Add tests for hasher

* Part of #177

merkletree/hasher/hasher_test.go

@@ -0,0 +1,55 @@
+package hasher
+
+import (
+	"encoding/hex"
+	"testing"
+)
+
+// h2h converts a hex string into its Hash object.
+func h2h(h string) Hash {
+	b, err := hex.DecodeString(h)
+	if err != nil {
+		panic("invalid hex string")
+	}
+	var ret Hash
+	copy(ret[:], b)
+	return ret
+}
+
+// s2h converts a byte slice into its Hash object.
+func s2h(s []byte) Hash {
+	var ret Hash
+	copy(ret[:], s)
+	return ret
+}
+
+func TestHashLeafVectors(t *testing.T) {
+	for _, tc := range []struct {
+		treeNonce []byte // treeNonce is treeID in KT, it should be a 8-byte slice
+		index     []byte
+		depth     uint32
+		leaf      []byte
+		want      Hash
+	}{
+		{treeNonce: make([]byte, 8), index: []byte("foo"), depth: 128, leaf: []byte("leaf"), want: h2h("d7e63cd03f40c88dcddd11cd33d060ba555adf5a792846fb47fea12d95d3501c")},
+	} {
+		if got, want := s2h(Default.HashLeaf(tc.treeNonce, tc.index, tc.depth, tc.leaf)), tc.want; got != want {
+			t.Errorf("HashLeaf(%v, %s, %v, %s): %x, want %x", tc.treeNonce, tc.index, tc.depth, tc.leaf, got, want)
+		}
+	}
+}
+
+func TestHashEmptyVectors(t *testing.T) {
+	for _, tc := range []struct {
+		treeNonce []byte // treeNonce is treeID in KT, it should be a 8-byte slice
+		index     []byte
+		depth     uint32
+		want      Hash
+	}{
+		{treeNonce: make([]byte, 8), index: []byte("foo"), depth: 128, want: h2h("ee50dbada0aeb067724550e453101b802034a277bc0565d751c22ee1dce4998f")},
+	} {
+		if got, want := s2h(Default.HashEmpty(tc.treeNonce, tc.index, tc.depth)), tc.want; got != want {
+			t.Errorf("HashLeaf(%v, %s, %v): %x, want %x", tc.treeNonce, tc.index, tc.depth, got, want)
+		}
+	}
+}