Add Validator::regex()

Foo

src/Validation/Validator.php

@@ -1684,6 +1684,25 @@ public function isPresenceRequired($field, $newRecord)
         return !$this->_checkPresence($this->field($field), $context);
     }
 
+    /**
+     * Returns whether or not a field matches against a regular expression.
+     *
+     * @param string $field Field name.
+     * @param string $regex Regular expression.
+     * @param string|null $message The error message when the rule fails.
+     * @param string|callable|null $when Either 'create' or 'update' or a callable that returns
+     *   true when the validation rule should be applied.
+     * @return bool
+     */
+    public function regex($field, $regex, $message = null, $when = null)
+    {
+        $extra = array_filter(['on' => $when, 'message' => $message]);
+
+        return $this->add($field, 'regex', $extra + [
+            'rule' => ['custom', $regex]
+        ]);
+    }
+
     /**
      * Returns false if any validation for the passed rule set should be stopped
      * due to the field missing in the data array

tests/TestCase/Validation/ValidatorTest.php

@@ -1845,6 +1845,19 @@ public function testHasAtMost()
         $this->assertNotEmpty($validator->errors(['things' => ['_ids' => [1, 2, 3, 4]]]));
     }
 
+    /**
+     * Tests the regex proxy method
+     *
+     * @return void
+     */
+    public function testRegex()
+    {
+        $validator = new Validator();
+        $this->assertProxyMethod($validator, 'regex', '/(?<!\\S)\\d++(?!\\S)/', ['/(?<!\\S)\\d++(?!\\S)/'], 'custom');
+        $this->assertEmpty($validator->errors(['username' => '123']));
+        $this->assertNotEmpty($validator->errors(['username' => 'Foo']));
+    }
+
     /**
      * Tests that a rule in the Validator class exists and was configured as expected.
      *