diff --git a/tests/src/Unit/Plugin/Processor/AddHierarchyTest.php b/tests/src/Unit/Plugin/Processor/AddHierarchyTest.php
deleted file mode 100644
index e3be2a3..0000000
--- a/tests/src/Unit/Plugin/Processor/AddHierarchyTest.php
+++ /dev/null
@@ -1,105 +0,0 @@
-<?php
-
-namespace Drupal\Tests\search_api\Unit\Plugin\Processor;
-
-use Drupal\Core\TypedData\DataDefinition;
-use Drupal\search_api\Datasource\DatasourceInterface;
-use Drupal\search_api\IndexInterface;
-use Drupal\search_api\Item\FieldInterface;
-use Drupal\search_api\Plugin\search_api\processor\AddHierarchy;
-use Drupal\Tests\UnitTestCase;
-use Prophecy\Argument;
-
-/**
- * Tests for the "Hierarchy" plugin.
- *
- * @group search_api
- *
- * @coversDefaultClass \Drupal\search_api\Plugin\search_api\processor\AddHierarchy
- */
-class AddHierarchyTest extends UnitTestCase {
-
-  /**
-   * The processor to be tested.
-   *
-   * @var \Drupal\search_api\Plugin\search_api\processor\AddHierarchy
-   */
-  protected $processor;
-
-  /**
-   * The string translaton service to use.
-   *
-   * @var \Drupal\Core\StringTranslation\TranslationInterface
-   */
-  protected $translation;
-
-  /**
-   * {@inheritdoc}
-   */
-  public function setUp() {
-    parent::setUp();
-
-    // Test without term storage.
-    $this->processor = new AddHierarchy(array(), 'hierarchy', array());
-    $this->translation = $this->getStringTranslationStub();
-    $this->processor->setStringTranslation($this->translation);
-  }
-
-  /**
-   * Test data properties alter.
-   *
-   * @covers ::alterPropertyDefinitions
-   * @covers ::isEntityReferenceField
-   */
-  public function testAlterPropertyDefinitions() {
-    // Without a datasource, properties should be unaltered.
-    $expected = $properties = array(
-      'foo' => 'bar',
-    );
-    $this->processor->alterPropertyDefinitions($properties);
-    $this->assertArrayEquals($expected, $properties);
-
-    // Test with a non-entity reference.
-    $field = $this->prophesize(FieldInterface::class);
-    $field->getOriginalType()->willReturn('string');
-    $index = $this->prophesize(IndexInterface::class);
-    $index->getFields()->willReturn(array($field->reveal()));
-    $datasource = $this->prophesize(DatasourceInterface::class);
-    $datasource->getIndex()->willReturn($index->reveal());
-    $this->processor->alterPropertyDefinitions($properties, $datasource->reveal());
-    $this->assertArrayEquals($expected, $properties);
-
-    // Test with a field item, but not an entity reference field.
-    $field = $this->prophesize(FieldInterface::class);
-    $field->getOriginalType()->willReturn('field_item:string');
-    $index = $this->prophesize(IndexInterface::class);
-    $index->getFields()->willReturn([$field->reveal()]);
-    $datasource = $this->prophesize(DatasourceInterface::class);
-    $datasource->getIndex()->willReturn($index->reveal());
-    $this->processor->alterPropertyDefinitions($properties, $datasource->reveal());
-    $this->assertArrayEquals($expected, $properties);
-
-    // Test with an entity reference field.
-    $field = $this->prophesize(FieldInterface::class);
-    $field->getOriginalType()->willReturn('field_item:entity_reference');
-    $field->getLabel()->willReturn('Foo field');
-    $field->getFieldIdentifier()->willReturn('foo_field');
-    $index = $this->prophesize(IndexInterface::class);
-    $index->getFields()->willReturn([$field->reveal()]);
-    $datasource = $this->prophesize(DatasourceInterface::class);
-    $datasource->getIndex()->willReturn($index->reveal());
-    $this->processor->alterPropertyDefinitions($properties, $datasource->reveal());
-    $definition = array(
-      'label' => $this->translation->translate('Hierarchy of %field', array('%field' => 'Foo field')),
-      'description' => $this->translation->translate('The complete hierarchy for the entity reference', array()),
-      'type' => 'string',
-      'locked' => TRUE,
-    );
-    $expected = array(
-      'foo' => 'bar',
-      'search_api_hierarchy:foo_field' => new DataDefinition($definition),
-    );
-    $this->assertArrayEquals($expected, $properties);
-  }
-
-}