diff --git a/Test/Unit/Parsing/FormBuilderTester.php b/Test/Unit/Parsing/FormBuilderTester.php
index <HASH>..<HASH> 100644
--- a/Test/Unit/Parsing/FormBuilderTester.php
+++ b/Test/Unit/Parsing/FormBuilderTester.php
@@ -62,6 +62,9 @@ class FormBuilderTester extends PHPMethodTester {
       $this->assertStatementIsParentCallAssignment(0, 'form', "The form builder's first statement is a call to the parent.");
     }
 
+    // All form builders implement an interface method.
+    $this->assertMethodDocblockHasInheritdoc();
+
     $this->assertReturnsVariable('form', "The form builder returns the completed form.");
 
     // Get the form element statements.
Added testing that form builder methods have the ‘inheritdoc’ tag.