diff --git a/src/Backend/BackendPluginManager.php b/src/Backend/BackendPluginManager.php
index c498cc4..d1cdab2 100644
--- a/src/Backend/BackendPluginManager.php
+++ b/src/Backend/BackendPluginManager.php
@@ -5,6 +5,8 @@ namespace Drupal\search_api\Backend;
 use Drupal\Core\Cache\CacheBackendInterface;
 use Drupal\Core\Extension\ModuleHandlerInterface;
 use Drupal\Core\Plugin\DefaultPluginManager;
+use Drupal\search_api\Event\BackendInfo;
+use Drupal\search_api\Annotation\SearchApiBackend;
 
 /**
  * Manages search backend plugins.
@@ -28,9 +30,18 @@ class BackendPluginManager extends DefaultPluginManager {
    *   The module handler.
    */
   public function __construct(\Traversable $namespaces, CacheBackendInterface $cache_backend, ModuleHandlerInterface $module_handler) {
-    parent::__construct('Plugin/search_api/backend', $namespaces, $module_handler, 'Drupal\search_api\Backend\BackendInterface', 'Drupal\search_api\Annotation\SearchApiBackend');
+    parent::__construct('Plugin/search_api/backend', $namespaces, $module_handler, BackendInterface::class, SearchApiBackend::class);
     $this->setCacheBackend($cache_backend, 'search_api_backends');
-    $this->alterInfo('search_api_backend_info');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function alterDefinitions(&$definitions) {
+     $this->moduleHandler->alterDeprecated('Use the BackendInfo event instead.', 'search_api_backend_info', $definitions);
+     /** @var \Symfony\Component\EventDispatcher\EventDispatcherInterface $dispatcher */
+     $dispatcher = \Drupal::getContainer()->get('event_dispatcher');
+     $dispatcher->dispatch(BackendInfo::NAME, new BackendInfo($definitions));
   }
 
 }
diff --git a/src/Datasource/DatasourcePluginManager.php b/src/Datasource/DatasourcePluginManager.php
index be9e684..a4b1a50 100644
--- a/src/Datasource/DatasourcePluginManager.php
+++ b/src/Datasource/DatasourcePluginManager.php
@@ -5,6 +5,7 @@ namespace Drupal\search_api\Datasource;
 use Drupal\Core\Cache\CacheBackendInterface;
 use Drupal\Core\Extension\ModuleHandlerInterface;
 use Drupal\Core\Plugin\DefaultPluginManager;
+use Drupal\search_api\Event\DatasourceInfo;
 
 /**
  * Manages datasource plugins.
@@ -30,7 +31,16 @@ class DatasourcePluginManager extends DefaultPluginManager {
   public function __construct(\Traversable $namespaces, CacheBackendInterface $cache_backend, ModuleHandlerInterface $module_handler) {
     parent::__construct('Plugin/search_api/datasource', $namespaces, $module_handler, 'Drupal\search_api\Datasource\DatasourceInterface', 'Drupal\search_api\Annotation\SearchApiDatasource');
     $this->setCacheBackend($cache_backend, 'search_api_datasources');
-    $this->alterInfo('search_api_datasource_info');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function alterDefinitions(&$definitions) {
+    $this->moduleHandler->alterDeprecated('Use the DatasourceInfo event instead.', 'search_api_datasource_info', $definitions);
+    /** @var \Symfony\Component\EventDispatcher\EventDispatcherInterface $dispatcher */
+    $dispatcher = \Drupal::getContainer()->get('event_dispatcher');
+    $dispatcher->dispatch(DatasourceInfo::NAME, new DatasourceInfo($definitions));
   }
 
 }
diff --git a/src/Entity/Index.php b/src/Entity/Index.php
index 7765e07..fb3f186 100644
--- a/src/Entity/Index.php
+++ b/src/Entity/Index.php
@@ -8,6 +8,8 @@ use Drupal\Core\Cache\Cache;
 use Drupal\Core\Config\Entity\ConfigEntityBase;
 use Drupal\Core\Entity\EntityStorageInterface;
 use Drupal\search_api\Datasource\DatasourceInterface;
+use Drupal\search_api\Event\ItemsIndexed;
+use Drupal\search_api\Event\Reindex;
 use Drupal\search_api\IndexInterface;
 use Drupal\search_api\Item\FieldInterface;
 use Drupal\search_api\LoggerTrait;
@@ -20,6 +22,7 @@ use Drupal\search_api\Tracker\TrackerInterface;
 use Drupal\search_api\Utility\Utility;
 use Drupal\Core\TempStore\TempStoreException;
 use Drupal\views\Views;
+use Symfony\Component\EventDispatcher\Event;
 
 /**
  * Defines the search index configuration entity.
@@ -996,7 +999,13 @@ class Index extends ConfigEntityBase implements IndexInterface {
       // Since we've indexed items now, triggering reindexing would have some
       // effect again. Therefore, we reset the flag.
       $this->setHasReindexed(FALSE);
-      \Drupal::moduleHandler()->invokeAll('search_api_items_indexed', [$this, $processed_ids]);
+
+      $warning = 'Use the ItemsIndexed event instead';
+      \Drupal::moduleHandler()->invokeAllDeprecated($warning, 'search_api_items_indexed', [$this, $processed_ids]);
+
+      /** @var \Symfony\Component\EventDispatcher\EventDispatcherInterface $dispatcher */
+      $dispatcher = \Drupal::getContainer()->get('event_dispatcher');
+      $dispatcher->dispatch(ItemsIndexed::NAME, new ItemsIndexed($this, $processed_ids));
 
       // Clear search api list caches.
       Cache::invalidateTags(['search_api_list:' . $this->id]);
@@ -1100,7 +1109,10 @@ class Index extends ConfigEntityBase implements IndexInterface {
     if ($this->status() && !$this->isReindexing()) {
       $this->setHasReindexed();
       $this->getTrackerInstance()->trackAllItemsUpdated();
-      \Drupal::moduleHandler()->invokeAll('search_api_index_reindex', [$this, FALSE]);
+      \Drupal::moduleHandler()->invokeAllDeprecated('Use the Reindex event instead.','search_api_index_reindex', [$this, FALSE]);
+      /** @var \Symfony\Component\EventDispatcher\EventDispatcherInterface $dispatcher */
+      $dispatcher = \Drupal::getContainer()->get('event_dispatcher');
+      $dispatcher->dispatch(Reindex::NAME, new Reindex($this, FALSE));
     }
   }
 
@@ -1125,7 +1137,11 @@ class Index extends ConfigEntityBase implements IndexInterface {
     }
     if ($invoke_hook) {
       \Drupal::moduleHandler()
-        ->invokeAll('search_api_index_reindex', [$this, !$this->isReadOnly()]);
+        ->invokeAllDeprecated('Use the Reindex event instead.', 'search_api_index_reindex', [$this, !$this->isReadOnly()]);
+
+      /** @var \Symfony\Component\EventDispatcher\EventDispatcherInterface $dispatcher */
+      $dispatcher = \Drupal::getContainer()->get('event_dispatcher');
+      $dispatcher->dispatch(Reindex::NAME, new Reindex($this, !$this->isReadOnly()));
     }
   }
 
@@ -1143,7 +1159,10 @@ class Index extends ConfigEntityBase implements IndexInterface {
     $index_task_manager->startTracking($this);
     $this->setHasReindexed();
     \Drupal::moduleHandler()
-      ->invokeAll('search_api_index_reindex', [$this, FALSE]);
+      ->invokeAllDeprecated('Use the Reindex event instead.', 'search_api_index_reindex', [$this, FALSE]);
+    /** @var \Symfony\Component\EventDispatcher\EventDispatcherInterface $dispatcher */
+    $dispatcher = \Drupal::getContainer()->get('event_dispatcher');
+    $dispatcher->dispatch(Reindex::NAME, new Reindex($this, FALSE));
     $index_task_manager->addItemsBatch($this);
   }
 
diff --git a/src/Event/BackendInfo.php b/src/Event/BackendInfo.php
new file mode 100644
index 0000000..800d0cf
--- /dev/null
+++ b/src/Event/BackendInfo.php
@@ -0,0 +1,41 @@
+<?php
+
+namespace Drupal\search_api\Event;
+
+use Symfony\Component\EventDispatcher\Event;
+
+/**
+ * Implementation of the backend info event.
+ */
+class BackendInfo extends Event {
+
+  const NAME = 'search_api.backend_info';
+
+  /**
+   * The Search API backend info array, keyed by backend ID.
+   *
+   * @var array
+   */
+  private $backendInfo;
+
+  /**
+   * Constructor for the BackendInfo event.
+   *
+   * @param array $backendInfo
+   *   The Search API backend info array, keyed by backend ID.
+   */
+  public function __construct(array &$backendInfo) {
+    $this->backendInfo = &$backendInfo;
+  }
+
+  /**
+   * Gets the Search API backend info array.
+   *
+   * @return array
+   *   Reference to the Search API backend info array, keyed by backend ID.
+   */
+  public function &getBackendInfo() {
+    return $this->backendInfo;
+  }
+
+}
diff --git a/src/Event/DatasourceInfo.php b/src/Event/DatasourceInfo.php
new file mode 100644
index 0000000..889200c
--- /dev/null
+++ b/src/Event/DatasourceInfo.php
@@ -0,0 +1,39 @@
+<?php
+
+namespace Drupal\search_api\Event;
+
+use Symfony\Component\EventDispatcher\Event;
+
+/**
+ * Implementation of the datasource info event.
+ */
+class DatasourceInfo extends Event {
+
+  const NAME = 'search_api.datasource_info';
+
+  /**
+   * Reference to the datasource infos.
+   * @var
+   */
+  private $infos;
+
+  /**
+   * Constructor of the DatasourceInfo event.
+   *
+   * @param array $infos
+   *   A reference to the datasource infos.
+   */
+  public function __construct(array &$infos) {
+    $this->infos = &$infos;
+  }
+
+  /**
+   * Get a reference to the datasource infos.
+   *
+   * @return mixed
+   */
+  public function &getInfos() {
+    return $this->infos;
+  }
+
+}
\ No newline at end of file
diff --git a/src/Event/ItemsIndexed.php b/src/Event/ItemsIndexed.php
new file mode 100644
index 0000000..3eca00c
--- /dev/null
+++ b/src/Event/ItemsIndexed.php
@@ -0,0 +1,60 @@
+<?php
+
+namespace Drupal\search_api\Event;
+
+use Drupal\search_api\IndexInterface;
+use Symfony\Component\EventDispatcher\Event;
+
+/**
+ * Implementation of the items indexed event.
+ */
+class ItemsIndexed extends Event {
+
+  const NAME = 'search_api.items_indexed';
+
+  /**
+   * The index that indexed the items.
+   *
+   * @var \Drupal\search_api\IndexInterface
+   */
+  private $index;
+
+  /**
+   * The processed ids.
+   *
+   * @var array
+   */
+  private $processedIds;
+
+  /**
+   * Constructor for the ItemsIndexed event.
+   *
+   * @param \Drupal\search_api\IndexInterface $index
+   *   The index that indexed the items.
+   * @param int[] $processedIds
+   *   The processed ids.
+   */
+  public function __construct(IndexInterface $index, array $processedIds) {
+    $this->index = $index;
+    $this->processedIds = $processedIds;
+  }
+
+  /**
+   * Get the index that indexed the items.
+   *
+   * @return \Drupal\search_api\IndexInterface
+   */
+  public function getIndex() {
+    return $this->index;
+  }
+
+  /**
+   * Get the processed ids.
+   *
+   * @return int[]
+   */
+  public function getProcessedIds() {
+    return $this->processedIds;
+  }
+
+}
diff --git a/src/Event/Reindex.php b/src/Event/Reindex.php
new file mode 100644
index 0000000..3289951
--- /dev/null
+++ b/src/Event/Reindex.php
@@ -0,0 +1,60 @@
+<?php
+
+namespace Drupal\search_api\Event;
+
+use Drupal\search_api\IndexInterface;
+use Symfony\Component\EventDispatcher\Event;
+
+/**
+ * Implementation of the reindex index event.
+ */
+class Reindex extends Event {
+
+  const NAME = 'search_api.reindex';
+
+  /**
+   * The index scheduled for reindexing.
+   *
+   * @var \Drupal\search_api\IndexInterface
+   */
+  private $index;
+
+  /**
+   * Boolean indicating whether the index was also cleared.
+   *
+   * @var bool
+   */
+  private $clear;
+
+  /**
+   * Constructor for the reindex event.
+   *
+   * @param \Drupal\search_api\IndexInterface $index
+   *   The index scheduled for reindexing.
+   * @param bool $clear
+   *   Boolean indicating whether the index was also cleared.
+   */
+  public function __construct(IndexInterface $index, $clear) {
+    $this->index = $index;
+    $this->clear = $clear;
+  }
+
+  /**
+   * Get the index scheduled for reindexing.
+   *
+   * @return \Drupal\search_api\IndexInterface
+   */
+  public function getIndex() {
+    return $this->index;
+  }
+
+  /**
+   * Get the boolean indicating whether the index was also cleared.
+   *
+   * @return bool
+   */
+  public function isClear() {
+    return $this->clear;
+  }
+
+}
\ No newline at end of file
diff --git a/src/Utility/CommandHelper.php b/src/Utility/CommandHelper.php
index 86b68f1..e53818b 100644
--- a/src/Utility/CommandHelper.php
+++ b/src/Utility/CommandHelper.php
@@ -8,6 +8,7 @@ use Drupal\Core\Entity\EntityStorageException;
 use Drupal\Core\Entity\EntityTypeManagerInterface;
 use Drupal\Core\Extension\ModuleHandlerInterface;
 use Drupal\search_api\ConsoleException;
+use Drupal\search_api\Event\Reindex;
 use Drupal\search_api\IndexBatchHelper;
 use Drupal\search_api\IndexInterface;
 use Drupal\search_api\SearchApiException;
@@ -354,7 +355,10 @@ class CommandHelper implements LoggerAwareInterface {
             $reindexed_datasources[] = $datasource->label();
           }
         }
-        $this->moduleHandler->invokeAll('search_api_index_reindex', [$index, FALSE]);
+        $this->moduleHandler->invokeAllDeprecated('Use the Reindex event instead.', 'search_api_index_reindex', [$index, FALSE]);
+        /** @var \Symfony\Component\EventDispatcher\EventDispatcherInterface $dispatcher */
+        $dispatcher = \Drupal::getContainer()->get('event_dispatcher');
+        $dispatcher->dispatch(Reindex::NAME, new Reindex($index, FALSE));
         $arguments = [
           '!index' => $index->label(),
           '!datasources' => implode(', ', $reindexed_datasources),
diff --git a/tests/search_api_test_events/search_api_test_events.info.yml b/tests/search_api_test_events/search_api_test_events.info.yml
new file mode 100644
index 0000000..2bf1bcc
--- /dev/null
+++ b/tests/search_api_test_events/search_api_test_events.info.yml
@@ -0,0 +1,8 @@
+name: 'Search API Events Test'
+type: module
+description: 'Support module for Search API tests, tests all the events.'
+package: Testing
+dependencies:
+  - search_api:search_api
+core: 8.x
+hidden: true
diff --git a/tests/search_api_test_events/search_api_test_events.services.yml b/tests/search_api_test_events/search_api_test_events.services.yml
new file mode 100644
index 0000000..9ac7d9b
--- /dev/null
+++ b/tests/search_api_test_events/search_api_test_events.services.yml
@@ -0,0 +1,7 @@
+services:
+
+  search_api_test_events.event_listener:
+    class: \Drupal\search_api_test_events\EventListener
+    arguments: ['@messenger']
+    tags:
+      - { name: event_subscriber }
diff --git a/tests/search_api_test_events/src/EventListener.php b/tests/search_api_test_events/src/EventListener.php
new file mode 100644
index 0000000..2ef0311
--- /dev/null
+++ b/tests/search_api_test_events/src/EventListener.php
@@ -0,0 +1,92 @@
+<?php
+
+namespace Drupal\search_api_test_events;
+
+use Drupal\Core\Messenger\MessengerInterface;
+use Drupal\search_api\Event\BackendInfo;
+use Drupal\search_api\Event\DatasourceInfo;
+use Drupal\search_api\Event\ItemsIndexed;
+use Drupal\search_api\Event\Reindex;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+
+/**
+ * Class EventListener
+ *
+ * @package Drupal\search_api_test_events
+ */
+class EventListener implements EventSubscriberInterface {
+
+  /**
+   * The messenger.
+   *
+   * @var \Drupal\Core\Messenger\MessengerInterface
+   */
+  private $messenger;
+
+  /**
+   * EventListener constructor.
+   *
+   * @param \Drupal\Core\Messenger\MessengerInterface $messenger
+   *   The messenger.
+   */
+  public function __construct(MessengerInterface $messenger) {
+    $this->messenger = $messenger;
+  }
+
+  /**
+   * {@inheritDoc}
+   */
+  public static function getSubscribedEvents() {
+    return [
+      BackendInfo::NAME => 'backendInfo',
+      DatasourceInfo::NAME => 'datasourceInfo',
+      ItemsIndexed::NAME => 'itemsIndexed',
+      Reindex::NAME => 'reindex',
+    ];
+  }
+
+  /**
+   * Event handler for the backend info event.
+   *
+   * @param \Drupal\search_api\Event\BackendInfo $event
+   *   The backend info event.
+   */
+  public function backendInfo(BackendInfo $event) {
+    $backend_info = &$event->getBackendInfo();
+    $backend_info['search_api_test']['label'] = 'Slims return';
+  }
+
+  /**
+   * Event handler for the datasource info event.
+   *
+   * @param \Drupal\search_api\Event\DatasourceInfo $event
+   *   The datasource info event.
+   */
+  public function datasourceInfo(DatasourceInfo $event) {
+    $infos = &$event->getInfos();
+    if (isset($infos['entity:node'])) {
+      $infos['entity:node']['label'] = 'Distant land';
+    }
+  }
+
+  /**
+   * Event handler for the items indexed event.
+   *
+   * @param \Drupal\search_api\Event\ItemsIndexed $event
+   *   The items indexed event.
+   */
+  public function itemsIndexed(ItemsIndexed $event) {
+    $this->messenger->addStatus('Please set me at ease');
+  }
+
+  /**
+   * Event handler for the reindex event.
+   *
+   * @param \Drupal\search_api\Event\Reindex $event
+   *   The reindex index event.
+   */
+  public function reindex(Reindex $event) {
+    $this->messenger->addStatus('Montara');
+  }
+
+}
diff --git a/tests/src/Functional/EventsTest.php b/tests/src/Functional/EventsTest.php
new file mode 100644
index 0000000..52356ba
--- /dev/null
+++ b/tests/src/Functional/EventsTest.php
@@ -0,0 +1,165 @@
+<?php
+
+namespace Drupal\Tests\search_api\Functional;
+
+use Drupal\search_api\Entity\Index;
+use Drupal\search_api_test\PluginTestTrait;
+
+/**
+ * Tests integration of events.
+ *
+ * @group search_api
+ */
+class EventsTest extends SearchApiBrowserTestBase {
+
+  use PluginTestTrait;
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $modules = [
+    'node',
+    'rest',
+    'search_api',
+    'search_api_test',
+    'search_api_test_views',
+    'search_api_test_events',
+  ];
+
+  /**
+   * The test server.
+   *
+   * @var \Drupal\search_api\ServerInterface
+   */
+  protected $server;
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setUp() {
+    parent::setUp();
+
+    // Create some nodes.
+    $this->drupalCreateNode(['type' => 'page', 'title' => 'node - 1']);
+    $this->drupalCreateNode(['type' => 'page', 'title' => 'node - 2']);
+    $this->drupalCreateNode(['type' => 'page', 'title' => 'node - 3']);
+    $this->drupalCreateNode(['type' => 'page', 'title' => 'node - 4']);
+
+    // Create an index and server to work with.
+    $this->server = $this->getTestServer();
+    $index = $this->getTestIndex();
+
+    // Add the test processor to the index so we can make sure that all expected
+    // processor methods are called, too.
+    /** @var \Drupal\search_api\Processor\ProcessorInterface $processor */
+    $processor = \Drupal::getContainer()
+      ->get('search_api.plugin_helper')
+      ->createProcessorPlugin($index, 'search_api_test');
+    $index->addProcessor($processor)->save();
+
+    // Parts of this test actually use the "database_search_index" from the
+    // search_api_test_db module (via the test view). Set the processor there,
+    // too.
+    $index = Index::load('database_search_index');
+    $processor = \Drupal::getContainer()
+      ->get('search_api.plugin_helper')
+      ->createProcessorPlugin($index, 'search_api_test');
+    $index->addProcessor($processor)->save();
+
+    // Reset the called methods on the processor.
+    $this->getCalledMethods('processor');
+
+    // Log in, so we can test all the things.
+    $this->drupalLogin($this->adminUser);
+  }
+
+  /**
+   * Tests various operations via the Search API's admin UI.
+   */
+  public function testEvents() {
+    // The BackendInfo event was invoked.
+    $this->drupalGet('admin/config/search/search-api/add-server');
+    $this->assertSession()->pageTextContains('Slims return');
+
+    // The DatasourceInfo event was invoked.
+    $this->drupalGet('admin/config/search/search-api/add-index');
+    $this->assertSession()->pageTextContains('Distant land');
+    // hook_search_api_tracker_info_alter() was invoked.
+//    $this->assertSession()->pageTextContains('Good luck');
+
+    // hook_search_api_processor_info_alter() was invoked.
+    $this->drupalGet($this->getIndexPath('processors'));
+//    $this->assertSession()->pageTextContains('Mystic bounce');
+
+    // hook_search_api_parse_mode_info_alter was invoked.
+    $definition = \Drupal::getContainer()
+      ->get('plugin.manager.search_api.parse_mode')
+      ->getDefinition('direct');
+//    $this->assertEquals('Song for My Father', $definition['label']);
+
+    // Saving the index should trigger the processor's preIndexSave() method.
+    $this->submitForm([], 'Save');
+    $processor_methods = $this->getCalledMethods('processor');
+    $this->assertEquals(['preIndexSave'], $processor_methods);
+
+    $this->drupalGet($this->getIndexPath());
+    // Duplication on value 'Index now' with summary.
+    $this->submitForm([], 'Index now');
+    $this->checkForMetaRefresh();
+    $this->assertSession()->pageTextContains('Successfully indexed 4 items.');
+
+    // During indexing, alterIndexedItems() and preprocessIndexItems() should be
+    // called on the processor.
+    $processor_methods = $this->getCalledMethods('processor');
+    $expected = ['alterIndexedItems', 'preprocessIndexItems'];
+    $this->assertEquals($expected, $processor_methods);
+
+    // hook_search_api_index_items_alter() was invoked, this removed node:1.
+    // hook_search_api_query_TAG_alter() was invoked, this removed node:3.
+//    $this->assertSession()->pageTextContains('There are 2 items indexed on the server for this index.');
+//    $this->assertSession()->pageTextContains('Stormy');
+
+    // The ItemsIndexed event was invoked.
+    $this->assertSession()->pageTextContains('Please set me at ease');
+
+    // The Reindex event was invoked.
+    $this->drupalGet($this->getIndexPath('reindex'));
+    $this->submitForm([], 'Confirm');
+    $this->assertSession()->pageTextContains('Montara');
+
+    return; // @todo implement other events
+    // hook_search_api_data_type_info_alter() was invoked.
+    $this->drupalGet($this->getIndexPath('fields'));
+    $this->assertSession()->pageTextContains('Peace/Dolphin dance');
+    // The implementation of hook_search_api_field_type_mapping_alter() has
+    // removed all dates, so we can't see any timestamp anymore in the page.
+    $url_options['query']['datasource'] = 'entity:node';
+    $this->drupalGet($this->getIndexPath('fields/add/nojs'), $url_options);
+    $this->assertSession()->pageTextContains('Add fields to index');
+    $this->assertSession()->pageTextNotContains('timestamp');
+
+    $this->drupalGet('search-api-test');
+    $this->assertSession()->pageTextContains('Search id: views_page:search_api_test_view__page_1');
+    // hook_search_api_query_alter() was invoked.
+    $this->assertSession()->pageTextContains('Funky blue note');
+    // hook_search_api_results_alter() was invoked.
+    $this->assertSession()->pageTextContains('Stepping into tomorrow');
+    // hook_search_api_results_TAG_alter() was invoked.
+    $this->assertSession()->pageTextContains('Llama');
+
+    // The query alter methods of the processor were called.
+    $processor_methods = $this->getCalledMethods('processor');
+    $expected = ['preprocessSearchQuery', 'postprocessSearchResults'];
+    $this->assertEquals($expected, $processor_methods);
+
+    // hook_search_api_server_features_alter() is triggered.
+    $this->assertTrue($this->server->supportsFeature('welcome_to_the_jungle'));
+
+    $displays = \Drupal::getContainer()->get('plugin.manager.search_api.display')
+      ->getInstances();
+    // hook_search_api_displays_alter was invoked.
+    $display_label = $displays['views_page:search_api_test_view__page_1']->label();
+    $this->assertEquals('Some funny label for testing', $display_label);
+  }
+
+}