add a test in merkledag to exercise GetBlocks

merkledag/merkledag_test.go

-package merkledag
+package merkledag_test
 
 import (
+	"bytes"
 	"fmt"
+	"io"
+	"io/ioutil"
 	"testing"
 
+	bserv "github.com/jbenet/go-ipfs/blockservice"
+	bs "github.com/jbenet/go-ipfs/exchange/bitswap"
+	tn "github.com/jbenet/go-ipfs/exchange/bitswap/testnet"
+	imp "github.com/jbenet/go-ipfs/importer"
+	chunk "github.com/jbenet/go-ipfs/importer/chunk"
+	. "github.com/jbenet/go-ipfs/merkledag"
+	"github.com/jbenet/go-ipfs/routing/mock"
+	uio "github.com/jbenet/go-ipfs/unixfs/io"
 	u "github.com/jbenet/go-ipfs/util"
 )
 
@@ -56,3 +67,84 @@ func TestNode(t *testing.T) {
 	printn("boop", n2)
 	printn("beep boop", n3)
 }
+
+func makeTestDag(t *testing.T) *Node {
+	read := io.LimitReader(u.NewTimeSeededRand(), 1024*32)
+	spl := &chunk.SizeSplitter{512}
+	root, err := imp.NewDagFromReaderWithSplitter(read, spl)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return root
+}
+
+func TestBatchFetch(t *testing.T) {
+	net := tn.VirtualNetwork()
+	rs := mock.VirtualRoutingServer()
+	sg := bs.NewSessionGenerator(net, rs)
+
+	instances := sg.Instances(5)
+
+	var servs []*bserv.BlockService
+	var dagservs []DAGService
+	for _, i := range instances {
+		bsi, err := bserv.New(i.Blockstore, i.Exchange)
+		if err != nil {
+			t.Fatal(err)
+		}
+		servs = append(servs, bsi)
+		dagservs = append(dagservs, NewDAGService(bsi))
+	}
+	t.Log("finished setup.")
+
+	root := makeTestDag(t)
+	read, err := uio.NewDagReader(root, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	expected, err := ioutil.ReadAll(read)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = dagservs[0].AddRecursive(root)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	t.Log("Added file to first node.")
+
+	k, err := root.Key()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	done := make(chan struct{})
+	for i := 1; i < len(dagservs); i++ {
+		go func(i int) {
+			first, err := dagservs[i].Get(k)
+			if err != nil {
+				t.Fatal(err)
+			}
+			fmt.Println("Got first node back.")
+
+			read, err := uio.NewDagReader(first, dagservs[i])
+			if err != nil {
+				t.Fatal(err)
+			}
+			datagot, err := ioutil.ReadAll(read)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			if !bytes.Equal(datagot, expected) {
+				t.Fatal("Got bad data back!")
+			}
+			done <- struct{}{}
+		}(i)
+	}
+
+	for i := 1; i < len(dagservs); i++ {
+		<-done
+	}
+}