test: add basic dagreader test

License: MIT
Signed-off-by: Jakub Sztandera <kubuxu@protonmail.ch>

unixfs/io/dagserv_test.go

+package io
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"testing"
+
+	"github.com/ipfs/go-ipfs/blocks/blockstore"
+	bs "github.com/ipfs/go-ipfs/blockservice"
+	"github.com/ipfs/go-ipfs/exchange/offline"
+	imp "github.com/ipfs/go-ipfs/importer"
+	"github.com/ipfs/go-ipfs/importer/chunk"
+	mdag "github.com/ipfs/go-ipfs/merkledag"
+
+	ds "gx/ipfs/QmTxLSvdhwg68WJimdS6icLPhZi28aTp6b7uihC2Yb47Xk/go-datastore"
+	"gx/ipfs/QmTxLSvdhwg68WJimdS6icLPhZi28aTp6b7uihC2Yb47Xk/go-datastore/sync"
+	u "gx/ipfs/QmZNVWh8LLjAavuQ2JXuFmuYH3C11xo988vSgp7UQrTRj1/go-ipfs-util"
+	context "gx/ipfs/QmZy2y8t9zQH2a1b8q2ZSLKp17ATuJoCNxxyMFG5qFExpt/go-net/context"
+)
+
+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 sizeSplitterGen(size int64) chunk.SplitterGen {
+	return func(r io.Reader) chunk.Splitter {
+		return chunk.NewSizeSplitter(r, size)
+	}
+}
+
+func getNode(t testing.TB, dserv mdag.DAGService, data []byte) *mdag.Node {
+	in := bytes.NewReader(data)
+	node, err := imp.BuildTrickleDagFromReader(dserv, sizeSplitterGen(500)(in))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	return node
+}
+
+func getRandomNode(t testing.TB, dserv mdag.DAGService, size int64) ([]byte, *mdag.Node) {
+	in := io.LimitReader(u.NewTimeSeededRand(), size)
+	buf, err := ioutil.ReadAll(in)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	node := getNode(t, dserv, buf)
+	return buf, node
+}
+
+func arrComp(a, b []byte) error {
+	if len(a) != len(b) {
+		return fmt.Errorf("Arrays differ in length. %d != %d", len(a), len(b))
+	}
+	for i, v := range a {
+		if v != b[i] {
+			return fmt.Errorf("Arrays differ at index: %d", i)
+		}
+	}
+	return nil
+}
+
+func TestBasicRead(t *testing.T) {
+	dserv := getMockDagServ(t)
+	inbuf, node := getRandomNode(t, dserv, 1024)
+	ctx, closer := context.WithCancel(context.Background())
+	defer closer()
+
+	reader, err := NewDagReader(ctx, node, dserv)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	outbuf, err := ioutil.ReadAll(reader)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = arrComp(inbuf, outbuf)
+	if err != nil {
+		t.Fatal(err)
+	}
+}