anchor.diff:    Check(DirectoryExists(aFileName), 'Unable to locate directory: ' + aFileName);
   end;
   
  -procedure TAbTestCase.CheckFilesMatch(const aFileName1, aFileName2, Msg: string);
  +procedure TAbTestCase.CheckFilesMatch(const aFileName1, aFileName2: string;
  +  const aMsg: string = '');
   var
     Stream1, Stream2 : TStream;
   begin
  
positive.code:   try
      Stream2 := TFileStream.Create(AFileName2, fmOpenRead or fmShareDenyWrite);
      try
        CheckStreamMatch(Stream1, Stream2, Msg);
      finally
        Stream2.Free;
      end;
  
negative.code:   // to run winzip compatability tests
    stSpawn,
  {$ENDIF}
    Math, SysUtils,
    AbUtils;
  
  var
  