diff --git a/form/unit_testing.rst b/form/unit_testing.rst
index 639e5936f1d..9f20accdb53 100644
--- a/form/unit_testing.rst
+++ b/form/unit_testing.rst
@@ -185,10 +185,10 @@ allows you to return a list of extensions to register::
 
         protected function getExtensions()
         {
-            $this->validator = $this->createMock(ValidatorInterface::class);
+            $validator = $this->createMock(ValidatorInterface::class);
             // use getMock() on PHPUnit 5.3 or below
-            // $this->validator = $this->getMock(ValidatorInterface::class);
-            $this->validator
+            // $validator = $this->getMock(ValidatorInterface::class);
+            $validator
                 ->method('validate')
                 ->will($this->returnValue(new ConstraintViolationList()));
             $validator