public function testNie()
{
$this->assertTrue(EsValidation::nie('X2546874S'));
$this->assertTrue(EsValidation::nie('Y2332323E'));
$this->assertTrue(EsValidation::nie('Z2548769Y'));
$this->assertFalse(EsValidation::nie('35489765Y'));
$this->assertFalse(EsValidation::nie('123456'));
}