proof: unit test CommitmentProofs en-/decoder

This commit adds a unit test that does a roundtrip for the
`CommitmentProofsEncoder` and `CommitmentProofsDecoder`to check if the
random commitment proofs come out at the other end unscathed.

Author: gijswijs

proof/encoding_test.go

@@ -0,0 +1,95 @@
+package proof
+
+import (
+	"bytes"
+	"reflect"
+	"testing"
+
+	"github.com/lightninglabs/taproot-assets/asset"
+	"github.com/lightninglabs/taproot-assets/commitment"
+	"github.com/lightninglabs/taproot-assets/internal/test"
+	"github.com/stretchr/testify/require"
+)
+
+func TestCommitmentProofsDecoderRoundTrip(t *testing.T) {
+	t.Parallel()
+
+	testBlocks := readTestData(t)
+	oddTxBlock := testBlocks[0]
+
+	numProofs := 4
+	proofs := make(map[asset.SerializedKey]commitment.Proof, numProofs)
+	for range numProofs {
+		genesis := asset.RandGenesis(t, asset.Collectible)
+		scriptKey := test.RandPubKey(t)
+		randProof := RandProof(t, genesis, scriptKey, oddTxBlock, 0, 1)
+		randCommitmentProof := randProof.InclusionProof.CommitmentProof
+		serializedKey := asset.SerializedKey(
+			test.RandPubKey(t).SerializeCompressed(),
+		)
+		proofs[serializedKey] = randCommitmentProof.Proof
+	}
+
+	var buf [8]byte
+
+	// Helper function to encode a map of commitment proofs.
+	encodeProofs := func(proofs map[asset.SerializedKey]commitment.Proof,
+	) []byte {
+
+		var b bytes.Buffer
+		err := CommitmentProofsEncoder(&b, &proofs, &buf)
+		require.NoError(t, err)
+		return b.Bytes()
+	}
+
+	// Helper function to decode a map of commitment proofs.
+	decodeProofs := func(encoded []byte,
+	) map[asset.SerializedKey]commitment.Proof {
+
+		var decodedProofs map[asset.SerializedKey]commitment.Proof
+		err := CommitmentProofsDecoder(
+			bytes.NewReader(encoded), &decodedProofs, &buf,
+			uint64(len(encoded)),
+		)
+		require.NoError(t, err)
+		return decodedProofs
+	}
+
+	// Test case: round trip encoding and decoding.
+	t.Run(
+		"encode and decode map of 4 random commitment proofs",
+		func(t *testing.T,
+		) {
+
+			// Encode the proofs.
+			encoded := encodeProofs(proofs)
+
+			// Decode the proofs.
+			decodedProofs := decodeProofs(encoded)
+
+			// Assert the decoded proofs match the original.
+			require.True(t, reflect.DeepEqual(
+				proofs, decodedProofs,
+			))
+		})
+
+	// Test case: empty map.
+	t.Run(
+		"encode and decode empty map of commitment proofs",
+		func(t *testing.T,
+		) {
+			// Create an empty map of commitment emptyMap.
+			emptyMap := map[asset.SerializedKey]commitment.Proof{}
+
+			// Encode the proofs.
+			encoded := encodeProofs(emptyMap)
+
+			// Decode the proofs.
+			decodedMap := decodeProofs(encoded)
+
+			// Assert the decoded proofs match the original.
+			require.True(t, reflect.DeepEqual(
+				emptyMap, decodedMap,
+			))
+		})
+}