/**
  * @test
  */
 public function addOrUpdateOverridesAnExistingKey()
 {
     $this->viewHelperVariableContainer->add('NamelessCoder\\Fluid\\ViewHelper\\NonExistent', 'someKey', 'value1');
     $this->viewHelperVariableContainer->addOrUpdate('NamelessCoder\\Fluid\\ViewHelper\\NonExistent', 'someKey', 'value2');
     $this->assertEquals($this->viewHelperVariableContainer->get('NamelessCoder\\Fluid\\ViewHelper\\NonExistent', 'someKey'), 'value2');
 }