merkledb -- add codec test and move helper (#1944)

Author: Dan Laine

x/merkledb/codec_test.go

@@ -12,54 +12,9 @@ import (
 	"github.com/stretchr/testify/require"
 
 	"github.com/ava-labs/avalanchego/ids"
-	"github.com/ava-labs/avalanchego/utils/hashing"
 	"github.com/ava-labs/avalanchego/utils/maybe"
 )
 
-// TODO add more codec tests
-
-func newRandomProofNode(r *rand.Rand) ProofNode {
-	key := make([]byte, r.Intn(32)) // #nosec G404
-	_, _ = r.Read(key)              // #nosec G404
-	serializedKey := newPath(key).Serialize()
-
-	val := make([]byte, r.Intn(64)) // #nosec G404
-	_, _ = r.Read(val)              // #nosec G404
-
-	children := map[byte]ids.ID{}
-	for j := 0; j < NodeBranchFactor; j++ {
-		if r.Float64() < 0.5 {
-			var childID ids.ID
-			_, _ = r.Read(childID[:]) // #nosec G404
-			children[byte(j)] = childID
-		}
-	}
-
-	hasValue := rand.Intn(2) == 1 // #nosec G404
-	var valueOrHash maybe.Maybe[[]byte]
-	if hasValue {
-		// use the hash instead when length is greater than the hash length
-		if len(val) >= HashLength {
-			val = hashing.ComputeHash256(val)
-		} else if len(val) == 0 {
-			// We do this because when we encode a value of []byte{} we will later
-			// decode it as nil.
-			// Doing this prevents inconsistency when comparing the encoded and
-			// decoded values.
-			// Calling nilEmptySlices doesn't set this because it is a private
-			// variable on the struct
-			val = nil
-		}
-		valueOrHash = maybe.Some(val)
-	}
-
-	return ProofNode{
-		KeyPath:     serializedKey,
-		ValueOrHash: valueOrHash,
-		Children:    children,
-	}
-}
-
 func FuzzCodecBool(f *testing.F) {
 	f.Fuzz(
 		func(
@@ -224,7 +179,7 @@ func FuzzCodecDBNodeDeterministic(f *testing.F) {
 	)
 }
 
-func TestCodec_DecodeDBNode(t *testing.T) {
+func TestCodecDecodeDBNode(t *testing.T) {
 	require := require.New(t)
 
 	var (
@@ -260,3 +215,59 @@ func TestCodec_DecodeDBNode(t *testing.T) {
 	err = codec.decodeDBNode(proofBytesBuf.Bytes(), &parsedDBNode)
 	require.ErrorIs(err, errTooManyChildren)
 }
+
+// Ensure that encodeHashValues is deterministic
+func FuzzEncodeHashValues(f *testing.F) {
+	codec1 := newCodec()
+	codec2 := newCodec()
+
+	f.Fuzz(
+		func(
+			t *testing.T,
+			randSeed int,
+		) {
+			require := require.New(t)
+
+			// Create a random *hashValues
+			r := rand.New(rand.NewSource(int64(randSeed))) // #nosec G404
+
+			children := map[byte]child{}
+			numChildren := r.Intn(NodeBranchFactor) // #nosec G404
+			for i := 0; i < numChildren; i++ {
+				compressedPathLen := r.Intn(32) // #nosec G404
+				compressedPathBytes := make([]byte, compressedPathLen)
+				_, _ = r.Read(compressedPathBytes) // #nosec G404
+
+				children[byte(i)] = child{
+					compressedPath: newPath(compressedPathBytes),
+					id:             ids.GenerateTestID(),
+					hasValue:       r.Intn(2) == 1, // #nosec G404
+				}
+			}
+
+			hasValue := r.Intn(2) == 1 // #nosec G404
+			value := maybe.Nothing[[]byte]()
+			if hasValue {
+				valueBytes := make([]byte, r.Intn(64)) // #nosec G404
+				_, _ = r.Read(valueBytes)              // #nosec G404
+				value = maybe.Some(valueBytes)
+			}
+
+			key := make([]byte, r.Intn(32)) // #nosec G404
+			_, _ = r.Read(key)              // #nosec G404
+
+			hv := &hashValues{
+				Children: children,
+				Value:    value,
+				Key:      newPath(key).Serialize(),
+			}
+
+			// Serialize the *hashValues with both codecs
+			hvBytes1 := codec1.encodeHashValues(hv)
+			hvBytes2 := codec2.encodeHashValues(hv)
+
+			// Make sure they're the same
+			require.Equal(hvBytes1, hvBytes2)
+		},
+	)
+}

x/merkledb/proof_test.go

@@ -43,6 +43,46 @@ func writeBasicBatch(t *testing.T, db *merkleDB) {
 	require.NoError(batch.Write())
 }
 
+func newRandomProofNode(r *rand.Rand) ProofNode {
+	key := make([]byte, r.Intn(32)) // #nosec G404
+	_, _ = r.Read(key)              // #nosec G404
+	serializedKey := newPath(key).Serialize()
+
+	val := make([]byte, r.Intn(64)) // #nosec G404
+	_, _ = r.Read(val)              // #nosec G404
+
+	children := map[byte]ids.ID{}
+	for j := 0; j < NodeBranchFactor; j++ {
+		if r.Float64() < 0.5 {
+			var childID ids.ID
+			_, _ = r.Read(childID[:]) // #nosec G404
+			children[byte(j)] = childID
+		}
+	}
+
+	hasValue := rand.Intn(2) == 1 // #nosec G404
+	var valueOrHash maybe.Maybe[[]byte]
+	if hasValue {
+		// use the hash instead when length is greater than the hash length
+		if len(val) >= HashLength {
+			val = hashing.ComputeHash256(val)
+		} else if len(val) == 0 {
+			// We do this because when we encode a value of []byte{} we will later
+			// decode it as nil.
+			// Doing this prevents inconsistency when comparing the encoded and
+			// decoded values.
+			val = nil
+		}
+		valueOrHash = maybe.Some(val)
+	}
+
+	return ProofNode{
+		KeyPath:     serializedKey,
+		ValueOrHash: valueOrHash,
+		Children:    children,
+	}
+}
+
 func Test_Proof_Empty(t *testing.T) {
 	proof := &Proof{}
 	err := proof.Verify(context.Background(), ids.Empty)