Add Elasticsearch health check

elasticpress.php

@@ -75,6 +75,7 @@ function( $class ) {
 
 require_once __DIR__ . '/includes/compat.php';
 require_once __DIR__ . '/includes/utils.php';
+require_once __DIR__ . '/includes/health-check.php';
 
 // Define a constant if we're network activated to allow plugin to respond accordingly.
 $network_activated = Utils\is_network_activated( EP_FILE );

includes/health-check.php

@@ -0,0 +1,21 @@
+<?php
+/**
+ * Health check
+ *
+ * @package elasticpress
+ * @since   3.6.0
+ */
+
+namespace ElasticPress;
+
+if ( ! defined( 'ABSPATH' ) ) {
+	exit; // Exit if accessed directly.
+}
+
+$health_checks = [
+	new HealthCheck\HealthCheckElasticsearch(),
+];
+
+foreach ( $health_checks as $health_check ) {
+	$health_check->register_test();
+}