test navig test navig target manag instanc clean histori numtarget object target object numtarget numtarget target object target manag instanc set target target target manag instanc navig possibl equal target manag instanc navig forward possibl target manag instanc navig forward fail illeg state except target manag instanc navig backward equal target target manag instanc target target manag instanc navig possibl target manag instanc navig forward possibl target manag instanc navig backward equal target target manag instanc target target manag instanc navig possibl target manag instanc navig forward possibl target manag instanc navig backward target manag instanc navig forward possibl equal target manag instanc navig possibl target manag instanc navig backward fail illeg state except target manag instanc navig forward equal target target manag instanc target target manag instanc navig possibl target manag instanc navig forward possibl target manag instanc set target target target manag instanc navig possibl equal target manag instanc navig forward possibl target manag instanc navig forward fail illeg state except target manag instanc navig backward target manag instanc navig possibl target manag instanc navig forward possibl target manag instanc navig backward target manag instanc navig forward possibl equal target manag instanc navig possibl 