u"github.com/jbenet/go-ipfs/util")funcTestBlockReturnsErr(t*testing.T){off:=NewOfflineExchange()_,err:=off.Block(context.Background(),u.Key("foo"))iferr!=nil{return// as desired}t.Fail()}funcTestHasBlockReturnsNil(t*testing.T){off:=NewOfflineExchange()