Add digits rule

Author: phannaly

src/Rules/Digits.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace Rakit\Validation\Rules;
+
+use Rakit\Validation\Rule;
+
+class Digits extends Rule
+{
+
+    protected $message = "The :attribute must be numeric and must have an exact length of :length";
+
+    protected $fillable_params = ['length'];
+
+    public function check($value)
+    {
+    	$this->requireParameters($this->fillable_params);
+
+        $length = (int) $this->parameter('length');
+
+        return ! preg_match('/[^0-9]/', $value)
+                    && strlen((string) $value) == $length;
+    }
+
+}

src/Validator.php

@@ -107,6 +107,7 @@ protected function registerBaseValidators()
             'lowercase'                 => new Rules\Lowercase,
             'uppercase'                 => new Rules\Uppercase,
             'json'                      => new Rules\Json,
+            'digits'                      => new Rules\Digits,
             'defaults'                  => new Rules\Defaults,
             'default'                   => new Rules\Defaults, // alias of defaults
         ];

tests/Rules/DigitsTest.php

@@ -0,0 +1,27 @@
+<?php
+
+use Rakit\Validation\Rules\Digits;
+
+class DigitsTest extends PHPUnit_Framework_TestCase
+{
+
+    public function setUp()
+    {
+        $this->rule = new Digits;
+    }
+
+    public function testValids()
+    {
+        $this->assertTrue($this->rule->fillParameters([4])->check(1243));
+        $this->assertTrue($this->rule->fillParameters([6])->check(124567));
+        $this->assertTrue($this->rule->fillParameters([3])->check('123'));
+    }
+
+    public function testInvalids()
+    {
+        $this->assertFalse($this->rule->fillParameters([7])->check(12345678));
+        $this->assertFalse($this->rule->fillParameters([4])->check(12));      
+        $this->assertFalse($this->rule->fillParameters([3])->check('foo'));      
+    }
+
+}