From 4cf69d7cd34394fa7408bb5a6e152610a9daa81c Mon Sep 17 00:00:00 2001
From: Felix Lange <fjl@twurst.com>
Date: Wed, 29 Oct 2014 18:40:18 +0100
Subject: [PATCH] vm: fix basic VM tests

The tests now compile and won't panic for unexpected return values.

We need a recent-enough version of the mutan compiler because of
the new JUMPDEST requirements. Skip some tests if the installed mutan
version is too old. The debug VM test still fails, probably because
of an implementation bug.
---
 vm/vm_test.go | 54 +++++++++++++++++++++++++++++++++------------------
 1 file changed, 35 insertions(+), 19 deletions(-)

diff --git a/vm/vm_test.go b/vm/vm_test.go
index 84cca3a9d..8818cc8ec 100644
--- a/vm/vm_test.go
+++ b/vm/vm_test.go
@@ -14,22 +14,30 @@ import (
 	"github.com/ethereum/go-ethereum/ethstate"
 	"github.com/ethereum/go-ethereum/ethtrie"
 	"github.com/ethereum/go-ethereum/ethutil"
+	"github.com/obscuren/mutan"
 )
 
-type TestEnv struct {
+type TestEnv struct{}
+
+func (TestEnv) Origin() []byte        { return nil }
+func (TestEnv) BlockNumber() *big.Int { return nil }
+func (TestEnv) BlockHash() []byte     { return nil }
+func (TestEnv) PrevHash() []byte      { return nil }
+func (TestEnv) Coinbase() []byte      { return nil }
+func (TestEnv) Time() int64           { return 0 }
+func (TestEnv) GasLimit() *big.Int    { return nil }
+func (TestEnv) Difficulty() *big.Int  { return nil }
+func (TestEnv) Value() *big.Int       { return nil }
+func (TestEnv) AddLog(Log)            {}
+
+func (TestEnv) Transfer(from, to Account, amount *big.Int) error {
+	return nil
 }
 
-func (self TestEnv) Origin() []byte        { return nil }
-func (self TestEnv) BlockNumber() *big.Int { return nil }
-func (self TestEnv) BlockHash() []byte     { return nil }
-func (self TestEnv) PrevHash() []byte      { return nil }
-func (self TestEnv) Coinbase() []byte      { return nil }
-func (self TestEnv) Time() int64           { return 0 }
-func (self TestEnv) Difficulty() *big.Int  { return nil }
-func (self TestEnv) Value() *big.Int       { return nil }
-
 // This is likely to fail if anything ever gets looked up in the state trie :-)
-func (self TestEnv) State() *ethstate.State { return ethstate.New(ethtrie.New(nil, "")) }
+func (TestEnv) State() *ethstate.State {
+	return ethstate.New(ethtrie.New(nil, ""))
+}
 
 const mutcode = `
 var x = 0;
@@ -56,27 +64,35 @@ func setup(level ethlog.LogLevel, typ Type) (*Closure, VirtualMachine) {
 	return callerClosure, New(TestEnv{}, typ)
 }
 
+var big9 = ethutil.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000009")
+
 func TestDebugVm(t *testing.T) {
+	if mutan.Version < "0.6" {
+		t.Skip("skipping for mutan version", mutan.Version, " < 0.6")
+	}
+
 	closure, vm := setup(ethlog.DebugLevel, DebugVmTy)
 	ret, _, e := closure.Call(vm, nil)
 	if e != nil {
-		fmt.Println("error", e)
+		t.Fatalf("Call returned error: %v", e)
 	}
-
-	if ret[len(ret)-1] != 9 {
-		t.Errorf("Expected VM to return 9, got", ret, "instead.")
+	if !bytes.Equal(ret, big9) {
+		t.Errorf("Wrong return value '%x', want '%x'", ret, big9)
 	}
 }
 
 func TestVm(t *testing.T) {
+	if mutan.Version < "0.6" {
+		t.Skip("skipping for mutan version", mutan.Version, " < 0.6")
+	}
+
 	closure, vm := setup(ethlog.DebugLevel, StandardVmTy)
 	ret, _, e := closure.Call(vm, nil)
 	if e != nil {
-		fmt.Println("error", e)
+		t.Fatalf("Call returned error: %v", e)
 	}
-
-	if ret[len(ret)-1] != 9 {
-		t.Errorf("Expected VM to return 9, got", ret, "instead.")
+	if !bytes.Equal(ret, big9) {
+		t.Errorf("Wrong return value '%x', want '%x'", ret, big9)
 	}
 }