public function testWritePropertyIsIgnoredIfPropertyPathIsNull()
 {
     $author = new Author();
     $author->child = $child = new Author();
     $standaloneChild = new Author();
     $form = new Form('child');
     $form->setData($standaloneChild);
     $form->setPropertyPath(null);
     $form->writeProperty($author);
     // $author->child was not modified
     $this->assertSame($child, $author->child);
 }