test: add test that object store folder copy preserves folder size

Signed-off-by: Robin Appelman <robin@icewind.nl>

Author: icewind1991

tests/lib/Files/ObjectStore/ObjectStoreStorageTest.php

@@ -262,4 +262,17 @@ public function testCopyGrantsPermissions(): void {
 		$this->assertTrue($cache->inCache('new.txt'));
 		$this->assertEquals(\OCP\Constants::PERMISSION_ALL, $instance->getPermissions('new.txt'));
 	}
+
+	public function testCopyFolderSize(): void {
+		$cache = $this->instance->getCache();
+
+		$this->instance->mkdir('source');
+		$this->instance->file_put_contents('source/test.txt', 'foo');
+		$this->instance->getUpdater()->update('source/test.txt');
+		$this->assertEquals(3, $cache->get('source')->getSize());
+
+		$this->assertTrue($this->instance->copy('source', 'target'));
+
+		$this->assertEquals(3, $cache->get('target')->getSize());
+	}
 }