From 6ca7a3ec210726385d03a51cc1b370a3dd58e0ab Mon Sep 17 00:00:00 2001
From: Jae Kwon <jae@tendermint.com>
Date: Sun, 19 Jul 2015 09:45:40 -0700
Subject: [PATCH] Fix Makefile build command; Define Signature interface

---
 Makefile             | 2 +-
 account/signature.go | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index b2e5709e..79ac2279 100644
--- a/Makefile
+++ b/Makefile
@@ -28,7 +28,7 @@ build_race:
 
 test: build
 	-rm -rf ~/.tendermint_test_bak
-	mv ~/.tendermint_test ~/.tendermint_test_bak
+	-mv ~/.tendermint_test ~/.tendermint_test_bak
 	go test github.com/tendermint/tendermint/...
 
 draw_deps:
diff --git a/account/signature.go b/account/signature.go
index ab4d1175..a858cb0f 100644
--- a/account/signature.go
+++ b/account/signature.go
@@ -9,6 +9,8 @@ import (
 
 // Signature is a part of Txs and consensus Votes.
 type Signature interface {
+	IsZero() bool
+	String() string
 }
 
 // Types of Signature implementations