public function testVisititorVisitsChildren()
 {
     $id = 'foreignKeyNode';
     $event = $this->getMockBuilder('Symfony\\Component\\EventDispatcher\\EventDispatcherInterface')->getMock();
     $foreignKey = new ForeignKeyNode($id, $event);
     $child_a = $this->getMockBuilder('Faker\\Tests\\Engine\\DB\\Mock\\MockNode')->disableOriginalConstructor()->getMock();
     $child_a->expects($this->once())->method('acceptVisitor')->with($this->isInstanceOf('Faker\\Components\\Engine\\Common\\Visitor\\BasicVisitor'));
     $child_b = $this->getMockBuilder('Faker\\Tests\\Engine\\DB\\Mock\\MockNode')->disableOriginalConstructor()->getMock();
     $child_b->expects($this->once())->method('acceptVisitor')->with($this->isInstanceOf('Faker\\Components\\Engine\\Common\\Visitor\\BasicVisitor'));
     $visitor = $this->getMockBuilder('Faker\\Components\\Engine\\Common\\Visitor\\BasicVisitor')->disableOriginalConstructor()->getMock();
     $foreignKey->addChild($child_a);
     $foreignKey->addChild($child_b);
     $foreignKey->acceptVisitor($visitor);
 }