WP_Site_Health::get_test_php_extensions

	 *
	 * @since 5.2.0
	 *
	 * @return array
	 */
	public function get_test_php_extensions() {
		$result = array(
			'label'       => __( 'Required and recommended modules are installed' ),
			'status'      => 'good',
			'badge'       => array(
				'label' => __( 'Performance' ),
				'color' => 'blue',
			),
			'description' => sprintf(
				'<p>%s</p><p>%s</p>',
				__( 'PHP modules perform most of the tasks on the server that make your site run. Any changes to these must be made by your server administrator.' ),
				sprintf(
					/* translators: 1: Link to the hosting group page about recommended PHP modules. 2: Additional link attributes. 3: Accessibility text. */
					__( 'The WordPress Hosting Team maintains a list of those modules, both recommended and required, in <a href="%1$s" %2$s>the team handbook%3$s</a>.' ),
					/* translators: Localized team handbook, if one exists. */
					esc_url( __( 'https://make.wordpress.org/hosting/handbook/handbook/server-environment/#php-extensions' ) ),
					'target="_blank" rel="noopener noreferrer"',
					sprintf(
						' <span class="screen-reader-text">%s</span><span aria-hidden="true" class="dashicons dashicons-external"></span>',
						/* translators: Accessibility text. */
						__( '(opens in a new tab)' )
					)
				)
			),
			'actions'     => '',
			'test'        => 'php_extensions',
		);

		$modules = array(
			'curl'      => array(
				'function' => 'curl_version',
				'required' => false,
			),
			'dom'       => array(
				'class'    => 'DOMNode',
				'required' => false,
			),
			'exif'      => array(
				'function' => 'exif_read_data',
				'required' => false,
			),
			'fileinfo'  => array(
				'function' => 'finfo_file',
				'required' => false,
			),
			'hash'      => array(
				'function' => 'hash',
				'required' => false,
			),
			'json'      => array(
				'function' => 'json_last_error',
				'required' => true,
			),
			'mbstring'  => array(
				'function' => 'mb_check_encoding',
				'required' => false,
			),
			'mysqli'    => array(
				'function' => 'mysqli_connect',
				'required' => false,
			),
			'libsodium' => array(
				'constant'            => 'SODIUM_LIBRARY_VERSION',
				'required'            => false,
				'php_bundled_version' => '7.2.0',
			),
			'openssl'   => array(
				'function' => 'openssl_encrypt',
				'required' => false,
			),
			'pcre'      => array(
				'function' => 'preg_match',
				'required' => false,
			),
			'imagick'   => array(
				'extension' => 'imagick',
				'required'  => false,
			),
			'mod_xml'   => array(
				'extension' => 'libxml',
				'required'  => false,
			),
			'zip'       => array(
				'class'    => 'ZipArchive',
				'required' => false,
			),
			'filter'    => array(
				'function' => 'filter_list',
				'required' => false,
			),
			'gd'        => array(
				'extension'    => 'gd',
				'required'     => false,
				'fallback_for' => 'imagick',
			),
			'iconv'     => array(
				'function' => 'iconv',
				'required' => false,
			),
			'mcrypt'    => array(
				'extension'    => 'mcrypt',
				'required'     => false,
				'fallback_for' => 'libsodium',
			),
			'simplexml' => array(
				'extension'    => 'simplexml',
				'required'     => false,
				'fallback_for' => 'mod_xml',
			),
			'xmlreader' => array(
				'extension'    => 'xmlreader',
				'required'     => false,
				'fallback_for' => 'mod_xml',
			),
			'zlib'      => array(
				'extension'    => 'zlib',
				'required'     => false,
				'fallback_for' => 'zip',
			),
		);

		/**
		 * An array representing all the modules we wish to test for.
		 *
		 * @since 5.2.0
		 * @since 5.3.0 The `$constant` and `$class` parameters were added.
		 *
		 * @param array $modules {
		 *     An associative array of modules to test for.
		 *
		 *     @type array ...$0 {
		 *         An associative array of module properties used during testing.
		 *         One of either `$function` or `$extension` must be provided, or they will fail by default.
		 *
		 *         @type string $function     Optional. A function name to test for the existence of.
		 *         @type string $extension    Optional. An extension to check if is loaded in PHP.
		 *         @type string $constant     Optional. A constant name to check for to verify an extension exists.
		 *         @type string $class        Optional. A class name to check for to verify an extension exists.
		 *         @type bool   $required     Is this a required feature or not.
		 *         @type string $fallback_for Optional. The module this module replaces as a fallback.
		 *     }
		 * }
		 */
		$modules = apply_filters( 'site_status_test_php_modules', $modules );

		$failures = array();

		foreach ( $modules as $library => $module ) {
			$extension  = ( isset( $module['extension'] ) ? $module['extension'] : null );
			$function   = ( isset( $module['function'] ) ? $module['function'] : null );
			$constant   = ( isset( $module['constant'] ) ? $module['constant'] : null );
			$class_name = ( isset( $module['class'] ) ? $module['class'] : null );

			// If this module is a fallback for another function, check if that other function passed.
			if ( isset( $module['fallback_for'] ) ) {
				/*
				 * If that other function has a failure, mark this module as required for usual operations.
				 * If that other function hasn't failed, skip this test as it's only a fallback.
				 */
				if ( isset( $failures[ $module['fallback_for'] ] ) ) {
					$module['required'] = true;
				} else {
					continue;
				}
			}

			if ( ! $this->test_php_extension_availability( $extension, $function, $constant, $class_name ) && ( ! isset( $module['php_bundled_version'] ) || version_compare( PHP_VERSION, $module['php_bundled_version'], '<' ) ) ) {
				if ( $module['required'] ) {
					$result['status'] = 'critical';

					$class         = 'error';
					$screen_reader = __( 'Error' );
					$message       = sprintf(
						/* translators: %s: The module name. */
						__( 'The required module, %s, is not installed, or has been disabled.' ),
						$library
					);
				} else {
					$class         = 'warning';
					$screen_reader = __( 'Warning' );
					$message       = sprintf(
						/* translators: %s: The module name. */
						__( 'The optional module, %s, is not installed, or has been disabled.' ),
						$library
					);
				}

				if ( ! $module['required'] && 'good' === $result['status'] ) {
					$result['status'] = 'recommended';
				}

				$failures[ $library ] = "<span class='dashicons $class'><span class='screen-reader-text'>$screen_reader</span></span> $message";
			}
		}

		if ( ! empty( $failures ) ) {
			$output = '<ul>';

			foreach ( $failures as $failure ) {
				$output .= sprintf(
					'<li>%s</li>',
					$failure
				);
			}

			$output .= '</ul>';
		}

		if ( 'good' !== $result['status'] ) {
			if ( 'recommended' === $result['status'] ) {
				$result['label'] = __( 'One or more recommended modules are missing' );
			}
			if ( 'critical' === $result['status'] ) {
				$result['label'] = __( 'One or more required modules are missing' );
			}

			$result['description'] .= $output;
		}