.../Sql/SqlContentEntityStorageSchemaTest.php      | 73 +++++++++++++++++++++-
 1 file changed, 72 insertions(+), 1 deletion(-)

diff --git a/core/tests/Drupal/Tests/Core/Entity/Sql/SqlContentEntityStorageSchemaTest.php b/core/tests/Drupal/Tests/Core/Entity/Sql/SqlContentEntityStorageSchemaTest.php
index 3a28de0..1e033af 100644
--- a/core/tests/Drupal/Tests/Core/Entity/Sql/SqlContentEntityStorageSchemaTest.php
+++ b/core/tests/Drupal/Tests/Core/Entity/Sql/SqlContentEntityStorageSchemaTest.php
@@ -14,7 +14,6 @@
 
 /**
  * @coversDefaultClass \Drupal\Core\Entity\Sql\SqlContentEntityStorageSchema
- * @group Entity
  */
 class SqlContentEntityStorageSchemaTest extends UnitTestCase {
 
@@ -1056,6 +1055,78 @@ public function testDedicatedTableSchemaForEntityWithStringIdentifier() {
     );
   }
 
+  public function providerTestRequiresEntityDataMigration() {
+    $updated_entity_type_definition = $this->getMockBuilder('\Drupal\Core\Entity\EntityTypeInterface')
+      ->disableOriginalConstructor()
+      ->getMock();
+    $updated_entity_type_definition->expects($this->any())
+      ->method('getStorageClass')
+      ->willReturn('foo');
+    $original_entity_type_definition = $this->getMockBuilder('\Drupal\Core\Entity\EntityTypeInterface')
+      ->disableOriginalConstructor()
+      ->getMock();
+    $original_entity_type_definition->expects($this->any())
+      ->method('getStorageClass')
+      ->willReturn('foo');
+    $original_entity_type_definition_other_nonexisting = $this->getMockBuilder('\Drupal\Core\Entity\EntityTypeInterface')
+      ->disableOriginalConstructor()
+      ->getMock();
+    $original_entity_type_definition_other_nonexisting->expects($this->any())
+      ->method('getStorageClass')
+      ->willReturn('bar');
+    $original_entity_type_definition_other_existing = $this->getMockBuilder('\Drupal\Core\Entity\EntityTypeInterface')
+      ->disableOriginalConstructor()
+      ->getMock();
+    $original_entity_type_definition_other_existing->expects($this->any())
+      ->method('getStorageClass')
+      ->willReturn('\Drupal\Core\Entity\Sql\SqlContentEntityStorageSchema'); // A class that exists, *any* class.
+
+    return [
+      // Case 1: same storage class, ::hasData() === TRUE.
+      [$updated_entity_type_definition, $original_entity_type_definition, TRUE, TRUE],
+      // Case 2: same storage class, ::hasData() === FALSE.
+      [$updated_entity_type_definition, $original_entity_type_definition, FALSE, FALSE],
+      // Case 3: different storage class, original storage class does not exist.
+      [$updated_entity_type_definition, $original_entity_type_definition_other_nonexisting, NULL, TRUE],
+      // Case 4: different storage class, original storage class exists, ::hasData() === TRUE.
+      [$updated_entity_type_definition, $original_entity_type_definition_other_existing, TRUE, TRUE],
+      // Case 5: different storage class, original storage class exists, ::hasData() === FALSE.
+      [$updated_entity_type_definition, $original_entity_type_definition_other_existing, FALSE, FALSE],
+    ];
+  }
+
+  /**
+   * @covers ::requiresEntityDataMigration
+   *
+   * @dataProvider providerTestRequiresEntityDataMigration
+   */
+  public function testRequiresEntityDataMigration($updated_entity_type_definition, $original_entity_type_definition, $storage_has_data, $migration_required) {
+    $this->entityType = new ContentEntityType(array(
+      'id' => 'entity_test',
+      'entity_keys' => array('id' => 'id'),
+    ));
+
+    // Assert hasData() is not called when $storage_has_data === NULL.
+    $this->storage->expects($this->exactly(is_null($storage_has_data) ? 0 : 1))
+      ->method('hasData')
+      ->willReturn($storage_has_data);
+
+    $connection = $this->getMockBuilder('Drupal\Core\Database\Connection')
+      ->disableOriginalConstructor()
+      ->getMock();
+
+    $this->entityManager->expects($this->any())
+      ->method('createHandlerInstance')
+      ->willReturn($this->storage);
+
+    $this->storageSchema = $this->getMockBuilder('Drupal\Core\Entity\Sql\SqlContentEntityStorageSchema')
+      ->setConstructorArgs(array($this->entityManager, $this->entityType, $this->storage, $connection))
+      ->setMethods(array('installedStorageSchema'))
+      ->getMock();
+
+    $this->assertEquals($migration_required, $this->storageSchema->requiresEntityDataMigration($updated_entity_type_definition, $original_entity_type_definition));
+  }
+
   /**
    * Sets up the storage schema object to test.
    *