add tests

Signed-off-by: bytemare <[email protected]>

internal/client.go

@@ -9,17 +9,11 @@
 package internal
 
 import (
-	"errors"
 	"slices"
 
 	group "github.com/bytemare/crypto"
 )
 
-var (
-	errBatchNoElements    = errors.New("no evaluated elements provided to Finalize()")
-	errBatchDifferentSize = errors.New("number of evaluations is different thant number of previously blinded inputs")
-)
-
 // A Client holds the core functionalities for all OPRF, TOPRF, VOPRF, and POPRF.
 type Client struct {
 	// Core abstracts configuration dependent operations.
@@ -106,14 +100,6 @@ func (c *Client) Finalize(index int, evaluated *group.Element, info ...byte) []b
 // FinalizeBatch unblinds the evaluated elements and returns the corresponding protocol outputs. The optional info
 // argument must only be provided when using the POPRF mode.
 func (c *Client) FinalizeBatch(evaluated []*group.Element, info ...byte) ([][]byte, error) {
-	if len(evaluated) == 0 {
-		return nil, errBatchNoElements
-	}
-
-	if len(evaluated) != c.Size() {
-		return nil, errBatchDifferentSize
-	}
-
 	out := make([][]byte, len(evaluated))
 
 	for i, e := range evaluated {

internal/nizk.go

@@ -19,7 +19,7 @@ const (
 	dstChallenge = "Challenge"
 )
 
-var errProofFailed = errors.New("proof fails")
+var errProofFailed = errors.New("invalid proof")
 
 // Verifiable enables VOPRF and POPRF functions over OPRF operations.
 type Verifiable struct {

oprf.go

@@ -12,6 +12,8 @@
 package voprf
 
 import (
+	"errors"
+
 	group "github.com/bytemare/crypto"
 
 	"github.com/bytemare/voprf/internal"
@@ -40,6 +42,11 @@ const (
 	Secp256k1 = Ciphersuite(group.Secp256k1)
 )
 
+var (
+	errBatchNoElements    = errors.New("no evaluated elements provided to Finalize()")
+	errBatchDifferentSize = errors.New("number of evaluations is different thant number of previously blinded inputs")
+)
+
 // FromGroup returns a Ciphersuite given a Group.
 func FromGroup(g group.Group) Ciphersuite {
 	return Ciphersuite(g)
@@ -112,6 +119,14 @@ func (c *Client) Finalize(evaluated *group.Element) []byte {
 
 // FinalizeBatch unblinds the evaluated elements and returns the corresponding protocol outputs.
 func (c *Client) FinalizeBatch(evaluated []*group.Element) ([][]byte, error) {
+	if len(evaluated) == 0 {
+		return nil, errBatchNoElements
+	}
+
+	if len(evaluated) != c.Size() {
+		return nil, errBatchDifferentSize
+	}
+
 	return c.Client.FinalizeBatch(evaluated)
 }
 

tests/encoding_test.go

@@ -10,29 +10,25 @@ package voprf_test
 
 import (
 	"bytes"
-	"strings"
 	"testing"
 
 	"github.com/bytemare/voprf/voprf"
 )
 
 func Test_DecodeElement(t *testing.T) {
 	testAll(t, func(c *configuration) {
-		bad := getBadElement(t, c)
-
-		if _, err := c.ciphersuite.DecodeElement(bad); err == nil ||
-			!strings.Contains(err.Error(), "element Decode: ") {
-			t.Errorf("expected error, got %v", err)
+		element := c.group.NewElement().Base().Multiply(c.group.NewScalar().Random()).Encode()
+		if _, err := c.ciphersuite.DecodeElement(element); err != nil {
+			t.Errorf("unexpected error, got %v", err)
 		}
 	})
 }
 
 func Test_DecodeScalar(t *testing.T) {
 	testAll(t, func(c *configuration) {
-		bad := getBadScalar(t, c)
-
-		if _, err := c.ciphersuite.DecodeScalar(bad); err == nil || !strings.Contains(err.Error(), "scalar Decode: ") {
-			t.Errorf("expected error, got %v", err)
+		scalar := c.group.NewScalar().Random().Encode()
+		if _, err := c.ciphersuite.DecodeScalar(scalar); err != nil {
+			t.Errorf("unexpected error, got %v", err)
 		}
 	})
 }