Update to Drupal 8.1.1. For more information, see https://www.drupal.org/node/2718713

core/modules/help/tests/modules/help_page_test/help_page_test.module

@@ -19,6 +19,8 @@ function help_page_test_help($route_name, RouteMatchInterface $route_match) {
       return t('Read the <a href=":url">online documentation for the Help Page Test module</a>.', [':url' => 'http://www.example.com']);
     case 'help_page_test.has_help':
       return t('I have help!');
+    case 'help_page_test.test_array':
+      return ['#markup' => 'Help text from help_page_test_help module.'];
   }
 
   // Ensure that hook_help() can return an empty string and not cause the block

core/modules/help/tests/modules/help_page_test/help_page_test.routing.yml

@@ -11,3 +11,10 @@ help_page_test.no_help:
     _controller: '\Drupal\help_page_test\HelpPageTestController::noHelp'
   requirements:
     _access: 'TRUE'
+
+help_page_test.test_array:
+  path: '/help_page_test/test_array'
+  defaults:
+    _controller: '\Drupal\help_page_test\HelpPageTestController::testArray'
+  requirements:
+    _access: 'TRUE'

core/modules/help/tests/modules/help_page_test/src/HelpPageTestController.php

@@ -27,4 +27,14 @@ class HelpPageTestController {
     return ['#markup' => 'A route without help.'];
   }
 
+  /**
+   * Provides a route which has multiple array returns from hook_help().
+   *
+   * @return array
+   *   A render array.
+   */
+  public function testArray() {
+    return ['#markup' => 'A route which has multiple array returns from hook_help().'];
+  }
+
 }

core/modules/help/tests/modules/more_help_page_test/more_help_page_test.info.yml

@@ -0,0 +1,7 @@
+name: 'More Help Page Test'
+type: module
+description: 'Module to test the help page.'
+package: Testing
+version: VERSION
+core: 8.x
+hidden: true

core/modules/help/tests/modules/more_help_page_test/more_help_page_test.module

@@ -0,0 +1,20 @@
+<?php
+
+/**
+ * @file
+ * More Help Page Test module to test the help blocks.
+ */
+
+use \Drupal\Core\Routing\RouteMatchInterface;
+
+/**
+ * Implements hook_help().
+ */
+function more_help_page_test_help($route_name, RouteMatchInterface $route_match) {
+
+  switch ($route_name) {
+    // Return help for the same route as the help_page_test module.
+    case 'help_page_test.test_array':
+      return ['#markup' => 'Help text from more_help_page_test_help module.'];
+  }
+}