public function testAddAuthor()
{
$value = new AuthorValue();
$value->authors[] = $this->authors[0];
self::assertSame(1, $this->authors[0]->id);
self::assertSame(1, count($value->authors));
$this->authors[1]->id = 10;
$value->authors[] = $this->authors[1];
self::assertSame(10, $this->authors[1]->id);
$this->authors[2]->id = -1;
$value->authors[] = $this->authors[2];
self::assertSame($this->authors[1]->id + 1, $this->authors[2]->id);
self::assertSame(3, count($value->authors));
}