add DNI generator to spanis person

src/Faker/Provider/es_ES/Person.php

@@ -4,6 +4,8 @@
 
 class Person extends \Faker\Provider\Person
 {
+    private static $crcMap=array('T', 'R', 'W', 'A', 'G', 'M', 'Y', 'F', 'P', 'D', 'X', 'B', 'N', 'J', 'Z', 'S', 'Q', 'V', 'H', 'L', 'C', 'K', 'E', 'T');
+
     protected static $maleNameFormats = array(
         '{{firstNameMale}} {{lastName}}',
         '{{firstNameMale}} {{lastName}}',
@@ -68,4 +70,12 @@ public static function suffix()
     {
         return static::randomElement(static::$suffix);
     }
+
+    public static function dni()
+    {
+        $number=static::numerify('########');
+
+        $letter=self::$crcMap[$number%23];
+        return $number.$letter;
+    }
 }

test/Faker/Provider/es_ES/PersonTest.php

@@ -0,0 +1,38 @@
+<?php
+
+namespace Faker\Test\Provider\es_ES;
+
+use Faker\Generator;
+use Faker\Provider\es_ES\Person;
+
+class PersonTest extends \PHPUnit_Framework_TestCase
+{
+    public function setUp()
+    {
+        $faker = new Generator();
+        $faker->seed(1);
+        $faker->addProvider(new Person($faker));
+        $this->faker = $faker;
+    }
+
+    public function testDNI()
+    {
+        $dni = $this->faker->dni;
+        $this->assertTrue($this->isValidDNI($dni));
+    }
+
+    // validation taken from http://kiwwito.com/php-function-for-spanish-dni-nie-validation/
+    public function isValidDNI($string)
+    {
+        if (strlen($string) != 9 ||
+            preg_match('/^[XYZ]?([0-9]{7,8})([A-Z])$/i', $string, $matches) !== 1) {
+            return false;
+        }
+
+        $map = 'TRWAGMYFPDXBNJZSQVHLCKE';
+
+        list(, $number, $letter) = $matches;
+
+        return strtoupper($letter) === $map[((int) $number) % 23];
+    }
+}