Source

File: wp-admin/includes/class-wp-site-health.php

public static function get_tests() {
		$tests = array(
			'direct' => array(
				'wordpress_version'         => array(
					'label' => __( 'WordPress Version' ),
					'test'  => 'wordpress_version',
				),
				'plugin_version'            => array(
					'label' => __( 'Plugin Versions' ),
					'test'  => 'plugin_version',
				),
				'theme_version'             => array(
					'label' => __( 'Theme Versions' ),
					'test'  => 'theme_version',
				),
				'php_version'               => array(
					'label' => __( 'PHP Version' ),
					'test'  => 'php_version',
				),
				'php_extensions'            => array(
					'label' => __( 'PHP Extensions' ),
					'test'  => 'php_extensions',
				),
				'php_default_timezone'      => array(
					'label' => __( 'PHP Default Timezone' ),
					'test'  => 'php_default_timezone',
				),
				'php_sessions'              => array(
					'label' => __( 'PHP Sessions' ),
					'test'  => 'php_sessions',
				),
				'sql_server'                => array(
					'label' => __( 'Database Server version' ),
					'test'  => 'sql_server',
				),
				'utf8mb4_support'           => array(
					'label' => __( 'MySQL utf8mb4 support' ),
					'test'  => 'utf8mb4_support',
				),
				'https_status'              => array(
					'label' => __( 'HTTPS status' ),
					'test'  => 'https_status',
				),
				'ssl_support'               => array(
					'label' => __( 'Secure communication' ),
					'test'  => 'ssl_support',
				),
				'scheduled_events'          => array(
					'label' => __( 'Scheduled events' ),
					'test'  => 'scheduled_events',
				),
				'http_requests'             => array(
					'label' => __( 'HTTP Requests' ),
					'test'  => 'http_requests',
				),
				'debug_enabled'             => array(
					'label' => __( 'Debugging enabled' ),
					'test'  => 'is_in_debug_mode',
				),
				'file_uploads'              => array(
					'label' => __( 'File uploads' ),
					'test'  => 'file_uploads',
				),
				'plugin_theme_auto_updates' => array(
					'label' => __( 'Plugin and theme auto-updates' ),
					'test'  => 'plugin_theme_auto_updates',
				),
			),
			'async'  => array(
				'dotorg_communication' => array(
					'label' => __( 'Communication with WordPress.org' ),
					'test'  => 'dotorg_communication',
				),
				'background_updates'   => array(
					'label' => __( 'Background updates' ),
					'test'  => 'background_updates',
				),
				'loopback_requests'    => array(
					'label' => __( 'Loopback request' ),
					'test'  => 'loopback_requests',
				),
			),
		);

		// Conditionally include REST rules if the function for it exists.
		if ( function_exists( 'rest_url' ) ) {
			$tests['direct']['rest_availability'] = array(
				'label' => __( 'REST API availability' ),
				'test'  => 'rest_availability',
			);
		}

		/**
		 * Add or modify which site status tests are run on a site.
		 *
		 * The site health is determined by a set of tests based on best practices from
		 * both the WordPress Hosting Team, but also web standards in general.
		 *
		 * Some sites may not have the same requirements, for example the automatic update
		 * checks may be handled by a host, and are therefore disabled in core.
		 * Or maybe you want to introduce a new test, is caching enabled/disabled/stale for example.
		 *
		 * Tests may be added either as direct, or asynchronous ones. Any test that may require some time
		 * to complete should run asynchronously, to avoid extended loading periods within wp-admin.
		 *
		 * @since 5.2.0
		 *
		 * @param array $test_type {
		 *     An associative array, where the `$test_type` is either `direct` or
		 *     `async`, to declare if the test should run via Ajax calls after page load.
		 *
		 *     @type array $identifier {
		 *         `$identifier` should be a unique identifier for the test that should run.
		 *         Plugins and themes are encouraged to prefix test identifiers with their slug
		 *         to avoid any collisions between tests.
		 *
		 *         @type string $label A friendly label for your test to identify it by.
		 *         @type mixed  $test  A callable to perform a direct test, or a string Ajax action to be called
		 *                             to perform an async test.
		 *     }
		 * }
		 */
		$tests = apply_filters( 'site_status_tests', $tests );

		// Ensure that the filtered tests contain the required array keys.
		$tests = array_merge(
			array(
				'direct' => array(),
				'async'  => array(),
			),
			$tests
		);

		return $tests;
	}