chore: Java interop PR

common/common_test.go

@@ -0,0 +1,103 @@
+package common_test
+
+import (
+	"bytes"
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+	"io"
+	"os"
+	"testing"
+
+	"github.com/crate-crypto/go-ipa/bandersnatch/fr"
+	"github.com/crate-crypto/go-ipa/common"
+	"github.com/crate-crypto/go-ipa/ipa"
+)
+
+func TestJavaRegressionOneEndian(t *testing.T) {
+	hexStr := "f6e31f7a565a390b48fdd24569ac10d43562d19de37ea951c7f9f250a339d059"
+	byteArray := hexStrToBytes(hexStr)
+	_scalar, err := common.ReadScalar(bytes.NewReader(byteArray))
+
+	if err == nil {
+		t.Fatalf("expected an error because the scalar is too large")
+	}
+	_ = _scalar
+}
+func TestJavaRegressionOtherEndian(t *testing.T) {
+	hexStr := "f6e31f7a565a390b48fdd24569ac10d43562d19de37ea951c7f9f250a339d059"
+	byteArray := hexStrToBytes(hexStr)
+	reverse(byteArray)
+	_scalar, err := common.ReadScalar(bytes.NewReader(byteArray))
+	if err == nil {
+		t.Fatalf("expected an error because the scalar is too large, even though we changed the endian")
+	}
+	_ = _scalar
+}
+
+type AutoGenerated []struct {
+	Frs      []string `json:"frs"`
+	Expected string   `json:"expected"`
+}
+
+// genesis_lvl1_commitments.json was generated by serializing the scalars -1, -2,...,-256
+// The scalars are encoded in big-endian format for now, so that the java code does not need
+// much change.
+func TestNewGenesisLvl1Commit(t *testing.T) {
+	// Open the JSON file
+	jsonFile, err := os.Open("../genesis_lvl1_commits.json")
+	if err != nil {
+		t.Fail()
+		fmt.Println(err)
+	}
+	defer jsonFile.Close()
+
+	// Read the opened jsonFile as a byte array.
+	byteArray, _ := io.ReadAll(jsonFile)
+
+	// We initialize our struct
+	var testData AutoGenerated
+	json.Unmarshal(byteArray, &testData)
+
+	ipaConf, err := ipa.NewIPASettings()
+	if err != nil {
+		t.Fatalf("creating IPA settings: %s", err)
+	}
+
+	scalars := make([]fr.Element, common.VectorLength)
+
+	serializedScalars := testData[0].Frs
+	for i := 0; i < common.VectorLength; i++ {
+		scalarBytes, err := hex.DecodeString(serializedScalars[i])
+		if err != nil {
+			t.Fatalf("decoding scalar bytes: %s", err)
+		}
+		reverse(scalarBytes) // Reverse bytes so we use LE
+		scalars_i, err := common.ReadScalar(bytes.NewReader(scalarBytes))
+		if err != nil {
+			t.Fatalf("reading scalar: %s", err)
+		}
+		scalars[i] = *scalars_i
+	}
+	comm := ipaConf.Commit(scalars)
+	commBytes := comm.Bytes()
+	commHexStr := hex.EncodeToString(commBytes[:])
+	if commHexStr != testData[0].Expected {
+		t.Fatalf("expected %s, got %s", testData[0].Expected, commHexStr)
+	}
+}
+
+func reverse(data []byte) {
+	for i, j := 0, len(data)-1; i < j; i, j = i+1, j-1 {
+		data[i], data[j] = data[j], data[i]
+	}
+}
+
+func hexStrToBytes(numStr string) []byte {
+
+	byteArray, err := hex.DecodeString(numStr)
+	if err != nil {
+		panic(err)
+	}
+	return byteArray
+}