func (cfg *BuildCfg) fillDefaults() error {
	if cfg.Repo != nil && cfg.NilRepo {
		return errors.New("cannot set a repo and specify nilrepo at the same time")
	}

	if cfg.Repo == nil {
		var d ds.Datastore
		d = ds.NewMapDatastore()
		if cfg.NilRepo {
			d = ds.NewNullDatastore()
		}
		r, err := defaultRepo(dsync.MutexWrap(d))
		if err != nil {
			return err
		}
		cfg.Repo = r
	}

	if cfg.Routing == nil {
		cfg.Routing = DHTOption
	}

	if cfg.Host == nil {
		cfg.Host = DefaultHostOption
	}

	return nil
}

func TestDuplicateSemantics(t *testing.T) {
	ctx := context.Background()
	dstore := dssync.MutexWrap(ds.NewMapDatastore())
	bstore := blockstore.NewBlockstore(dstore)
	bserv := bs.New(bstore, offline.Exchange(bstore))

	dserv := mdag.NewDAGService(bserv)

	// TODO does pinner need to share datastore with blockservice?
	p := NewPinner(dstore, dserv)

	a, _ := randNode()
	_, err := dserv.Add(a)
	if err != nil {
		t.Fatal(err)
	}

	// pin is recursively
	err = p.Pin(ctx, a, true)
	if err != nil {
		t.Fatal(err)
	}

	// pinning directly should fail
	err = p.Pin(ctx, a, false)
	if err == nil {
		t.Fatal("expected direct pin to fail")
	}

	// pinning recursively again should succeed
	err = p.Pin(ctx, a, true)
	if err != nil {
		t.Fatal(err)
	}
}

func getMockDagServ(t testing.TB) mdag.DAGService {
	dstore := ds.NewMapDatastore()
	tsds := sync.MutexWrap(dstore)
	bstore := blockstore.NewBlockstore(tsds)
	bserv := bs.New(bstore, offline.Exchange(bstore))
	return mdag.NewDAGService(bserv)
}

func TestPinRecursiveFail(t *testing.T) {
	ctx := context.Background()
	dstore := dssync.MutexWrap(ds.NewMapDatastore())
	bstore := blockstore.NewBlockstore(dstore)
	bserv := bs.New(bstore, offline.Exchange(bstore))
	dserv := mdag.NewDAGService(bserv)

	p := NewPinner(dstore, dserv)

	a, _ := randNode()
	b, _ := randNode()
	err := a.AddNodeLinkClean("child", b)
	if err != nil {
		t.Fatal(err)
	}

	// NOTE: This isnt a time based test, we expect the pin to fail
	mctx, _ := context.WithTimeout(ctx, time.Millisecond)
	err = p.Pin(mctx, a, true)
	if err == nil {
		t.Fatal("should have failed to pin here")
	}

	_, err = dserv.Add(b)
	if err != nil {
		t.Fatal(err)
	}

	// this one is time based... but shouldnt cause any issues
	mctx, _ = context.WithTimeout(ctx, time.Second)
	err = p.Pin(mctx, a, true)
	if err != nil {
		t.Fatal(err)
	}
}

func TestRoutingResolve(t *testing.T) {
	d := mockrouting.NewServer().Client(testutil.RandIdentityOrFatal(t))
	dstore := ds.NewMapDatastore()

	resolver := NewRoutingResolver(d, 0)
	publisher := NewRoutingPublisher(d, dstore)

	privk, pubk, err := testutil.RandTestKeyPair(512)
	if err != nil {
		t.Fatal(err)
	}

	h := path.FromString("/ipfs/QmZULkCELmmk5XNfCgTnCyFgAVxBRBXyDHGGMVoLFLiXEN")
	err = publisher.Publish(context.Background(), privk, h)
	if err != nil {
		t.Fatal(err)
	}

	pubkb, err := pubk.Bytes()
	if err != nil {
		t.Fatal(err)
	}

	pkhash := u.Hash(pubkb)
	res, err := resolver.Resolve(context.Background(), key.Key(pkhash).Pretty())
	if err != nil {
		t.Fatal(err)
	}

	if res != h {
		t.Fatal("Got back incorrect value.")
	}
}

func getMockDagServAndBstore(t testing.TB) (mdag.DAGService, blockstore.GCBlockstore) {
	dstore := ds.NewMapDatastore()
	tsds := sync.MutexWrap(dstore)
	bstore := blockstore.NewBlockstore(tsds)
	bserv := bs.New(bstore, offline.Exchange(bstore))
	dserv := mdag.NewDAGService(bserv)
	return dserv, bstore
}

// NewPeerstore creates a threadsafe collection of peers.
func NewPeerstore() Peerstore {
	return &peerstore{
		keybook:     *newKeybook(),
		metrics:     *(NewMetrics()).(*metrics),
		AddrManager: AddrManager{},
		ds:          dssync.MutexWrap(ds.NewMapDatastore()),
	}
}

func TestReturnsErrorWhenSizeNegative(t *testing.T) {
	bs := NewBlockstore(syncds.MutexWrap(ds.NewMapDatastore()))
	_, err := WriteCached(bs, -1)
	if err != nil {
		return
	}
	t.Fail()
}

func (pn *peernet) Adapter(p testutil.Identity) bsnet.BitSwapNetwork {
	client, err := pn.Mocknet.AddPeer(p.PrivateKey(), p.Address())
	if err != nil {
		panic(err.Error())
	}
	routing := pn.routingserver.ClientWithDatastore(context.TODO(), p, ds.NewMapDatastore())
	return bsnet.NewFromIpfsHost(client, routing)
}

func newEngine(ctx context.Context, idStr string) peerAndEngine {
	return peerAndEngine{
		Peer: peer.ID(idStr),
		//Strategy: New(true),
		Engine: NewEngine(ctx,
			blockstore.NewBlockstore(dssync.MutexWrap(ds.NewMapDatastore()))),
	}
}

func TestGetWhenKeyNotPresent(t *testing.T) {
	bs := NewBlockstore(ds_sync.MutexWrap(ds.NewMapDatastore()))
	_, err := bs.Get(key.Key("not present"))

	if err != nil {
		t.Log("As expected, block is not present")
		return
	}
	t.Fail()
}

func getDagservAndPinner(t *testing.T) dagservAndPinner {
	db := dssync.MutexWrap(ds.NewMapDatastore())
	bs := bstore.NewBlockstore(db)
	blockserv := bserv.New(bs, offline.Exchange(bs))
	dserv := NewDAGService(blockserv)
	mpin := pin.NewPinner(db, dserv)
	return dagservAndPinner{
		ds: dserv,
		mp: mpin,
	}
}

func TestValueTypeMismatch(t *testing.T) {
	block := blocks.NewBlock([]byte("some data"))

	datastore := ds.NewMapDatastore()
	k := BlockPrefix.Child(block.Key().DsKey())
	datastore.Put(k, "data that isn't a block!")

	blockstore := NewBlockstore(ds_sync.MutexWrap(datastore))

	_, err := blockstore.Get(block.Key())
	if err != ValueTypeMismatch {
		t.Fatal(err)
	}
}

func setupDHT(ctx context.Context, t *testing.T) *IpfsDHT {
	h := netutil.GenHostSwarm(t, ctx)

	dss := dssync.MutexWrap(ds.NewMapDatastore())
	d := NewDHT(ctx, h, dss)

	d.Validator["v"] = &record.ValidChecker{
		Func: func(key.Key, []byte) error {
			return nil
		},
		Sign: false,
	}
	return d
}

func TestFlush(t *testing.T) {
	dstore := dssync.MutexWrap(ds.NewMapDatastore())
	bstore := blockstore.NewBlockstore(dstore)
	bserv := bs.New(bstore, offline.Exchange(bstore))

	dserv := mdag.NewDAGService(bserv)
	p := NewPinner(dstore, dserv)
	_, k := randNode()

	p.PinWithMode(k, Recursive)
	if err := p.Flush(); err != nil {
		t.Fatal(err)
	}
	assertPinned(t, p, k, "expected key to still be pinned")
}

func TestElideDuplicateWrite(t *testing.T) {
	cd := &callbackDatastore{f: func() {}, ds: ds.NewMapDatastore()}
	bs := NewBlockstore(syncds.MutexWrap(cd))
	cachedbs, err := WriteCached(bs, 1)
	if err != nil {
		t.Fatal(err)
	}

	b1 := blocks.NewBlock([]byte("foo"))

	cachedbs.Put(b1)
	cd.SetFunc(func() {
		t.Fatal("write hit the datastore")
	})
	cachedbs.Put(b1)
}

func TestPutThenGetBlock(t *testing.T) {
	bs := NewBlockstore(ds_sync.MutexWrap(ds.NewMapDatastore()))
	block := blocks.NewBlock([]byte("some data"))

	err := bs.Put(block)
	if err != nil {
		t.Fatal(err)
	}

	blockFromBlockstore, err := bs.Get(block.Key())
	if err != nil {
		t.Fatal(err)
	}
	if !bytes.Equal(block.Data(), blockFromBlockstore.Data()) {
		t.Fail()
	}
}

func TestOutboxClosedWhenEngineClosed(t *testing.T) {
	t.SkipNow() // TODO implement *Engine.Close
	e := NewEngine(context.Background(), blockstore.NewBlockstore(dssync.MutexWrap(ds.NewMapDatastore())))
	var wg sync.WaitGroup
	wg.Add(1)
	go func() {
		for nextEnvelope := range e.Outbox() {
			<-nextEnvelope
		}
		wg.Done()
	}()
	// e.Close()
	wg.Wait()
	if _, ok := <-e.Outbox(); ok {
		t.Fatal("channel should be closed")
	}
}

func newBlockStoreWithKeys(t *testing.T, d ds.Datastore, N int) (Blockstore, []key.Key) {
	if d == nil {
		d = ds.NewMapDatastore()
	}
	bs := NewBlockstore(ds_sync.MutexWrap(d))

	keys := make([]key.Key, N)
	for i := 0; i < N; i++ {
		block := blocks.NewBlock([]byte(fmt.Sprintf("some data %d", i)))
		err := bs.Put(block)
		if err != nil {
			t.Fatal(err)
		}
		keys[i] = block.Key()
	}
	return bs, keys
}

func TestPartnerWantsThenCancels(t *testing.T) {
	numRounds := 10
	if testing.Short() {
		numRounds = 1
	}
	alphabet := strings.Split("abcdefghijklmnopqrstuvwxyz", "")
	vowels := strings.Split("aeiou", "")

	type testCase [][]string
	testcases := []testCase{
		{
			alphabet, vowels,
		},
		{
			alphabet, stringsComplement(alphabet, vowels),
		},
	}

	bs := blockstore.NewBlockstore(dssync.MutexWrap(ds.NewMapDatastore()))
	for _, letter := range alphabet {
		block := blocks.NewBlock([]byte(letter))
		if err := bs.Put(block); err != nil {
			t.Fatal(err)
		}
	}

	for i := 0; i < numRounds; i++ {
		for _, testcase := range testcases {
			set := testcase[0]
			cancels := testcase[1]
			keeps := stringsComplement(set, cancels)

			e := NewEngine(context.Background(), bs)
			partner := testutil.RandPeerIDFatal(t)

			partnerWants(e, set, partner)
			partnerCancels(e, cancels, partner)
			if err := checkHandledInOrder(t, e, keeps); err != nil {
				t.Logf("run #%d of %d", i, numRounds)
				t.Fatal(err)
			}
		}
	}
}