add integer rule

README.md

@@ -287,6 +287,7 @@ Below is list of all available validation rules
 * [digits](#rule-digits)
 * [digits_between](#rule-digits_between)
 * [url](#rule-url)
+* [integer](#rule-integer)
 * [ip](#rule-ip)
 * [ipv4](#rule-ipv4)
 * [ipv6](#rule-ipv6)
@@ -513,6 +514,10 @@ $validation = $validator->validate($inputs, [
 > For common URL scheme and mailto, we combine `FILTER_VALIDATE_URL` to validate URL format and `preg_match` to validate it's scheme. 
   Except for JDBC URL, currently it just check a valid JDBC scheme.
 
+<a id="rule-integer"></a>
+#### integer
+The field under this rule must be integer.
+
 <a id="rule-ip"></a>
 #### ip
 

src/Rules/Integer.php

@@ -0,0 +1,17 @@
+<?php
+
+namespace Rakit\Validation\Rules;
+
+use Rakit\Validation\Rule;
+
+class Integer extends Rule
+{
+
+    protected $message = "The :attribute must be integer";
+
+    public function check($value)
+    {
+        return filter_var($value, FILTER_VALIDATE_INT) !== false;
+    }
+
+}

src/Validator.php

@@ -90,6 +90,7 @@ protected function registerBaseValidators()
             'max'                       => new Rules\Max,
             'between'                   => new Rules\Between,
             'url'                       => new Rules\Url,
+            'integer'                   => new Rules\Integer,
             'ip'                        => new Rules\Ip,
             'ipv4'                      => new Rules\Ipv4,
             'ipv6'                      => new Rules\Ipv6,

tests/Rules/IntegerTest.php

@@ -0,0 +1,33 @@
+<?php
+
+use Rakit\Validation\Rules\Integer;
+
+class IntegerTest extends PHPUnit_Framework_TestCase
+{
+
+    public function setUp()
+    {
+        $this->rule = new Integer;
+    }
+
+    public function testValids()
+    {
+        $this->assertTrue($this->rule->check(0));
+        $this->assertTrue($this->rule->check('0'));
+        $this->assertTrue($this->rule->check('123'));
+        $this->assertTrue($this->rule->check('-123'));
+        $this->assertTrue($this->rule->check(123));
+        $this->assertTrue($this->rule->check(-123));
+
+    }
+
+    public function testInvalids()
+    {
+        $this->assertFalse($this->rule->check('foo123'));
+        $this->assertFalse($this->rule->check('123foo'));
+        $this->assertFalse($this->rule->check([123]));
+        $this->assertFalse($this->rule->check('123.456'));
+        $this->assertFalse($this->rule->check('-123.456'));
+    }
+
+}