diff --git a/tests/src/Kernel/Plugin/migrate/process/EntityLookupTest.php b/tests/src/Kernel/Plugin/migrate/process/EntityLookupTest.php
new file mode 100644
index 0000000..4713a3b
--- /dev/null
+++ b/tests/src/Kernel/Plugin/migrate/process/EntityLookupTest.php
@@ -0,0 +1,493 @@
+<?php
+
+namespace Drupal\Tests\migrate_plus\Kernel\Plugin\migrate\process;
+
+use Drupal\node\Entity\NodeType;
+use Drupal\migrate\MigrateExecutable;
+use Drupal\KernelTests\KernelTestBase;
+use Drupal\taxonomy\Entity\Vocabulary;
+use Drupal\Core\Language\LanguageInterface;
+use Drupal\migrate\MigrateMessageInterface;
+use Drupal\Core\Field\FieldStorageDefinitionInterface;
+use Drupal\field\Tests\EntityReference\EntityReferenceTestTrait;
+
+/**
+ * Tests the migration plugin.
+ *
+ * @coversDefaultClass \Drupal\migrate_plus\Plugin\migrate\process\EntityLookup
+ * @group migrate_plus
+ */
+class EntityLookupTest extends KernelTestBase implements MigrateMessageInterface {
+
+  use EntityReferenceTestTrait;
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $modules = [
+    'migrate_plus',
+    'migrate',
+    'user',
+    'system',
+    'node',
+    'taxonomy',
+    'field',
+    'text',
+    'filter',
+  ];
+
+  /**
+   * The bundle used in this test.
+   *
+   * @var string
+   */
+  protected $bundle = 'page';
+
+  /**
+   * The name of the field used in this test.
+   *
+   * @var string
+   */
+  protected $fieldName = 'field_entity_reference';
+
+  /**
+   * The vocabulary id.
+   *
+   * @var string
+   */
+  protected $vocabulary = 'fruit';
+
+  /**
+   * The migration plugin manager.
+   *
+   * @var \Drupal\migrate\Plugin\MigrationPluginManager
+   */
+  protected $migrationPluginManager;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+
+    // Create article content type.
+    $values = [
+      'type' => $this->bundle,
+      'name' => 'Page',
+    ];
+    $node_type = NodeType::create($values);
+    $node_type->save();
+
+    $this->installEntitySchema('node');
+    $this->installEntitySchema('taxonomy_term');
+    $this->installEntitySchema('taxonomy_vocabulary');
+    $this->installEntitySchema('user');
+    $this->installSchema('system', ['sequences']);
+    $this->installSchema('user', 'users_data');
+    $this->installConfig($this->modules);
+
+    // Create a vocabulary.
+    $vocabulary = Vocabulary::create([
+      'name' => $this->vocabulary,
+      'description' => $this->vocabulary,
+      'vid' => $this->vocabulary,
+      'langcode' => LanguageInterface::LANGCODE_NOT_SPECIFIED,
+    ]);
+    $vocabulary->save();
+
+    // Create a field.
+    $this->createEntityReferenceField(
+      'node',
+      $this->bundle,
+      $this->fieldName,
+      'Term reference',
+      'taxonomy_term',
+      'default',
+      ['target_bundles' => [$this->vocabulary]],
+      FieldStorageDefinitionInterface::CARDINALITY_UNLIMITED
+    );
+
+    $this->migrationPluginManager = \Drupal::service('plugin.manager.migration');
+  }
+
+  /**
+   * Tests generating an entity.
+   *
+   * @dataProvider transformDataProvider
+   *
+   * @covers ::transform
+   */
+  public function testTransform(array $definition, array $expected, array $preSeed = []) {
+    // Pre seed some test data.
+    foreach ($preSeed as $storageName => $values) {
+      // If the first element of $values is an array, create multiple entities.
+      // Otherwise, create just one entity.
+      if (isset($values[0])) {
+        foreach ($values as $itemValues) {
+          $this->createTestData($storageName, $itemValues);
+        }
+      }
+      else {
+        $this->createTestData($storageName, $values);
+      }
+    }
+
+    /** @var Drupal\migrate\Plugin\Migration $migration */
+    $migration = $this->migrationPluginManager->createStubMigration($definition);
+    /** @var EntityStorageBase $storage */
+    $storage = $this->readAttribute($migration->getDestinationPlugin(), 'storage');
+    $migrationExecutable = (new MigrateExecutable($migration, $this));
+    $migrationExecutable->import();
+
+    foreach ($expected as $row) {
+      $entity = $storage->load($row['id']);
+      $properties = array_diff_key($row, array_flip(['id']));
+      foreach ($properties as $property => $value) {
+        if (is_array($value)) {
+          if (empty($value)) {
+            $this->assertEmpty($entity->{$property}->getValue(), "Expected value is 'unset' but field $property is set.");
+          }
+          else {
+            // Check if we're testing multiple values in one field. If so, loop
+            // through them one-by-one and check that they're present in the
+            // $entity.
+            if (isset($value[0])) {
+              foreach ($value as $valueID => $valueToCheck) {
+                foreach ($valueToCheck as $key => $expectedValue) {
+                  if (empty($expectedValue)) {
+                    $this->assertEmpty($entity->{$property}[$valueID]->getValue(), "Expected value is empty but field $property, index $valueID is not empty.");
+                  }
+                  elseif ($entity->{$property}[$valueID]->getValue()) {
+                    $this->assertEquals($expectedValue, $entity->{$property}[$valueID]->entity->$key->value);
+                  }
+                  else {
+                    $this->fail("Expected value: $expectedValue does not exist in $property, index $valueID.");
+                  }
+                }
+              }
+            }
+            // If we get to this point, we're only checking a
+            // single field value.
+            else {
+              foreach ($value as $key => $expectedValue) {
+                if (empty($expectedValue)) {
+                  $this->assertEmpty($entity->{$property}->getValue(), "Expected value is empty but field $property is not empty.");
+                }
+                elseif ($entity->{$property}->getValue()) {
+                  $this->assertEquals($expectedValue, $entity->{$property}[0]->entity->$key->value);
+                }
+                else {
+                  $this->fail("Expected value: $expectedValue does not exist in $property.");
+                }
+              }
+            }
+          }
+        }
+        else {
+          $this->assertNotEmpty($entity, 'Entity with label ' . $row[$property] . ' is empty');
+          $this->assertEquals($row[$property], $entity->label());
+        }
+      }
+    }
+  }
+
+  /**
+   * Provides multiple migration definitions for "transform" test.
+   */
+  public function transformDataProvider() {
+    return [
+      'lookup single existing term returns correct term' => [
+        'definition' => [
+          'source' => [
+            'plugin' => 'embedded_data',
+            'data_rows' => [
+              [
+                'id' => 1,
+                'title' => 'content item 1',
+                'term' => 'Grapes',
+              ],
+            ],
+            'ids' => [
+              'id' => ['type' => 'integer'],
+            ],
+          ],
+          'process' => [
+            'id' => 'id',
+            'type' => [
+              'plugin' => 'default_value',
+              'default_value' => $this->bundle,
+            ],
+            'title' => 'title',
+            $this->fieldName => [
+              'plugin' => 'entity_lookup',
+              'source' => 'term',
+            ],
+          ],
+          'destination' => [
+            'plugin' => 'entity:node',
+          ],
+        ],
+        'expected' => [
+          'row 1' => [
+            'id' => 1,
+            'title' => 'content item 1',
+            $this->fieldName => [
+              'tid' => 1,
+              'name' => 'Grapes',
+            ],
+          ],
+        ],
+        'pre seed' => [
+          'taxonomy_term' => [
+            'name' => 'Grapes',
+            'vid' => $this->vocabulary,
+            'langcode' => LanguageInterface::LANGCODE_NOT_SPECIFIED,
+          ],
+        ],
+      ],
+      'lookup single missing term returns null value' => [
+        'definition' => [
+          'source' => [
+            'plugin' => 'embedded_data',
+            'data_rows' => [
+              [
+                'id' => 1,
+                'title' => 'content item 1',
+                'term' => 'Apple',
+              ],
+            ],
+            'ids' => [
+              'id' => ['type' => 'integer'],
+            ],
+          ],
+          'process' => [
+            'id' => 'id',
+            'type' => [
+              'plugin' => 'default_value',
+              'default_value' => $this->bundle,
+            ],
+            'title' => 'title',
+            $this->fieldName => [
+              'plugin' => 'entity_lookup',
+              'source' => 'term',
+            ],
+          ],
+          'destination' => [
+            'plugin' => 'entity:node',
+          ],
+        ],
+        'expected' => [
+          'row 1' => [
+            'id' => 1,
+            'title' => 'content item 1',
+            $this->fieldName => [],
+          ],
+        ],
+        'pre seed' => [
+          'taxonomy_term' => [
+            'name' => 'Grapes',
+            'vid' => $this->vocabulary,
+            'langcode' => LanguageInterface::LANGCODE_NOT_SPECIFIED,
+          ],
+        ],
+      ],
+      'lookup multiple existing terms returns correct terms' => [
+        'definition' => [
+          'source' => [
+            'plugin' => 'embedded_data',
+            'data_rows' => [
+              [
+                'id' => 1,
+                'title' => 'content item 1',
+                'term' => [
+                  'Grapes',
+                  'Apples',
+                ],
+              ],
+            ],
+            'ids' => [
+              'id' => ['type' => 'integer'],
+            ],
+          ],
+          'process' => [
+            'id' => 'id',
+            'title' => 'title',
+            'type' => [
+              'plugin' => 'default_value',
+              'default_value' => $this->bundle,
+            ],
+            $this->fieldName => [
+              'plugin' => 'entity_lookup',
+              'source' => 'term',
+            ],
+          ],
+          'destination' => [
+            'plugin' => 'entity:node',
+          ],
+        ],
+        'expected' => [
+          'row 1' => [
+            'id' => 1,
+            'title' => 'content item 1',
+            $this->fieldName => [
+              [
+                'tid' => 1,
+                'name' => 'Grapes',
+              ],
+              [
+                'tid' => 2,
+                'name' => 'Apples',
+              ],
+            ],
+          ],
+        ],
+        'pre seed' => [
+          'taxonomy_term' => [
+            [
+              'name' => 'Grapes',
+              'vid' => $this->vocabulary,
+              'langcode' => LanguageInterface::LANGCODE_NOT_SPECIFIED,
+            ],
+            [
+              'name' => 'Apples',
+              'vid' => $this->vocabulary,
+              'langcode' => LanguageInterface::LANGCODE_NOT_SPECIFIED,
+            ],
+          ],
+        ],
+      ],
+      'lookup multiple mixed terms returns correct terms' => [
+        'definition' => [
+          'source' => [
+            'plugin' => 'embedded_data',
+            'data_rows' => [
+              [
+                'id' => 1,
+                'title' => 'content item 1',
+                'term' => [
+                  'Grapes',
+                  'Pears',
+                ],
+              ],
+            ],
+            'ids' => [
+              'id' => ['type' => 'integer'],
+            ],
+          ],
+          'process' => [
+            'id' => 'id',
+            'title' => 'title',
+            'type' => [
+              'plugin' => 'default_value',
+              'default_value' => $this->bundle,
+            ],
+            $this->fieldName => [
+              'plugin' => 'entity_lookup',
+              'source' => 'term',
+            ],
+          ],
+          'destination' => [
+            'plugin' => 'entity:node',
+          ],
+        ],
+        'expected' => [
+          'row 1' => [
+            'id' => '1',
+            'title' => 'content item 1',
+            $this->fieldName => [
+              [
+                'tid' => 1,
+                'name' => 'Grapes',
+              ],
+            ],
+          ],
+        ],
+        'pre seed' => [
+          'taxonomy_term' => [
+            [
+              'name' => 'Grapes',
+              'vid' => $this->vocabulary,
+              'langcode' => LanguageInterface::LANGCODE_NOT_SPECIFIED,
+            ],
+            [
+              'name' => 'Apples',
+              'vid' => $this->vocabulary,
+              'langcode' => LanguageInterface::LANGCODE_NOT_SPECIFIED,
+            ],
+          ],
+        ],
+      ],
+      'lookup with empty term value returns no terms' => [
+        'definition' => [
+          'source' => [
+            'plugin' => 'embedded_data',
+            'data_rows' => [
+              [
+                'id' => 1,
+                'title' => 'content item 1',
+                'term' => [],
+              ],
+            ],
+            'ids' => [
+              'id' => ['type' => 'integer'],
+            ],
+          ],
+          'process' => [
+            'id' => 'id',
+            'title' => 'title',
+            'type' => [
+              'plugin' => 'default_value',
+              'default_value' => $this->bundle,
+            ],
+            $this->fieldName => [
+              'plugin' => 'entity_lookup',
+              'source' => 'term',
+            ],
+          ],
+          'destination' => [
+            'plugin' => 'entity:node',
+          ],
+        ],
+        'expected' => [
+          'row 1' => [
+            'id' => 1,
+            'title' => 'content item 1',
+            $this->fieldName => [],
+          ],
+        ],
+        'pre seed' => [
+          'taxonomy_term' => [
+            'name' => 'Grapes',
+            'vid' => $this->vocabulary,
+            'langcode' => LanguageInterface::LANGCODE_NOT_SPECIFIED,
+          ],
+        ],
+      ],
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function display($message, $type = 'status') {
+    $this->assertTrue($type == 'status', $message);
+  }
+
+  /**
+   * Create pre-seed test data.
+   *
+   * @param string $storageName
+   *   The storage manager to create.
+   * @param array $values
+   *   The values to use when creating the entity.
+   */
+  private function createTestData($storageName, array $values) {
+    /** @var \Drupal\Core\Entity\ContentEntityStorageInterface $storage */
+    $storage = $this->container
+      ->get('entity_type.manager')
+      ->getStorage($storageName);
+    $entity = $storage->create($values);
+    $entity->save();
+  }
+
+}