, $actual, $message = '' ) {
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if ( ! class_exists( 'DOMDocument', false ) ) {
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$this->assertSame( '', $actual, 'Expected empty string when DOM extension is not available.' );
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return;
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}
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$this->assertSame( $expected, $actual, $message );
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}
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/**
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* Tests reading alt text with a valid image containing XMP metadata.
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*/
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public function test_wp_get_image_alttext_with_valid_image() {
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$alt = wp_get_image_alttext( DIR_TESTDATA . '/images/IPTC-PhotometadataRef-Std2025.1.jpg' );
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$this->assert_alttext_matches_or_empty_without_dom(
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'This is the Alt Text description to support accessibility in 2025.1',
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$alt
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);
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}
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/**
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* Tests wp_get_image_alttext() returns empty string when image has no XMP metadata.
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*/
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public function test_wp_get_image_alttext_returns_empty_when_no_xmp_metadata() {
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$alt = wp_get_image_alttext( DIR_TESTDATA . '/images/test-image-upside-down.jpg' );
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$this->assertSame( '', $alt );
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}
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/**
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* Tests wp_get_image_alttext() returns empty string when XMP has no AltTextAccessibility node.
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*/
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public function test_wp_get_image_alttext_returns_empty_when_no_alttext_node() {
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$file = wp_tempnam( 'alttext-no-node' );
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$content = '<x:xmpmeta xmlns:x="adobe:ns:meta/"><rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"><rdf:Description rdf:about="" /></rdf:RDF></x:xmpmeta>';
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file_put_contents( $file, $content );
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$this->temp_files[] = $file;
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$alt = wp_get_image_alttext( $file );
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$this->assertSame( '', $alt );
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}
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/**
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* Tests possibility 1: exact match on site locale.
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*/
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public function test_wp_get_image_alttext_exact_locale_match() {
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switch_to_locale( 'de_DE' );
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$file = $this->create_temp_xmp_file(
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array(
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'de_DE' => 'Deutscher Alt-Text (exakt)',
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'de' => 'Deutscher Alt-Text (teilweise)',
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'x-default' => 'Default Alt Text',
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)
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);
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$alt = wp_get_image_alttext( $file );
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$this->assert_alttext_matches_or_empty_without_dom( 'Deutscher Alt-Text (exakt)', $alt );
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}
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/**
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* Tests possibility 2: partial match on site locale (e.g. locale is es_ES and rdf:li has @xml:lang="es").
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*/
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public function test_wp_get_image_alttext_partial_locale_match() {
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switch_to_locale( 'es_ES' );
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$file = $this->create_temp_xmp_file(
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array(
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'es' => 'Texto alternativo en espanol (parcial)',
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'x-default' => 'Default Alt Text',
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)
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);
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$alt = wp_get_image_alttext( $file );
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$this->assert_alttext_matches_or_empty_without_dom( 'Texto alternativo en espanol (parcial)', $alt );
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}
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/**
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* Tests possibility 3: fallback to x-default when neither exact nor partial locale matches.
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*/
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public function test_wp_get_image_alttext_x_default_fallback() {
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switch_to_locale( 'ja_JP' );
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$file = $this->create_temp_xmp_file(
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array(
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'de_DE' => 'Deutscher Alt-Text',
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'x-default' => 'Default Alt Text Fallback',
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)
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);
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$alt = wp_get_image_alttext( $file );
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$this->assert_alttext_matches_or_empty_without_dom( 'Default Alt Text Fallback', $alt );
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}
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/**
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* Tests that wp_get_image_alttext() returns different alt text based on the site locale.
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*/
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public function test_wp_get_image_alttext_returns_different_alt_text_based_on_site_locale() {
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$file = $this->create_temp_xmp_file(
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array(
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'en_US' => 'English (US) description',
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'en_GB' => 'English (UK) description',
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'es_ES' => 'Descripcion en espanol',
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'de_DE' => 'Deutsche Beschreibung',
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'x-default' => 'Default description',
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)
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);
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switch_to_locale( 'en_US' );
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$this->assert_alttext_matches_or_empty_without_dom( 'English (US) description', wp_get_image_alttext( $file ) );
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switch_to_locale( 'en_GB' );
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$this->assert_alttext_matches_or_empty_without_dom( 'English (UK) description', wp_get_image_alttext( $file ) );
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switch_to_locale( 'es_ES' );
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$this->assert_alttext_matches_or_empty_without_dom( 'Descripcion en espanol', wp_get_image_alttext( $file ) );
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switch_to_locale( 'de_DE' );
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$this->assert_alttext_matches_or_empty_without_dom( 'Deutsche Beschreibung', wp_get_image_alttext( $file ) );
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// Unmatched locale should fall back to x-default.
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switch_to_locale( 'ja_JP' );
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$this->assert_alttext_matches_or_empty_without_dom( 'Default description', wp_get_image_alttext( $file ) );
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}
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}

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