Added support for non-mandatory fields. Fixes issue #13.

src/Valitron/Validator.php

@@ -498,6 +498,11 @@ class Validator
             foreach($v['fields'] as $field) {
                 $value = isset($this->_fields[$field]) ? $this->_fields[$field] : null;
 
+                // Don't validate if the field is not required and the value is empty
+                if ($v['rule'] !== 'required' && !$this->hasRule('required', $field) && $value == '') {
+                    continue;
+                }
+
                 // Callback is user-specified or assumed method on class
                 if(isset(static::$_rules[$v['rule']])) {
                     $callback = static::$_rules[$v['rule']];
@@ -511,9 +516,22 @@ class Validator
                 }
             }
         }
+
         return count($this->errors()) === 0;
     }
 
+    /**
+     * Determine whether a field is being validated by the given rule.
+     * 
+     * @param string $name The name of the rule
+     * @param string $field The name of the field
+     * @return boolean
+     */
+    protected function hasRule($name, $field)
+    {
+        return isset($this->_validations[$name]) && in_array($field, $this->_validations[$name]['fields']);
+    }
+
     /**
      * Register new validation rule callback
      */

tests/Valitron/Validate.php

@@ -63,7 +63,7 @@ class ValidateTest extends \PHPUnit_Framework_TestCase
             'email' => array('Email should be a valid email address')
         );
 
-        $v = new Validator(array());
+        $v = new Validator(array('name' => '', 'email' => '$'));
         $v->rule('required', 'name')->message('{field} is required');
         $v->rule('email', 'email')->message('{field} should be a valid email address');
 
@@ -128,7 +128,7 @@ class ValidateTest extends \PHPUnit_Framework_TestCase
 
     public function testDifferentInvalid()
     {
-        $v = new Validator(array('test1' => 'test', 'test2' => 'test'));
+        $v = new Validator(array('foo' => 'baz', 'bar' => 'baz'));
         $v->rule('different', 'foo', 'bar');
         $this->assertFalse($v->validate());
     }
@@ -385,6 +385,16 @@ class ValidateTest extends \PHPUnit_Framework_TestCase
         $this->assertFalse($v->validate());
     }
 
+    /**
+     * @group issue-13
+     */
+    public function testDateValidWhenEmptyButNotRequired()
+    {
+        $v = new Validator(array('date' => ''));
+        $v->rule('date', 'date');
+        $this->assertTrue($v->validate());
+    }
+
     public function testDateFormatValid()
     {
         $v = new Validator(array('date' => '2013-01-27'));