Add assertions for boolean values

tests/TestCase/Validation/ValidationTest.php

@@ -2971,6 +2971,8 @@ class ValidationTest extends TestCase
         $this->assertFalse(Validation::isInteger([]));
         $this->assertFalse(Validation::isInteger(new \StdClass));
         $this->assertFalse(Validation::isInteger('2 bears'));
+        $this->assertFalse(Validation::isInteger(true));
+        $this->assertFalse(Validation::isInteger(false));
     }
 
     /**