public function testNormalize()
{
$m = new Model();
$m->addField('name', ['type' => 'string']);
$m->addField('age', ['type' => 'int']);
$m->addField('data');
$m['name'] = '';
$this->assertSame('', $m['name']);
$m['age'] = '';
$this->assertSame(null, $m['age']);
$m['data'] = '';
$this->assertSame('', $m['data']);
}