enhancement/rln-hash-test (#3)

* started hash test

* playing around

* fix

* fix

* fix

rln/rln.go

@@ -66,12 +66,16 @@ func (r *RLN) GenerateKey() (*KeyPair, error) {
 
 // Hash hashes a given input using the underlying function.
 func (r *RLN) Hash(input []byte) ([]byte, error) {
-	size := int(unsafe.Sizeof(C.Buffer{}))
-	in := (*C.Buffer)(C.malloc(C.size_t(size)))
-	*in = toBuffer(input)
 
-	out := (*C.Buffer)(C.malloc(C.size_t(size)))
-	if !bool(C.hash(r.ptr, in, in.len, out)) {
+	buf := toBuffer(input)
+	size := int(unsafe.Sizeof(buf))
+	in := (*C.Buffer)(C.malloc(C.size_t(size)))
+	*in = buf
+
+	var output []byte
+	out := toBuffer(output)
+
+	if !bool(C.hash(r.ptr, in, 1, &out)) {
 		return nil, errors.New("failed to hash")
 	}
 

rln/rln_test.go

@@ -1,6 +1,7 @@
 package rln_test
 
 import (
+	"encoding/hex"
 	"io/ioutil"
 	"reflect"
 	"testing"
@@ -44,3 +45,40 @@ func TestGenerateKey(t *testing.T) {
 		t.Fatal("k.Commitment was empty")
 	}
 }
+
+func TestRLN_Hash(t *testing.T) {
+	// This test is based on tests from:
+	// https://github.com/status-im/nim-waku/blob/b7998de09d1ef04599a699938da69aecfa63cc6f/tests/v2/test_waku_rln_relay.nim#L527
+
+	params, err := ioutil.ReadFile("./testdata/parameters.key")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	r, err := rln.New(32, params)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	input := byteArray(32, 1)
+
+	output, err := r.Hash(input)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	expected := "53a6338cdbf02f0563cec1898e354d0d272c8f98b606c538945c6f41ef101828"
+	if expected != hex.EncodeToString(output) {
+		t.Fatalf("value %x did not match expected %s", output, expected)
+	}
+}
+
+func byteArray(length int, value byte) []byte {
+	arr := make([]byte, length)
+
+	for i := 0; i < length; i++ {
+		arr[i] = value
+	}
+
+	return arr
+}