public function testSerializeEmbedOneTargetDocument()
 {
     $apple = new EmbeddedApple();
     $apple->setColor('red');
     $fruitBowl = new FruitBowl();
     $fruitBowl->setEmbeddedSingleFruitTarget($apple);
     $correct = ['embeddedSingleFruitTarget' => ['color' => 'red']];
     $array = $this->serializer->toArray($fruitBowl);
     $this->assertEquals($correct, $array);
 }