Added test for structs within structs
Added test for structs within structs

ggaaooppeenngg/cachemap,robfig/go-cache,nothingmuch/go-cache,pmylund/go-cache,dustin/go-cache,cognusion/go-cache-lru,zj8487/go-cache,patrickmn/go-cache,jiangjin/go-cache,yxd-hde/go-cache