Abstract TxProcessor from StateDB

- Abstract TxProcessor from StateDB
- Upgrade to last version of go-merkletree for the key-value DB usage

txprocessor/utils_test.go

@@ -0,0 +1,39 @@
+package txprocessor
+
+import (
+	"math/big"
+	"testing"
+
+	"github.com/iden3/go-iden3-crypto/babyjub"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestBJJCompressedTo256BigInt(t *testing.T) {
+	var pkComp babyjub.PublicKeyComp
+	r := BJJCompressedTo256BigInts(pkComp)
+	zero := big.NewInt(0)
+	for i := 0; i < 256; i++ {
+		assert.Equal(t, zero, r[i])
+	}
+
+	pkComp[0] = 3
+	r = BJJCompressedTo256BigInts(pkComp)
+	one := big.NewInt(1)
+	for i := 0; i < 256; i++ {
+		if i != 0 && i != 1 {
+			assert.Equal(t, zero, r[i])
+		} else {
+			assert.Equal(t, one, r[i])
+		}
+	}
+
+	pkComp[31] = 4
+	r = BJJCompressedTo256BigInts(pkComp)
+	for i := 0; i < 256; i++ {
+		if i != 0 && i != 1 && i != 250 {
+			assert.Equal(t, zero, r[i])
+		} else {
+			assert.Equal(t, one, r[i])
+		}
+	}
+}