Add testutil package and function to generate a dagservice

util/testutil/gen.go

+package testutil
+
+import (
+	"testing"
+
+	ds "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-datastore"
+	bsrv "github.com/jbenet/go-ipfs/blockservice"
+	dag "github.com/jbenet/go-ipfs/merkledag"
+)
+
+func GetDAGServ(t testing.TB) dag.DAGService {
+	dstore := ds.NewMapDatastore()
+	bserv, err := bsrv.NewBlockService(dstore, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return dag.NewDAGService(bserv)
+}