Update test entity

tests/modules/openapi_test/openapi_test.info.yml

 name: OpenApi Test Resources
 type: module
-description: Resource dependecies for running tests for the OpenApi Module.
+description: Resource dependencies for running tests for the OpenApi Module.
 core: 8.x
 core_version_requirement: '^8 || ^9'
 package: Testing

tests/modules/openapi_test/src/Entity/OpenApiTestEntity.php

@@ -83,6 +83,10 @@ class OpenApiTestEntity extends ContentEntityBase implements OpenApiTestEntityIn
       ->setDisplayConfigurable('form', TRUE)
       ->setDisplayConfigurable('view', TRUE);
 
+    $fields['json_data'] = BaseFieldDefinition::create('openapi_json_backed_test')
+      ->setLabel(t('JSON-backed data'))
+      ->setRequired(TRUE);
+
     if (\Drupal::moduleHandler()->moduleExists('menu_ui')) {
       $fields['menu_link'] = BaseFieldDefinition::create('entity_reference')
         ->setLabel(t('Menu link'))

tests/modules/openapi_test/src/Plugin/Field/FieldType/JsonBackedPropertiesItem.php

+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\openapi_test\Plugin\Field\FieldType;
+
+use Drupal\Core\Field\FieldStorageDefinitionInterface;
+use Drupal\Core\Field\Plugin\Field\FieldType\MapItem;
+use Drupal\Core\Serialization\Attribute\JsonSchema;
+
+/**
+ * Field type with JSON data storage.
+ *
+ * @FieldType(
+ *   id = "openapi_json_backed_test",
+ *   label = @Translation("JSON-backed field (test)"),
+ *   description = @Translation("A field containing JSON-backed properties."),
+ * )
+ */
+class JsonBackedPropertiesItem  extends MapItem {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function schema(FieldStorageDefinitionInterface $field_definition) {
+    return [
+      'columns' => [
+        'json_value' => [
+          'type' => 'json',
+        ],
+      ],
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  #[JsonSchema([
+    'type' => 'object',
+    'properties' => [
+      'property1' => ['type' => 'string'],
+      'property2' => ['type' => 'boolean'],
+    ],
+  ])]
+  public function getValue() {
+    return parent::getValue();
+  }
+
+}