Add email assertion (webmozarts#113)

README.md

@@ -157,6 +157,7 @@ Method                                              | Description
 `ip($value, $message = '')`                         | Check that a string is a valid IP (either IPv4 or IPv6)
 `ipv4($value, $message = '')`                       | Check that a string is a valid IPv4
 `ipv6($value, $message = '')`                       | Check that a string is a valid IPv6
+`email($value, $message = '')`                      | Check that a string is a valid e-mail address
 `notWhitespaceOnly($value, $message = '')`          | Check that a string contains at least one non-whitespace character
 
 ### File Assertions

src/Assert.php

@@ -50,6 +50,7 @@
  * @method static void nullOrIp($value, $message = '')
  * @method static void nullOrIpv4($value, $message = '')
  * @method static void nullOrIpv6($value, $message = '')
+ * @method static void nullOrEmail($value, $message = '')
  * @method static void nullOrUniqueValues($values, $message = '')
  * @method static void nullOrEq($value, $expect, $message = '')
  * @method static void nullOrNotEq($value, $expect, $message = '')
@@ -131,6 +132,7 @@
  * @method static void allIp($values, $message = '')
  * @method static void allIpv4($values, $message = '')
  * @method static void allIpv6($values, $message = '')
+ * @method static void allEmail($values, $message = '')
  * @method static void allUniqueValues($values, $message = '')
  * @method static void allEq($values, $expect, $message = '')
  * @method static void allNotEq($values, $expect, $message = '')
@@ -501,6 +503,16 @@ public static function ipv6($value, $message = '')
         }
     }
 
+    public static function email($value, $message = '')
+    {
+        if (false === filter_var($value, FILTER_VALIDATE_EMAIL)) {
+            static::reportInvalidArgument(sprintf(
+                $message ?: 'Expected a value to be a valid e-mail address. Got %s',
+                static::valueToString($value)
+            ));
+        }
+    }
+
     public static function uniqueValues(array $values, $message = '')
     {
         $allValues = count($values);

tests/AssertTest.php

@@ -476,6 +476,10 @@ public function getTests()
             array('ipv6', array(array()), false),
             array('ipv6', array(null), false),
             array('ipv6', array(false), false),
+            array('email', array('foo'), false),
+            array('email', array(123), false),
+            array('email', array('foo.com'), false),
+            array('email', array('[email protected]'), true),
             array('uniqueValues', array(array('qwerty', 'qwerty')), false),
             array('uniqueValues', array(array('asdfg', 'qwerty')), true),
             array('uniqueValues', array(array(123, '123')), false),