diff --git a/chain/actors/actor_init.go b/chain/actors/actor_init.go
index 4e5c1fe57..2424ecd7a 100644
--- a/chain/actors/actor_init.go
+++ b/chain/actors/actor_init.go
@@ -43,6 +43,14 @@ type ExecParams struct {
 	Params []byte
 }
 
+func (ep *ExecParams) UnmarshalCBOR(b []byte) (int, error) {
+	if err := cbor.DecodeInto(b, ep); err != nil {
+		return 0, err
+	}
+
+	return len(b), nil
+}
+
 func CreateExecParams(act cid.Cid, obj interface{}) ([]byte, error) {
 	encparams, err := cbor.DumpObject(obj)
 	if err != nil {
diff --git a/chain/actors/basicactor_test.go b/chain/actors/basicactor_test.go
new file mode 100644
index 000000000..1256222bc
--- /dev/null
+++ b/chain/actors/basicactor_test.go
@@ -0,0 +1 @@
+package actors
diff --git a/chain/actors/harness_test.go b/chain/actors/harness_test.go
new file mode 100644
index 000000000..cf9f11a7c
--- /dev/null
+++ b/chain/actors/harness_test.go
@@ -0,0 +1,150 @@
+package actors_test
+
+import (
+	"context"
+	"testing"
+
+	. "github.com/filecoin-project/go-lotus/chain/actors"
+
+	"github.com/filecoin-project/go-lotus/chain"
+	"github.com/filecoin-project/go-lotus/chain/address"
+	"github.com/filecoin-project/go-lotus/chain/types"
+
+	dstore "github.com/ipfs/go-datastore"
+	hamt "github.com/ipfs/go-hamt-ipld"
+	bstore "github.com/ipfs/go-ipfs-blockstore"
+	cbor "github.com/ipfs/go-ipld-cbor"
+)
+
+type Harness struct {
+	Steps []Step
+	From  address.Address
+
+	currStep int
+
+	t      *testing.T
+	actors []address.Address
+	vm     *chain.VM
+	bs     bstore.Blockstore
+	cs     *chain.ChainStore
+}
+
+type Step struct {
+	M   types.Message
+	Ret func(*testing.T, *types.MessageReceipt)
+	Err func(*testing.T, error)
+}
+
+func NewHarness(t *testing.T) *Harness {
+	h := &Harness{t: t}
+	h.bs = bstore.NewBlockstore(dstore.NewMapDatastore())
+
+	from := blsaddr(0)
+	maddr := blsaddr(1)
+
+	actors := map[address.Address]types.BigInt{
+		from:  types.NewInt(1000000),
+		maddr: types.NewInt(0),
+	}
+	st, err := chain.MakeInitialStateTree(h.bs, actors)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	stateroot, err := st.Flush()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	cs := chain.NewChainStore(h.bs, nil)
+
+	h.vm, err = chain.NewVM(stateroot, 1, maddr, cs)
+	if err != nil {
+		t.Fatal(err)
+	}
+	h.actors = []address.Address{from, maddr}
+	h.From = from
+	return h
+}
+
+func (h *Harness) Execute() *chain.StateTree {
+	for i, step := range h.Steps {
+		h.currStep = i
+		ret, err := h.vm.ApplyMessage(&step.M)
+		step.Ret(h.t, ret)
+		step.Err(h.t, err)
+	}
+	stateroot, err := h.vm.Flush(context.TODO())
+	if err != nil {
+		h.t.Fatal(err)
+	}
+	cst := hamt.CSTFromBstore(h.bs)
+	state, err := chain.LoadStateTree(cst, stateroot)
+	if err != nil {
+		h.t.Fatal(err)
+	}
+	return state
+}
+
+func (h *Harness) DumpObject(obj interface{}) []byte {
+	enc, err := cbor.DumpObject(obj)
+	if err != nil {
+		h.t.Fatal(err)
+	}
+	return enc
+}
+func (h *Harness) NoError(t *testing.T, err error) {
+	if err != nil {
+		t.Fatalf("Expected no errors from applying message in step %d. Got %s", h.currStep, err)
+	}
+}
+
+func TestVMInvokeHarness(t *testing.T) {
+	h := NewHarness(t)
+	var outaddr address.Address
+	h.Steps = []Step{
+		{
+			M: types.Message{
+				To:     InitActorAddress,
+				From:   h.From,
+				Method: 1,
+				Params: h.DumpObject(
+					&ExecParams{
+						Code:   StorageMinerCodeCid,
+						Params: []byte("cats"),
+					}),
+				GasPrice: types.NewInt(1),
+				GasLimit: types.NewInt(1),
+				Value:    types.NewInt(0),
+			},
+			Ret: func(t *testing.T, ret *types.MessageReceipt) {
+				if ret.ExitCode != 0 {
+					t.Fatal("invocation failed: ", ret.ExitCode)
+				}
+
+				var err error
+				outaddr, err = address.NewFromBytes(ret.Return)
+				if err != nil {
+					t.Fatal(err)
+				}
+
+				if outaddr.String() != "t0102" {
+					t.Fatal("hold up")
+				}
+			},
+			Err: h.NoError,
+		},
+	}
+
+	state := h.Execute()
+	_ = state
+	/*
+		act, err := state.GetActor(outaddr)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if act.Code != StorageMinerCodeCid {
+			t.Fatalf("Expected correct code, got %s, instead of %s", act.Code, StorageMinerCodeCid)
+		}
+	*/
+}