feat: add scale codec tests to header (#28)

* feat: add codec tests

internal/block/header_test.go

@@ -0,0 +1,86 @@
+package block
+
+import (
+	"crypto/ed25519"
+	"crypto/rand"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/eigerco/strawberry/internal/crypto"
+	"github.com/eigerco/strawberry/internal/jamtime"
+	"github.com/eigerco/strawberry/pkg/serialization"
+	"github.com/eigerco/strawberry/pkg/serialization/codec"
+)
+
+func Test_HeaderEncodeDecode(t *testing.T) {
+	h := Header{
+		ParentHash:     randomHash(t),
+		PriorStateRoot: randomHash(t),
+		ExtrinsicHash:  randomHash(t),
+		TimeSlotIndex:  123,
+		EpochMarker: &EpochMarker{
+			Keys: [NumberOfValidators]crypto.BandersnatchPublicKey{
+				randomPublicKey(t),
+				randomPublicKey(t),
+			},
+			Entropy: randomHash(t),
+		},
+		WinningTicketsMarker: [jamtime.TimeslotsPerEpoch]*Ticket{{
+			Identifier: randomHash(t),
+			EntryIndex: 111,
+		}, {
+			Identifier: randomHash(t),
+			EntryIndex: 222,
+		}},
+		Verdicts: []crypto.Hash{
+			randomHash(t),
+			randomHash(t),
+		},
+		OffendersMarkers: []crypto.Ed25519PublicKey{
+			randomED25519PublicKey(t),
+		},
+		BlockAuthorIndex:   1,
+		VRFSignature:       randomSignature(t),
+		BlockSealSignature: randomSignature(t),
+	}
+	serializer := serialization.NewSerializer(&codec.SCALECodec{})
+	bb, err := serializer.Encode(h)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	h2 := Header{}
+	err = serializer.Decode(bb, &h2)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	assert.Equal(t, h, h2)
+}
+
+func randomHash(t *testing.T) crypto.Hash {
+	hash := make([]byte, crypto.HashSize)
+	_, err := rand.Read(hash)
+	require.NoError(t, err)
+	return crypto.Hash(hash)
+}
+func randomED25519PublicKey(t *testing.T) crypto.Ed25519PublicKey {
+	hash := make([]byte, ed25519.PublicKeySize)
+	_, err := rand.Read(hash)
+	require.NoError(t, err)
+	return hash
+}
+func randomPublicKey(t *testing.T) crypto.BandersnatchPublicKey {
+	hash := make([]byte, crypto.BandersnatchSize)
+	_, err := rand.Read(hash)
+	require.NoError(t, err)
+	return crypto.BandersnatchPublicKey(hash)
+}
+func randomSignature(t *testing.T) crypto.BandersnatchSignature {
+	hash := make([]byte, 96)
+	_, err := rand.Read(hash)
+	require.NoError(t, err)
+	return crypto.BandersnatchSignature(hash)
+}