Add dhash test

Author: ischasny

store/dhash/dhash_test.go

@@ -0,0 +1,72 @@
+package dhash_test
+
+import (
+	"bytes"
+	"crypto/sha256"
+	"math/rand"
+	"testing"
+
+	"github.com/ipni/go-indexer-core/store/dhash"
+	"github.com/ipni/go-indexer-core/store/test"
+	"github.com/multiformats/go-multihash"
+	"github.com/stretchr/testify/require"
+)
+
+func TestEncryptSameValueWithTheSameMultihashShouldProduceTheSameOutput(t *testing.T) {
+	rng := rand.New(rand.NewSource(1413))
+	payload := make([]byte, 256)
+	_, err := rng.Read(payload)
+	if err != nil {
+		panic(err)
+	}
+	passphrase := make([]byte, 32)
+	_, err = rng.Read(passphrase)
+	require.NoError(t, err)
+
+	nonce1, encrypted1, err := dhash.EncryptAES(payload, passphrase)
+	require.NoError(t, err)
+
+	nonce2, encrypted2, err := dhash.EncryptAES(payload, passphrase)
+	require.NoError(t, err)
+
+	require.True(t, bytes.Equal(nonce1, nonce2))
+	require.True(t, bytes.Equal(encrypted1, encrypted2))
+}
+
+func TestCanDecryptEncryptedValue(t *testing.T) {
+	rng := rand.New(rand.NewSource(1413))
+	payload := make([]byte, 256)
+	_, err := rng.Read(payload)
+	if err != nil {
+		panic(err)
+	}
+	passphrase := make([]byte, 32)
+	_, err = rng.Read(passphrase)
+	require.NoError(t, err)
+
+	nonce, encrypted, err := dhash.EncryptAES(payload, passphrase)
+	require.NoError(t, err)
+
+	decrypted, err := dhash.DecryptAES(nonce, encrypted, passphrase)
+	require.NoError(t, err)
+
+	require.True(t, bytes.Equal(payload, decrypted))
+}
+
+func TestSecondMultihash(t *testing.T) {
+	secondHashPrefix := []byte("CR_DOUBLEHASH\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00")
+
+	mh := test.RandomMultihashes(1)[0]
+	smh, err := dhash.SecondMultihash(mh)
+	require.NoError(t, err)
+
+	h := sha256.New()
+	h.Write(append(secondHashPrefix, mh...))
+	digest := h.Sum(nil)
+
+	decoded, err := multihash.Decode(smh)
+	require.NoError(t, err)
+
+	require.Equal(t, uint64(multihash.DBL_SHA2_256), decoded.Code)
+	require.Equal(t, digest, decoded.Digest)
+}