diff --git a/src/Entity/Index.php b/src/Entity/Index.php
index 8a07deb..88148a5 100644
--- a/src/Entity/Index.php
+++ b/src/Entity/Index.php
@@ -1514,6 +1514,17 @@ class Index extends ConfigEntityBase implements IndexInterface {
       }
     }
 
+    $processors = $this->getOption('processors', array());
+    foreach ($dependencies['module'] as $module) {
+      foreach ($this->getProcessors(FALSE) as $key => $processor) {
+        if ($processor->getPluginDefinition()['provider'] == $module) {
+          unset($processors[$key]);
+          $changed = TRUE;
+        }
+      }
+    }
+    $this->setOption('processors', $processors);
+
     return $changed;
   }
 
diff --git a/src/Entity/Server.php b/src/Entity/Server.php
index b04cd1a..d2c74f2 100644
--- a/src/Entity/Server.php
+++ b/src/Entity/Server.php
@@ -440,8 +440,8 @@ class Server extends ConfigEntityBase implements ServerInterface {
     parent::calculateDependencies();
 
     // Add the backend's dependencies.
-    if ($this->hasValidBackend() && ($backend = $this->getBackend())) {
-      $this->addDependencies($backend->calculateDependencies());
+    if ($this->hasValidBackend()) {
+      $this->calculatePluginDependencies($this->getBackend());
     }
 
     return $this->dependencies;
diff --git a/src/Plugin/ConfigurablePluginBase.php b/src/Plugin/ConfigurablePluginBase.php
index d3edd25..0ea2a32 100644
--- a/src/Plugin/ConfigurablePluginBase.php
+++ b/src/Plugin/ConfigurablePluginBase.php
@@ -100,8 +100,7 @@ abstract class ConfigurablePluginBase extends PluginBase implements Configurable
    * {@inheritdoc}
    */
   public function calculateDependencies() {
-    $this->addDependency('module', $this->getPluginDefinition()['provider']);
-    return $this->dependencies;
+    return array();
   }
 
 }
diff --git a/src/Tests/DependencyRemovalTest.php b/src/Tests/DependencyRemovalTest.php
new file mode 100644
index 0000000..f0f082d
--- /dev/null
+++ b/src/Tests/DependencyRemovalTest.php
@@ -0,0 +1,100 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\search_api\Tests\DependencyRemovalTest.
+ */
+
+namespace Drupal\search_api\Tests;
+
+/**
+ * Tests what happens when an index's dependencies are removed.
+ *
+ * @group search_api
+ */
+class DependencyRemovalTest extends WebTestBase {
+
+  /**
+   * The permissions of the admin user.
+   *
+   * @var string[]
+   */
+  protected $adminUserPermissions = array(
+    'administer search_api',
+    'administer content types',
+    'access administration pages',
+    'administer modules',
+  );
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $modules = array(
+    'node',
+    'search_api',
+    'search_api_test_backend',
+    'search_api_test_processor',
+  );
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setUp() {
+    parent::setUp();
+
+    // Login with a user that has sufficient permissions, including
+    // uninstalling modules.
+    $this->drupalLogin($this->adminUser);
+
+    // Create a server and index.
+    $this->getTestServer();
+    $this->getTestIndex();
+  }
+
+  /**
+   * Tests whether removing dependencies of an index works correctly.
+   *
+   * Single test method to avoid the overhead of Drupal installation for each of
+   * the test methods.
+   */
+  public function testDependencyRemoval() {
+    $this->checkProcessorRemoval();
+  }
+
+  /**
+   * Tests the reaction of an index when a processor's module is removed.
+   *
+   * When a module that provides a processor is uninstalled, it should not
+   * delete the indexes that processor is enabled on. This would cause a chain
+   * removal of facets and views as well. Instead, the processor should just be
+   * disabled and no longer be found on the processors tab.
+   */
+  protected function checkProcessorRemoval() {
+    // Enable the dummy processor on the index.
+    $this->drupalGet($this->getIndexPath('processors'));
+    $this->assertText($this->t('Dummy processor'));
+    $this->drupalPostForm(NULL, array('status[dummy_processor]' => 1), $this->t('Save'));
+    $this->assertResponse(200);
+    $this->assertText($this->t('The indexing workflow was successfully edited.'));
+
+    // Uninstall the module.
+    $this->drupalGet('admin/modules/uninstall');
+    $this->drupalPostForm(NULL, array('uninstall[search_api_test_processor]' => 1), $this->t('Uninstall'));
+    // Make sure the index is not deleted when uninstalling the module.
+    $this->assertNoText($this->t('The listed configuration will be deleted.'));
+    $this->assertText($this->t('The listed configuration will be updated.'));
+
+    $this->drupalPostForm(NULL, array(), $this->t('Uninstall'));
+    $this->assertText($this->t('The selected modules have been uninstalled.'));
+
+    // Make sure the index is still actually present.
+    $this->drupalGet('admin/config/search/search-api');
+    $this->assertText('WebTest Index');
+
+    // Make sure the processor is no longer found on the processors tab.
+    $this->drupalGet($this->getIndexPath('processors'));
+    $this->assertResponse(200);
+    $this->assertNoText('Dummy processor');
+  }
+
+}
diff --git a/src/Tests/HooksTest.php b/src/Tests/HooksTest.php
index bc66fff..9f7ff4f 100644
--- a/src/Tests/HooksTest.php
+++ b/src/Tests/HooksTest.php
@@ -20,13 +20,6 @@ class HooksTest extends WebTestBase {
   public static $modules = array('node', 'search_api', 'search_api_test_backend', 'search_api_test_views', 'search_api_test_hooks');
 
   /**
-   * The id of the index.
-   *
-   * @var string
-   */
-  protected $indexId;
-
-  /**
    * Tests various operations via the Search API's admin UI.
    */
   public function testHooks() {
@@ -41,8 +34,7 @@ class HooksTest extends WebTestBase {
 
     // Create an index and server to work with.
     $this->getTestServer();
-    $index = $this->getTestIndex();
-    $this->indexId = $index->id();
+    $this->getTestIndex();
 
     // hook_search_api_backend_info_alter was triggered.
     $this->drupalGet('admin/config/search/search-api/add-server');
@@ -89,21 +81,4 @@ class HooksTest extends WebTestBase {
     $this->assertText('Llama');
   }
 
-  /**
-   * Returns the system path for the test index.
-   *
-   * @param string|null $tab
-   *   (optional) If set, the path suffix for a specific index tab.
-   *
-   * @return string
-   *   A system path.
-   */
-  protected function getIndexPath($tab = NULL) {
-    $path = 'admin/config/search/search-api/index/' . $this->indexId;
-    if ($tab) {
-      $path .= "/$tab";
-    }
-    return $path;
-  }
-
 }
diff --git a/src/Tests/IntegrationTest.php b/src/Tests/IntegrationTest.php
index 4d71336..a03fbac 100644
--- a/src/Tests/IntegrationTest.php
+++ b/src/Tests/IntegrationTest.php
@@ -27,13 +27,6 @@ class IntegrationTest extends WebTestBase {
   protected $serverId;
 
   /**
-   * The ID of the search index used for this test.
-   *
-   * @var string
-   */
-  protected $indexId;
-
-  /**
    * A storage instance for indexes.
    *
    * @var \Drupal\Core\Entity\EntityStorageInterface
@@ -805,23 +798,6 @@ class IntegrationTest extends WebTestBase {
   }
 
   /**
-   * Returns the system path for the test index.
-   *
-   * @param string|null $tab
-   *   (optional) If set, the path suffix for a specific index tab.
-   *
-   * @return string
-   *   A system path.
-   */
-  protected function getIndexPath($tab = NULL) {
-    $path = 'admin/config/search/search-api/index/' . $this->indexId;
-    if ($tab) {
-      $path .= "/$tab";
-    }
-    return $path;
-  }
-
-  /**
    * Retrieves test index.
    *
    * @return \Drupal\search_api\IndexInterface
diff --git a/src/Tests/Processor/ProcessorIntegrationTest.php b/src/Tests/Processor/ProcessorIntegrationTest.php
index ac22441..25b4075 100644
--- a/src/Tests/Processor/ProcessorIntegrationTest.php
+++ b/src/Tests/Processor/ProcessorIntegrationTest.php
@@ -20,13 +20,6 @@ use Drupal\search_api\Tests\WebTestBase;
 class ProcessorIntegrationTest extends WebTestBase {
 
   /**
-   * The ID of the search index used by this test.
-   *
-   * @var string
-   */
-  protected $indexId;
-
-  /**
    * {@inheritdoc}
    */
   public function setUp() {
diff --git a/src/Tests/ViewsTest.php b/src/Tests/ViewsTest.php
index e84e258..d8976d8 100644
--- a/src/Tests/ViewsTest.php
+++ b/src/Tests/ViewsTest.php
@@ -26,13 +26,6 @@ class ViewsTest extends WebTestBase {
   public static $modules = array('search_api_test_views');
 
   /**
-   * A search index ID.
-   *
-   * @var string
-   */
-  protected $indexId = 'database_search_index';
-
-  /**
    * {@inheritdoc}
    */
   public function setUp() {
@@ -40,6 +33,7 @@ class ViewsTest extends WebTestBase {
 
     $this->setUpExampleStructure();
 
+    $this->indexId = 'database_search_index';
     \Drupal::getContainer()->get('search_api.index_task_manager')->addItemsAll(Index::load($this->indexId));
   }
 
diff --git a/src/Tests/WebTestBase.php b/src/Tests/WebTestBase.php
index f19efd0..a2d7734 100644
--- a/src/Tests/WebTestBase.php
+++ b/src/Tests/WebTestBase.php
@@ -32,6 +32,15 @@ abstract class WebTestBase extends SimpletestWebTestBase {
    * @var \Drupal\Core\Session\AccountInterface
    */
   protected $adminUser;
+  /**
+   * The permissions of the admin user.
+   *
+   * @var string[]
+  */
+  protected $adminUserPermissions = array(
+    'administer search_api',
+    'access administration pages'
+  );
 
   /**
    * A user without Search API admin permission.
@@ -55,13 +64,20 @@ abstract class WebTestBase extends SimpletestWebTestBase {
   protected $urlGenerator;
 
   /**
+   * The ID of the search index used for this test.
+   *
+   * @var string
+   */
+  protected $indexId;
+
+  /**
    * {@inheritdoc}
    */
   public function setUp() {
     parent::setUp();
 
     // Create the users used for the tests.
-    $this->adminUser = $this->drupalCreateUser(array('administer search_api', 'access administration pages'));
+    $this->adminUser = $this->drupalCreateUser($this->adminUserPermissions);
     $this->unauthorizedUser = $this->drupalCreateUser(array('access administration pages'));
     $this->anonymousUser = $this->drupalCreateUser();
 
@@ -101,6 +117,7 @@ abstract class WebTestBase extends SimpletestWebTestBase {
    */
   public function getTestServer($name = 'WebTest server', $id = 'webtest_server', $backend_id = 'search_api_test_backend', $backend_config = array(), $reset = FALSE) {
     if ($reset) {
+      /** @var \Drupal\search_api\ServerInterface $server */
       $server = Server::load($id);
       if ($server) {
         $server->delete();
@@ -140,6 +157,7 @@ abstract class WebTestBase extends SimpletestWebTestBase {
    */
   public function getTestIndex($name = 'WebTest Index', $id = 'webtest_index', $server_id = 'webtest_server', $datasource_id = 'entity:node', $reset = FALSE) {
     if ($reset) {
+      /** @var \Drupal\search_api\IndexInterface $index */
       $index = Index::load($id);
       if ($index) {
         $index->delete();
@@ -154,9 +172,27 @@ abstract class WebTestBase extends SimpletestWebTestBase {
         'datasources' => array($datasource_id),
       ));
       $index->save();
+      $this->indexId = $index->id();
     }
 
     return $index;
   }
 
+  /**
+   * Returns the system path for the test index.
+   *
+   * @param string|null $tab
+   *   (optional) If set, the path suffix for a specific index tab.
+   *
+   * @return string
+   *   A system path.
+   */
+  protected function getIndexPath($tab = NULL) {
+    $path = 'admin/config/search/search-api/index/' . $this->indexId;
+    if ($tab) {
+      $path .= "/$tab";
+    }
+    return $path;
+  }
+
 }
diff --git a/tests/search_api_test_processor/config/schema/search_api_test_processor.schema.yml b/tests/search_api_test_processor/config/schema/search_api_test_processor.schema.yml
new file mode 100644
index 0000000..a9c5c2c
--- /dev/null
+++ b/tests/search_api_test_processor/config/schema/search_api_test_processor.schema.yml
@@ -0,0 +1,10 @@
+plugin.plugin_configuration.search_api_processor.dummy_processor:
+  type: mapping
+  label: 'Dummy processor configuration'
+  mapping:
+    fields:
+      type: sequence
+      label: 'The selected fields'
+      sequence:
+        type: string
+        label: 'Selected field'
diff --git a/tests/search_api_test_processor/search_api_test_processor.info.yml b/tests/search_api_test_processor/search_api_test_processor.info.yml
new file mode 100644
index 0000000..de85f76
--- /dev/null
+++ b/tests/search_api_test_processor/search_api_test_processor.info.yml
@@ -0,0 +1,8 @@
+name: 'Search API Custom processor Test'
+type: module
+description: 'Support module for Search API tests'
+package: Search
+dependencies:
+  - search_api:search_api
+core: 8.x
+hidden: true
diff --git a/tests/search_api_test_processor/src/Plugin/search_api/processor/DummyProcessor.php b/tests/search_api_test_processor/src/Plugin/search_api/processor/DummyProcessor.php
new file mode 100644
index 0000000..537e6c7
--- /dev/null
+++ b/tests/search_api_test_processor/src/Plugin/search_api/processor/DummyProcessor.php
@@ -0,0 +1,35 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\search_api_test_processor\Plugin\search_api\processor\DummyProcessor.
+ */
+
+namespace Drupal\search_api_test_processor\Plugin\search_api\processor;
+
+use Drupal\search_api\Processor\FieldsProcessorPluginBase;
+
+/**
+ * @SearchApiProcessor(
+ *   id = "dummy_processor",
+ *   label = @Translation("Dummy processor"),
+ *   description = @Translation("Makes dummy operations."),
+ *   stages = {
+ *     "preprocess_index" = -20,
+ *     "preprocess_query" = -20
+ *   }
+ * )
+ */
+class DummyProcessor extends FieldsProcessorPluginBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function process(&$value) {
+    // We don't touch integers, NULL values or the like.
+    if (is_string($value)) {
+      $value .= ' dummy processor touched this';
+    }
+  }
+
+}