--- /dev/null
+<?php
+
+namespace Drupal\entity_test\Entity;
+
+use Drupal\Core\Entity\EntityTypeInterface;
+use Drupal\Core\Field\BaseFieldDefinition;
+
+/**
+ * An entity used for testing map base field values.
+ *
+ * @ContentEntityType(
+ * id = "entity_test_map_field",
+ * label = @Translation("Entity Test map field"),
+ * base_table = "entity_test_map_field",
+ * entity_keys = {
+ * "uuid" = "uuid",
+ * "id" = "id",
+ * "label" = "name",
+ * "langcode" = "langcode",
+ * },
+ * admin_permission = "administer entity_test content",
+ * )
+ */
+class EntityTestMapField extends EntityTest {
+
+ /**
+ * {@inheritdoc}
+ */
+ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
+ $fields = parent::baseFieldDefinitions($entity_type);
+
+ $fields['data'] = BaseFieldDefinition::create('map')
+ ->setLabel(t('Data'))
+ ->setDescription(t('A serialized array of additional data.'));
+
+ return $fields;
+ }
+
+}