Refactoring within TestFixtures, Anyone? NUnit and NUnitAddin

  I recently just started fooling around with the  NUnit and NUnitAddin framework for my current project.  See NUnitAddIn . I was doing the test-driven coding part when I realized that in this case, the framework always returns an incomplete test (a yellow mark when testing doCommon) when I try to refactor within this particular TestFixture: 
  
[TestFixture]  
public class MyObjectTest   {    
  MyObject myObject;      
 
  [SetUp]    
  public void SetUp()    
  {       
     myObject = new MyObject();      
    //...    
  }        
  [TearDown]    
  public void TearDown()    
  {      
     // ...    
  }
     
  [Test]    
  public void TestDoProcess()    
  {          
    Assertion.AssertEquals("GetRange",myObject.i,2);      
    doCommon(myObject);      
    myObject.DoProcess();      
    Assertion.AssertEquals("GetRange",myObject.i,1);    
  }      
 
  [Test]      
  public void TestDoReset()    
  {          
    Assertion.AssertEquals("GetRange",myObject.i,2) ;      
    doCommon(myObject);      
    myObject.DoReset();      
    Assertion.AssertEquals("GetRange",myObject.i,0);    
   }

    //this will not be ignored! 
   //[Ignore("This is not a test!")]    
   public void doCommon(MyObject anObject)    
  {     
   //do common processing on anObject               
    anObject.DoCommonProcess1();      
    anObject.DoCommonProcess2();      
    //...    
   }  
}   
 
I get the following:
  Running doCommon  TestCase
  'HotBlue.Utility.MyObjectTest.doCommon' not executed: Method doCommon's  signature is not correct: it must not have parameters. 
  

   Since the doCommon( ) member function was originally an ignored test case, adding the [Ignore("This is not a test!")] attribute will still result to the logging of a non-tested attribute, therefore I'd still get a yellow light. 

  My question is, what's the [Test] attribute for if it doesn't differentiate a normal member from a testable member?  What am I doing wrong, methinks? 

  It's a funky tool all in all, but can I refactor?