public function testSerializationDeserialization()
{
$obj = new PaymentHistory(self::getJson());
$this->assertNotNull($obj);
$this->assertNotNull($obj->getPayments());
$this->assertNotNull($obj->getCount());
$this->assertNotNull($obj->getNextId());
$this->assertEquals(self::getJson(), $obj->toJson());
return $obj;
}