Fixing test command to use vendored modules
Added first unit test

Change-Id: I88f6ca906764dbb9a071607bc0e9410d1b84ef0c
diff --git a/internal/bbsim/devices/helpers.go b/internal/bbsim/devices/helpers.go
index d764943..920b1d4 100644
--- a/internal/bbsim/devices/helpers.go
+++ b/internal/bbsim/devices/helpers.go
@@ -1,9 +1,27 @@
+/*
+ * Copyright 2018-present Open Networking Foundation
+
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+
+ * http://www.apache.org/licenses/LICENSE-2.0
+
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 package devices
 
 import "github.com/looplab/fsm"
 
+var newFSM = fsm.NewFSM
+
 func getOperStateFSM(cb fsm.Callback) *fsm.FSM {
-	return fsm.NewFSM(
+	return newFSM(
 		"down",
 		fsm.Events{
 			{Name: "enable", Src: []string{"down"}, Dst: "up"},