truffle 2=>3

test/helpers/SafeMathMock.sol

@@ -0,0 +1,21 @@
+pragma solidity ^0.4.4;
+
+
+import '../../contracts/SafeMath.sol';
+
+
+contract SafeMathMock is SafeMath {
+  uint public result;
+
+  function multiply(uint a, uint b) {
+    result = safeMul(a, b);
+  }
+
+  function subtract(uint a, uint b) {
+    result = safeSub(a, b);
+  }
+
+  function add(uint a, uint b) {
+    result = safeAdd(a, b);
+  }
+}