--- /dev/null
+<?php
+
+namespace Drupal\Tests\taxonomy\Functional;
+
+use Drupal\field\Entity\FieldStorageConfig;
+use Drupal\field\Entity\FieldConfig;
+
+/**
+ * Tests the settings of restricting term selection to a single vocabulary.
+ *
+ * @group taxonomy
+ */
+class TermEntityReferenceTest extends TaxonomyTestBase {
+
+ /**
+ * Modules to enable.
+ *
+ * @var array
+ */
+ public static $modules = ['entity_reference_test', 'entity_test'];
+
+ /**
+ * Tests an entity reference field restricted to a single vocabulary.
+ *
+ * Creates two vocabularies with a term, then set up the entity reference
+ * field to limit the target vocabulary to one of them, ensuring that
+ * the restriction applies.
+ */
+ public function testSelectionTestVocabularyRestriction() {
+
+ // Create two vocabularies.
+ $vocabulary = $this->createVocabulary();
+ $vocabulary2 = $this->createVocabulary();
+
+ $term = $this->createTerm($vocabulary);
+ $term2 = $this->createTerm($vocabulary2);
+
+ // Create an entity reference field.
+ $field_name = 'taxonomy_' . $vocabulary->id();
+ $field_storage = FieldStorageConfig::create([
+ 'field_name' => $field_name,
+ 'entity_type' => 'entity_test',
+ 'translatable' => FALSE,
+ 'settings' => [
+ 'target_type' => 'taxonomy_term',
+ ],
+ 'type' => 'entity_reference',
+ 'cardinality' => 1,
+ ]);
+ $field_storage->save();
+ $field = FieldConfig::create([
+ 'field_storage' => $field_storage,
+ 'entity_type' => 'entity_test',
+ 'bundle' => 'test_bundle',
+ 'settings' => [
+ 'handler' => 'default',
+ 'handler_settings' => [
+ // Restrict selection of terms to a single vocabulary.
+ 'target_bundles' => [
+ $vocabulary->id() => $vocabulary->id(),
+ ],
+ ],
+ ],
+ ]);
+ $field->save();
+
+ $handler = $this->container->get('plugin.manager.entity_reference_selection')->getSelectionHandler($field);
+ $result = $handler->getReferenceableEntities();
+
+ $expected_result = [
+ $vocabulary->id() => [
+ $term->id() => $term->getName(),
+ ],
+ ];
+
+ $this->assertIdentical($result, $expected_result, 'Terms selection restricted to a single vocabulary.');
+ }
+
+}