--- /dev/null
+<?php
+
+namespace Drupal\Tests\serialization\Unit\Normalizer;
+
+use Drupal\Core\TypedData\DataDefinitionInterface;
+use Drupal\Core\TypedData\TypedDataInterface;
+
+/**
+ * Trait that provides mocked typed data objects.
+ */
+trait InternalTypedDataTestTrait {
+
+ /**
+ * Gets a typed data property.
+ *
+ * @param bool $internal
+ * Whether the typed data property is internal.
+ *
+ * @return \Drupal\Core\TypedData\TypedDataInterface
+ * The typed data property.
+ */
+ protected function getTypedDataProperty($internal = TRUE) {
+ $definition = $this->prophesize(DataDefinitionInterface::class);
+ $definition->isInternal()
+ ->willReturn($internal)
+ ->shouldBeCalled();
+ $definition = $definition->reveal();
+
+ $property = $this->prophesize(TypedDataInterface::class);
+ $property->getDataDefinition()
+ ->willReturn($definition)
+ ->shouldBeCalled();
+ return $property->reveal();
+ }
+
+}