test fixes

op-node/rollup/derive/channel.go

@@ -161,11 +161,13 @@ func BatchReader(r io.Reader) (func() (*BatchData, error), error) {
 		return nil, err
 	}
 
-	var reader func(io.Reader) (io.Reader, error)
+	var zr io.Reader
 	// For zlib, the last 4 bits must be either 8 or 15 (both are reserved value)
 	if compressionType[0]&0x0F == ZlibCM8 || compressionType[0]&0x0F == ZlibCM15 {
-		reader = func(r io.Reader) (io.Reader, error) {
-			return zlib.NewReader(r)
+		var err error
+		zr, err = zlib.NewReader(bufReader)
+		if err != nil {
+			return nil, err
 		}
 		// If the bits equal to 1, then it is a brotli reader
 	} else if compressionType[0] == ChannelVersionBrotli {
@@ -174,23 +176,17 @@ func BatchReader(r io.Reader) (func() (*BatchData, error), error) {
 		if err != nil {
 			return nil, err
 		}
-		reader = func(r io.Reader) (io.Reader, error) {
-			return brotli.NewReader(r), nil
-		}
+		zr = brotli.NewReader(bufReader)
 	} else {
 		return nil, fmt.Errorf("cannot distinguish the compression algo used given type byte %v", compressionType[0])
 	}
 
 	// Setup decompressor stage + RLP reader
-	zr, err := reader(bufReader)
-	if err != nil {
-		return nil, err
-	}
 	rlpReader := rlp.NewStream(zr, MaxRLPBytesPerChannel)
 	// Read each batch iteratively
 	return func() (*BatchData, error) {
 		var batchData BatchData
-		if err = rlpReader.Decode(&batchData); err != nil {
+		if err := rlpReader.Decode(&batchData); err != nil {
 			return nil, err
 		}
 		return &batchData, nil

op-node/rollup/derive/channel_test.go

@@ -10,7 +10,7 @@ import (
 	"github.com/DataDog/zstd"
 	"github.com/andybalholm/brotli"
 	"github.com/ethereum-optimism/optimism/op-service/eth"
-
+	"github.com/ethereum/go-ethereum/rlp"
 	"github.com/stretchr/testify/require"
 )
 
@@ -114,8 +114,11 @@ func TestBatchReader(t *testing.T) {
 	batchDataInput := NewBatchData(singularBatch)
 
 	encodedBatch := &bytes.Buffer{}
+	buf := &bytes.Buffer{}
 	// Get the encoded data of the batch data
-	batchDataInput.encodeTyped(encodedBatch)
+	batchDataInput.encodeTyped(buf)
+	err := rlp.Encode(encodedBatch, buf.Bytes())
+	require.NoError(t, err)
 
 	var testCases = []struct {
 		name string
@@ -125,6 +128,7 @@ func TestBatchReader(t *testing.T) {
 		algo: func(buf *bytes.Buffer) {
 			writer := zlib.NewWriter(buf)
 			writer.Write(encodedBatch.Bytes())
+			writer.Close()
 		},
 	},
 		{
@@ -133,12 +137,14 @@ func TestBatchReader(t *testing.T) {
 				buf.WriteByte(ChannelVersionBrotli)
 				writer := brotli.NewWriterLevel(buf, 10)
 				writer.Write(encodedBatch.Bytes())
+				writer.Close()
 			},
 		}, {
 			name: "zstd",
 			algo: func(buf *bytes.Buffer) {
 				writer := zstd.NewWriter(buf)
 				writer.Write(encodedBatch.Bytes())
+				writer.Close()
 			},
 		}}